Male Obesity-related Secondary Hypogonadism – Pathophysiology, Clinical Implications and Management

Along with the increased prevalence of obesity, the incidence of vitamin D deficiency is rising with 10–60 % of adults having values lower than 20 ng/ml.1,2 Serum or plasma 25-hydroxyvitamin D (25OHD) is the most widely accepted measure of vitamin D status (deficiency 30 ng/ml). Many studies have shown it is inversely associated with measures of obesity and that obese participants have lower suboptimal 25OHD levels compared with healthy weight participants.
Along with the increased prevalence of obesity, the incidence of vitamin D deficiency is rising with 10–60 % of adults having values lower than 20 ng/ml.1,2 Serum or plasma 25-hydroxyvitamin D (25OHD) is the most widely accepted measure of vitamin D status (deficiency 30 ng/ml). Many studies have shown it is inversely associated with measures of obesity and that obese participants have lower suboptimal 25OHD levels compared with healthy weight participants. Adipose tissue sequesters the fat-soluble vitamin and this leads to lower levels in obese populations. It is also thought that obese people may spend less time outdoors, or expose less skin to the sun, which may lead to reduced synthesis of vitamin D.

There has been increasing interest regarding the relationship between vitamin D, obesity, and weight loss, and this article will examine several aspects of this relationship, specifically looking at the effects of vitamin D supplementation and 25OHD levels on weight loss in adults. Possible mechanisms for the relationship between vitamin D and weight loss have been proposed.3,4 Inadequate vitamin D status has been suggested to promote greater adiposity through the regulation of parathyroid hormone (PTH) and modulation of adipogenesis. Increased PTH, a consequence of low vitamin D levels, promotes calcium influx into adipocytes and this intracellular calcium enhances lipogenesis and inhibits catecholamineinduced lipolysis, leading to accumulation of fat and weight gain.5,6 Achieving adequate vitamin D levels will lower PTH levels, which diminishes the calcium influx into adipocytes and increases lipolysis. 1,25-dihydroxyvitamin D, the active form of vitamin D, has also been shown to induce apoptosis in adipocytes.7,8 It has also been suggested that lower PTH levels via an increase in vitamin D levels could lead to weight loss through a sympathetic nervous system-mediated thermogenesis and lipolysis.3

Does Vitamin D Supplementation Lead to Weight Loss?
Several studies have investigated the effect of vitamin D supplementation on weight loss (see Table 1), although all were not specifically designed to analyze this. A secondary finding from a randomized controlled trial in men with impaired glucose tolerance designed to investigate glucose and lipid metabolism found a small but significantly greater weight reduction of 1.3 % using low-dose vitamin D compared with the placebo group with no weight loss after 3 months.9 Interestingly, 25OHD levels significantly increased in both groups, but there was a greater increase in placebo, although not reported as significant (14 % versus 39 %); consequently, it is difficult to conclude if the greater weight reduction was due to the low dose supplementation despite greater increase in placebo, which suggests a possible seasonal impact.

Following on from that study, the investigators conducted a longer uncontrolled study at a higher dose in 14 middle aged men with impaired glucose tolerance to investigate the effects on insulin sensitivity and glucose tolerance. Again, they found a small 1.1 % reduction in weight after supplementation for 18 months.10 25OHD levels were only measured after treatment and 6 months later so the study was unable to report if the low-dose supplementation increased 25OHD levels. Six months after supplementation 25OHD levels increased 37 %,10 suggesting a seasonal effect, which is likely since the study started and finished in the Fall.

Caan et al.11 measured changes in weight annually for an average of 7 years in 36,282 postmenopausal women in the Women’s Health Initiative clinical trial. Women who received daily vitamin D and calcium supplementation had minimal but consistent significant differences in weight compared with those taking placebo (–0.13 kg).11 These outcomes were observed primarily in women who reported inadequate calcium intakes (11 This modest difference could be explained by poor compliance with the supplementation, with the proportion consuming 80 % or more ranging 56–62 % and personal use of supplementation was allowed (up to 1,000 mg calcium and 600–1,000 IU vitamin D), which was equal or greater than the doses being investigated and may have masked any results.

In a similar study, Zhou et al.12 followed postmenopausal women randomized to vitamin D and calcium, calcium only, or placebo supplementation to look at the effect of supplementation on fractures. After 4 years, weight decreased in the vitamin D and calcium group, was unchanged in calcium group, and increased in placebo (values not reported).12 When looking at body composition, there was a gain in trunk fat mass and a loss of trunk lean mass, and this was greatest in the placebo group and similar in both supplemented groups.12 This suggested vitamin D had no added benefit; however, the changes in 25OHD levels were related to changes in body mass index (BMI) and trunk fat mass (r=–0.15; p12

There have also been vitamin D supplementation studies that have reported no changes in weight.13–17 All studies had significant increases in 25OHD levels following supplementation and found no changes in weight and other measures of body composition in a range of populations.13–16 Similarly, alehpour et al.17 found no differences in weight and waist circumference, but they did find a greater decrease in fat mass in those treated with vitamin D compared with placebo, and this modest reduction in fat mass was inversely correlated with the increase in 25OHD levels (r=–0.32; p=0.005).

When looking at studies that involved vitamin D supplementation without a weight loss component, there is a mixture of results. Some studies have shown minimal weight loss or prevention of weight gain, but have a range of limitations. Unfortunately, most of these studies also involved calcium supplementation or low-dose vitamin D supplementation, or study subjects could have been taking other vitamin D supplementation during the study, so it is difficult to draw conclusions from these studies as to whether vitamin D supplementation is effective for clinically significant weight loss.

Weight Loss Combined with Vitamin D and Calcium Supplementation
Studies have looked at the effect of combining weight loss strategies with vitamin D supplementation (see Table 2). Major et al.18 compared vitamin D and calcium supplementation with placebo during energy restriction in overweight or obese low calcium consumers. Both groups lost a similar amount of weight, fat mass, and waist circumference; however, when looking at a subgroup of only the very low calcium consumers they found that the vitamin D and calcium group lost significantly more weight and fat mass compared with placebo.19 Another study investigating overweight or obese very low calcium consumers undergoing energy restriction with or without a lower dose of vitamin D and calcium supplementation resulted in similar weight loss.20 However, supplementation resulted in greater reductions in fat mass (55.6 % higher), percent fat mass, visceral fat mass, and visceral fat area.20 While these studies have involved vitamin D supplementation, they also involved calcium supplementation and they have been more based around the calcium component, which is beyond the scope of this review. They also did not measure 25OHD levels so it is unable to determine if the dose was effective at improving vitamin D status.

Other studies have shown weight loss has not been influenced by vitamin D supplementation. Zittermann et al.21 found similar weight loss and reductions in fat mass and waist circumference between placebo and vitamin D oil, despite 25OHD levels increasing 185 %. Holecki et al.22 also found no difference in weight and fat loss between those supplemented with vitamin D and calcium and those with no supplementation in obese women undergoing lifestyle modification; however, this study did not find an increase in 25OHD levels, which suggests that the 0.25 μg dose was not effective.

Increases in Vitamin D Through Fortified Foods and Seasons
Studies have also looked at increasing vitamin D levels through other means, including fortified foods (see Table 3) and seasonal changes. Ortega and colleagues compared two hypocaloric diets: one increased cereals (enriched with vitamin D); the other increased vegetable intake for 2 weeks. Those on the cereal diet significantly increased their vitamin D intake and 25OHD levels compared with no changes in the vegetable diet.23 While both diets lost weight and fat, those on the cereal diet had greater reductions, suggesting that greater increases in 25OHD resulted in greater losses of body fat and weight.23,24 However, there was also a greater reduction in energy intake in cereal diet that was due to a ~1,000 kJ greater initial intake, which may also have contributed to the greater weight loss.23 While vitamin D intake was increased, it was still suboptimal and the differences were seen over a short time-frame of only 2 weeks. It is possible that greater improvements could be seen with a longer and higher dose supplementation.

Roseblum et al.25 compared the findings of two studies in overweight and obese adults: one with regular orange juice; one with reduced-energy orange juice. Both studies compared regular juice to juice fortified with vitamin D and calcium. When comparing the regular to fortified juice, the fortified group had a greater than 22 % increase in 25OHD levels. There was no difference in weight loss (~3 %); however, there was a greater reduction in visceral adipose tissue in the fortified juice groups.

Several studies have investigated the effect of milk fortified with vitamin D and calcium on weight, although primarily looking at other outcomes and not in combination with a weight loss component. The fortified milk products increased 25OHD levels by 6–11 % and the nonmilk groups decreased 12–19 %.26,27 One study found no differences in weight changes between the groups,26 and the other found weight significantly increased by 1.0 kg in the milk group compared with the nonmilk group and there was a trend for a greater increase in fat mass of 0.6 kg.27 The milk group in the second study also significantly increased their energy compared with no change in the other groups (+846 kJ/day), which could have impacted on the weight gain. Another study with fortified low-fat dairy products found no differences in weight change after 12 months of three dairy servings in combination with a dietary and lifestyle intervention compared with calcium supplementation and a control group.28 However, researchers did find combining lifestyle counseling with fortified dairy products had favourable changes in some different anthropometric and body composition indices (lower decrease in mid-arm muscle circumference, lower increase in sum of skin fold thickness, greater decrease in percentage of leg fat mass, and greater increase in percent of leg lean mass).28 25OHD levels were not measured, so they were not able to determine if the fortified products improved vitamin D status or if it was other parts of the intervention that were having the beneficial impact. In the majority of these studies the participants were vitamin D sufficient at baseline25–27 that, along with the low dose of vitamin D in the fortified products, could also have accounted for a modest increase in 25OHD levels. In some studies the products led to differences in energy intake that could have influenced subsequent weight loss and the products fortified with vitamin D and calcium. The dairy studies did not include a nonfortified dairy group, which again makes it difficult to distinguish between vitamin D and calcium, and also the impact of dairy, which may also affect adiposity.29

Different seasons are known to change 25OHD levels, with increases over summer months and decreases during winter. During a 20-week lifestyle intervention when vitamin D status improved due to seasonal change (winter to summer cohort) there were greater improvements in waist circumference compared to a cohort with reduced vitamin D status (summer to winter cohort –13.5 versus –8.4 cm, respectively).30 The increase in 25OHD was associated with a greater reduction in waist circumference (r=–0.48; p30 Dawson-Hughes et al.31 found the reduction in 25OHD levels due to seasonal change was attenuated by vitamin D supplementation (400 IU) in 249 healthy postmenopausal women, but found similar changes in weight, fat mass, and lean mass during these times when comparing vitamin D and placebo. While BMI was not reported, the average weight of the participants was approximately 68 kg and suggests they were not overweight so perhaps less likely to lose weight.

Do 25-Hydroxyvitamin D Levels Change with Weight Loss?
Many studies have reported lower 25OHD levels in overweight and obese populations, so it is possible they may increase with weight loss, in particular through the loss of adipose tissue, which would increase its bioavailability. Several weight loss/diet interventions have measured vitamin D before and after weight loss (see Table 4). Recently, Wamberg et al.32 observed a 27 % increase in 25OHD levels after 11 % weight loss and found the relative change in 25OHD levels correlated with relative weight loss. Another study found a similar increase in 25OHD levels (31 %) following 16 weeks of dietary support (14 % weight and 24 % fat mass loss) and there was a strong correlation between change in 25OHD levels and weight loss and a smaller but still significant correlation with fat mass changes.33 Both of these studies provided diet formula products to assist with weight loss that were enriched with vitamin D, but as they contained less than 8 μg/day, they were not likely to increase 25OHD levels to the extent seen in the studies. This suggests, along with the relationship between weight loss and changes in 25OHD, that the increases in 25OHD may be due to the weight loss.

A longitudinal study in obese women following 11.5 % weight loss found a 10 % increase in 25OHD levels.34 While this increase in 25OHD levels was significant, it was small and likely not clinically significant and 25OHD levels remained below those of normal weight women (40.1±18.6 ng/ml). Tzotzas et al.35 also observed a similar weight loss (10 % weight and percent fat mass loss and 9 % reduction in waist circumference) but saw a greater increase in 25OHD levels (34 %); however, the magnitude was the same (2.9 ng/ml).35 These participants were deficient at baseline and 25OHD levels were much lower and almost half of the previous study (15.4 ng/ml). There was a trend for a relationship between weight loss and change in 25OHD. However when assessed at 4 weeks when there was small but significant 4 % weight loss, there was no change in 25OHD. The diet contained an average 221 IU per day, which is below the recommended adequate intake, suggesting it did not lead to the increase in 25OHD. These results suggest that there might be a threshold of weight loss or time needed to see a significant increase in 25OHD levels.

By contrast, another study showed the opposite picture: Riedt and colleagues36 found no change in 25OHD levels following 7.2 % weight loss in premenopausal women. However in a subset of participants analyzed at week 6, there was a significant 27 % increase in 25OHD levels. It is likely that seasonal changes affected these findings, with the participants that were recruited in early fall having higher baseline values and smaller changes over 6 months compared with those recruited in late winter (baseline 32.9±8.2 versus 29.4±8.9 ng/ml; changes 1.1±17.9 % versus 19.8±18.2 %; respectively).36

There have also been studies that did not see any changes in 25OHD after weight loss. Hinton et al.37 found no changes in 25OHD levels post-12 weeks of weight loss and, interestingly, it decreased significantly following 24 weeks of weight maintenance. The researchers found a significant season by time interaction, indicating that the change in 25OHD levels was dependent on season during enrolment and suggested seasonal variation may have had a greater impact on 25OHD than changes in weight or fat mass.37 Mason et al.38 investigated overweight and obese postmenopausal women undergoing three different lifestyle modification programs and a control group and found no significant changes in 25OHD levels after 12 months compared with control participants, despite significant weight loss. Interestingly, the use of personal vitamin D supplementation decreased over the 12 months, with the proportion of participants taking supplements decreasing from ~50 % to 39 %; however, the daily intake among users increased (530 IU/day to 787 IU/day) and this could have influenced the study outcomes.38 However, what the study did find was a dose-dependent increase in 25OHD levels associated with the magnitude of weight loss, with greater weight loss having greater increase in 25OHD levels (38 Changes in 25OHD levels were also associated with reductions in BMI and fat mass.38

Rock et al.39 found a similar pattern with weight-change categories after a 2-year weight-loss intervention. Again, while they did not report an overall change in 25OHD levels for the entire study, they did find changes in 25OHD levels were mildly inversely correlated with changes in weight, and there was a significant linear trend between the change in 25OHD levels and weight change categories, such that those with greater weight loss had greater increases in 25OHD levels. During the study vitamin D supplement use increased from 20 % to 50 %; however, vitamin D use did not differ across the weight change categories, suggesting it was not supplement use that lead to greater increases in 25OHD in the weight-loss groups.

As mentioned above, some studies have also investigated the relationship between the changes in 25OHD levels and measures of body composition. The strength of these relationships ranges from 0.16 to 0.67, suggesting weak to strong relationships. Other studies, although not weight-loss studies, also found weak relationships between changes in fat mass and 25OHD levels.12,17

It appears that most studies either observed an increase in 25OHD levels, a pattern where there were greater increases in those that lost more weight or a relationship between the degree of weight loss and increases in 25OHD levels. It may be possible that a threshold of weight loss is needed to see an increase in 25OHD levels. Many of these studies were not primarily designed to measure the effect of weight loss on 25OHD levels so did not take season or prior use or changes in vitamin D supplementation into consideration in the study design, which may have greatly influenced some of the findings.

Do Baseline 25-Hydroxyvitamin D Levels Predict Subsequent Weight Loss?
It has been suggested that participants with better vitamin D status at the start of a weight-loss program may be more likely to experience successful weight loss. A study in 60 women found that those with baseline 25OHD levels 20 ng/ml or more lost more fat after 2 weeks of energy restriction compared with those with 25OHD levels less than 20 ng/ml (average 25OHD levels 31.9±15.5 versus 15.0±3.2 ng/ml; average fat loss –1.7±1.8 versus –0.5±0.8 kg, respectively).24 When split into groups 30 ng/ml or greater and 10 ng/ml or less, again, even greater fat loss was seen in those with higher 25OHD levels (–2.9±2.2 versus –0.4±0.7 kg) and also greater weight loss (–1.6±0.8 versus –0.8±0.7 kg).23 There was no difference in the reduction in energy intake between these groups, suggesting the baseline vitamin D status may be affecting the results, especially in those with sufficient levels. Although the sample size was small and the intervention was short, the resultant weight and fat loss was significantly greater in the group with higher 25OHD levels and suggests that those with better vitamin D status respond more positively to energy restriction and lose more fat and this could lead to even greater improvements seen over a longer time.

Shahar and colleagues40 followed 322 men and women undergoing weight loss via three different diets and found that baseline 25OHD levels were not associated with weight loss after 2 years. However they did find that higher 25OHD levels assessed at 6 months in a representative sample (n=126) were associated with greater weight loss after 2 years (tertiles of 25OHD: 14.5, 21.2, and 30.2 ng/ml; weight loss: –3.1±5.7, –3.8±4.4, and –5.6±6.6 kg).40 Interesting between-baseline and 6-months 25OHD levels decreased due to seasonal changes from summer to winter and when split into tertiles of change, those in the highest tertile which on average increased (median values, –9.2, –2.6 and 2.5 ng/ml) experienced greatest weight loss at 24 months (–2.5±4.9, –4.0±5.3, and –5.8±7.0 kg) and 6 months (statistics not reported, approximate values from graph, –3.5, –4, and –8 kg).40 25OHD values were not measured at the end of the study so unable to determine if they changed with weight loss over 24 months.

There were two other weight-loss studies that also showed no relationship between baseline 25OHD levels and subsequent weight loss.25,38 Baseline 25OHD levels were not associated with changes in BMI, subcutaneous adipose tissue, and visceral adipose tissue after 16 weeks25 and with greater weight loss, reductions in fat, or preservation of lean tissue after 12 months.38 However in one study the weight loss was minimal at 2.5 kg (~3 %) and the other stated the range of 25OHD levels were low overall and the range of concentrations may have been inadequate to detect an effect.38 Another study by Sneve et al.15 again found no differences in weight changes when dividing the cohort according to baseline 25OHD levels, but this was not a weight-loss study and there were no changes in weight overall during the study.

To date there has been inconsistent findings when looking at the effects of vitamin D supplementation on weight loss. Some studies have suggested that vitamin D status is associated with weight loss success, with supplementation resulting in weight loss, or higher baseline 25OHD or greater increases in 25OHD levels predicting better weight loss, although this has not been shown in all studies. Studies have also shown variations in response to vitamin D supplementation, with inter-individual differences in the effectiveness of supplementation41 and responses to vitamin D supplementation lower in obese participants compared with lean participants.42,43 These studies have had numerous limitations, including the combined use of vitamin D and calcium supplementation, which again make it difficult to distinguish between the two components, the use of low or inadequate doses of vitamin D, and the impact of changing seasons on 25OHD levels. Many studies were not specifically designed to analyze the effect of vitamin D supplementation on weight loss or if 25OHD levels change with weight loss so did not take season or prior use of or changes in vitamin D supplementation into consideration in the study design, which may have greatly impacted some of the findings. Some studies also showed improvements in other body composition measures besides weight, which suggests the need for a range of body composition assessment. These inconsistent findings and limitations make it difficult to draw conclusions on the benefit of vitamin D and 25OHD levels for weight loss. Future well-designed studies primarily aimed at investigating the effect of vitamin D supplementation and statuses on weight loss and changes in body composition are needed.

Belly fat linked to vitamin D deficiency

A new study reveals that individuals with higher levels of belly fat and larger waistlines are more likely to have lower vitamin D levels.

Share on PinterestWhere fat is stored on the body may impact vitamin D levels.

Currently, in medical circles, vitamin D is the talk of the town.

Produced in our skin on contact with sunlight, it plays a myriad of roles in the human body.

In the past few months, Medical News Today have covered a wealth of research into the group of fat-soluble secosteroids more commonly known as vitamin D.

For instance, recent studies have found that vitamin D might protect against heart failure, diabetes, and cancer, and that vitamin D deficiency causes hair loss.

Vitamin D deficiency has traditionally been linked to bone health, but it may also have a role to play in respiratory tract infections and autoimmune disease, among others.

With more than 40 percent of the population of the United States being vitamin D deficient, this is a serious issue. Some authors have referred to it as “an ignored epidemic,” estimating that over 1 billion people worldwide have inadequate levels.

Understanding vitamin D deficiency

As vitamin D’s importance becomes ever clearer, researchers are dedicating more and more time to understanding who might be most at risk of deficiency and working out ways to prevent it.

Because the vitamin appears to play a part in so many conditions, addressing the deficiency issue could have a considerable impact on the population at large.

One group of researchers investigating this topic hails from the VU University Medical Center and Leiden University Medical Center, both in the Netherlands. Led by Rachida Rafiq, they recently presented their findings at the European Society of Endocrinology annual meeting, held in Barcelona, Spain.

A between obesity and lower vitamin D levels has previously been spotted. Rafiq and team dug a little deeper; they set out to understand whether the type and location of fat played a role. To do this, they took data from the Netherlands Epidemiology of Obesity study, including thousands of men and women aged 45–65.

The team focused on total fat, abdominal subcutaneous adipose tissue (belly fat under the skin), visceral adipose tissue (around the organs), and hepatic fat (in the liver).

During their analysis, they adjusted the data for a range of potentially confounding variables, such as alcohol intake, smoking, ethnicity, education level, chronic disease, and physical activity levels.

Vitamin D and belly fat exposed

They discovered that in women, both total and abdominal fat were associated with lower vitamin D levels, but that abdominal fat had the greatest impact. In men, however, lower vitamin D levels were significantly linked with fat in the liver and abdomen.

Across both sexes, more belly fat predicted lower levels of vitamin D.

Rafiq explains, “he strong relationship between increasing amounts of abdominal fat and lower levels of vitamin D suggests that individuals with larger waistlines are at a greater risk of developing deficiency, and should consider having their vitamin D levels checked.”

Her next step is to understand why this relationship exists. Does a deficiency in vitamin D cause fat to be stored in the abdominal region, or does belly fat decrease levels of vitamin D? It will take more work to tease apart cause and effect.

As Rafiq explains, “Due to the observational nature of this study, we cannot draw a conclusion on the direction or cause of the association between obesity and vitamin D levels.”

“However, this strong association may point to a possible role for vitamin D in abdominal fat storage and function.”

Rachida Rafiq

The links between obesity and vitamin D deficiency are growing increasingly robust. The next challenge is working out a way to effectively tackle this issue.

Can Taking Vitamin D Help With Weight Loss?

Vitamin D is an essential nutrient, which means your body needs it but can’t make it without help. Traditionally the vitamin’s perceived importance was relegated to bone health. Inadequate vitamin D levels can lead to rickets in children and osteoporosis in adults.

But the past decade has witnessed a surge in vitamin D research, and much of it suggests that vitamin D is more multifunctional and crucial than previously believed. A 2014 review in the journal Frontiers in Physiology assembled evidence that low vitamin D status is associated with a range of inflammatory diseases—from arthritis and asthma to inflammatory bowel disease and lupus.

Research has also suggested that the vitamin may have a relationship to weight. “We know that individuals classified as overweight or obese tend to have lower blood levels of vitamin D, and this is true even after adjusting for sun exposure and intake of vitamin D supplements,” says Dr. Anne McTiernan, a research professor at the University of Washington School of Public Health.

McTiernan has studied the effect of vitamin D supplementation—2,000 IU/day of vitamin D3—on hormone activity and body weight changes in postmenopausal women who were also partaking in a weight-loss program. “Women whose blood levels of vitamin D rose to what is considered a normal level did lose more weight,” she says. Specifically, they dropped an average of 19 pounds, while women who did not achieve “normal” vitamin D status lost an average of 13 pounds.

“This suggests that women who want to lose weight could ask their doctor to check their vitamin D levels,” she says. “If the levels are too low, then the doctor will most likely advise the patient to take vitamin D.”

“Lower vitamin D seems to be a consequence of weight gain and obesity and not a cause of weight gain and obesity”

McTiernan says it’s possible that vitamin D somehow blocks the production of fat cells. Unfortunately, most of the existing research suggests the reverse relationship is more likely; a drop in fat leads to an uptick in circulating vitamin D levels.

“Vitamin D gets sponged up by adipose tissue and so is less likely to be in the blood if people are overweight or obese,” says Dr. Mark Moyad, director of preventive and alternative medicine at the University of Michigan. Moyad says that the elevated inflammation caused by obesity also drives down the blood’s vitamin D levels.

These associations have persuaded many people into thinking vitamin D can aid weight loss, he says. “But lower vitamin D seems to be a consequence of weight gain and obesity and not a cause of weight gain and obesity,” he explains.

Other experts echo his take. “There is no evidence for vitamin D on weight loss,” says Dr. Zhaoping Li, a professor of medicine and director of clinical nutrition at UCLA Medical Center.

Moyad says the same directionality seems to exist when it comes to vitamin D and other diseases. Behaviors that threaten your heart—like smoking or a sedentary lifestyle—can lower your blood’s levels of vitamin D. But taking D supplements won’t counteract the negative effects of these behaviors, he explains.

He points to a study published last year—one of the largest and most comprehensive vitamin D studies to date—that found giving people a vitamin D3 supplement did not lower their risk for heart disease, cancer, or risk of death. And more research has shown the links between vitamin D supplementation and inflammatory diseases like IBD are likewise “unclear.”

There also may be a link between low vitamin D and fatigue. In a 2014 study, researchers at the Cooper Medical School of Rowan University reported that people with low levels of vitamin D also had symptoms of fatigue and that normalizing their vitamin D levels significantly improved the severity of their fatigue symptoms. However, whether an increase in energy levels could translate to more exercise is unknown.

There’s no question that vitamin D is important to your health. And many Americans—maybe even a majority of them—have insufficient levels. But most of the evidence to date suggests low vitamin D is a consequence of being overweight or unwell—not the cause. And taking vitamin D supplements doesn’t seem to make these problems go away.

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We’ve known for some time that vitamin D deficiency is associated with developing obesity, and with health problems linked to obesity. The latest on this subject comes from a study presented at the 2015 European Congress on Obesity, which demonstrated that correcting levels of vitamin D could help you lose weight provided that tests find that you actually are vitamin D deficient. That’s not a very high bar to reach considering that vitamin D deficiency is widespread in the United States.

To explore whether vitamin D supplements could help people shed excess pounds, researchers at Italy’s University of Milan analyzed data from 400 obese or overweight patients from 2011 to 2013. The patients were all put on a low-calorie diet and were divided into three groups. Those in the first group took no vitamin D supplements. Group two received supplement totaling 25,000 international units (IUs) per month, and group three took 100,000 IUs per month.

After six months, the researchers found that only those patients taking 100,000 IUs per month had achieved optimal levels of the vitamin. However, they also found that participants who took either dose of D lost more weight than patients who followed the diet but took no supplemental vitamin D. Based on these findings, the researchers suggested that all people who are obese have their vitamin D levels tested, and advised them to start taking supplements if they are deficient.

I recommend a daily dose of at least 2,000 IUs of vitamin D. We can get vitamin D from foods such as fortified milk and cereals as well as eggs, salmon, tuna and mackerel, but the amounts found naturally in most foods are not significant. Sun exposure is the best way to maintain adequate levels; ultraviolet rays trigger vitamin D synthesis in the skin. In spite of the ability to make our own vitamin D, most people in the U.S. need to take supplemental vitamin D, especially seniors, as the ability to synthesize it in the skin declines with age.

Don’t be concerned that 2,000 IU daily will give you too much. With exposure to sunlight in the summer, the body can generate between 10,000 IU and 20,000 IU of vitamin D per hour with no ill effects. In addition, no adverse effects have been seen with supplemental vitamin D intakes up to 10,000 IU daily. What’s more, new research from the Mayo Clinic shows that out of more than 20,000 tests, only eight percent of people had levels higher than 50 nanograms per milliliter (ng/ml), which is considered high and only one percent had levels higher than 100 ng/ml. However, the researchers reported that even in those with levels of vitamin D over 50 ng/mL, no one had elevated serum calcium (hypercalcemia), which can occur when blood levels are very high. Too much calcium in the blood can cause weakness, lead to kidney stones, interfere with heart and brain function, and even prove life threatening. The Mayo Clinic researchers found only one case of true acute vitamin D toxicity over the 10-year span of the study. This occurred in an individual who had been taking 50,000 IUs of D daily plus calcium supplements for more than three months. For the record, the U.S. Institute of Medicine recommends an upper limit of vitamin D supplementation of 4,000 IU per day for those whose levels are low or deficient.

Andrew Weil, M.D.


Luisella Vigna et al. “Vitamin D supplementation promotes weight loss and waist circumference reduction in overweight/obese adults with hypovitaminosis d.” Presented at: European Congress on Obesity. May 6-9, 2015, Prague, Czechoslovakia

5 Ways Vitamin D Can Benefit Weight Loss

  1. Vitamin D Has Antioxidant and Anti-Inflammatory Benefits

As one of the 24 micronutrients necessary for survival, vitamin D affects genes within nearly every organ of your body. Vitamin D is responsible for the synthesis of numerous peptides that reduce stress and help the body fight off infection.

The nutrient also engages in molecular signaling to inhibit inflammatory substances from adhering to cell walls and causing stress and inflammation. In addition, the body’s organs also have receptors that turn vitamin D into the activated or hormonal form known as calcitriol.

This hormonal version of vitamin D helps repair cells, fights oxidation, and may even increase longevity. Notably, many of the top antioxidant and anti-inflammatory foods (such as olive oil, spinach, walnuts, and salmon) are also great natural sources of vitamin D.

  1. Vitamin D May Improve Lean Muscle Mass, Strength, and Bone Mineral Density

In addition to reducing belly fat, taking vitamin D for weight loss has important implications in musculoskeletal health. A 2017 study found that combining vitamin D with aerobic exercise and resistance training can result in more calorie loss than exercise alone.

Vitamin D may also help with energy output during strenuous workouts, and the nutrient can increase lean muscle mass over the course of a year. In men, vitamin D can greatly raise internal testosterone levels that prompt weight loss.

Along with exercise benefits, the body stores vitamin D and enables it to play an important role in muscle repair. Muscle tissue has special receptors for vitamin D that enable the nutrient to strengthen muscle fibers and help facilitate recovery from cellular damage.

For example, since the heart is a muscle, this organ also has special receptors for vitamin D. A study published in Circulation Journal found that people low in vitamin D are significantly more likely to develop cardiovascular disease. Therefore, taking vitamin D for weight loss also may help lower the rate of heart-disease risk markers like triglycerides.

Vitamin D may also inhibit the collection of scar tissue and fibroblasts following heart-related trauma. Overall, the vitamin can compound the benefits of cardiovascular workouts and benefit cardiovascular health.

The nutrient has other workout implications as well. Because there is an inverse relationship between internal vitamin D levels and mood swings, a lack of vitamin D can lead to muscle fatigue.

According to research, supplementing this essential nutrient may lead to greater stamina during exercise. The nutrient is also essential in the conversion of amino acid tryptophan into serotonin, a hormone greatly associated with an elevated mood and more energy.

Serotonin may also reduce intermittent feelings of uncontrollable hunger and increase the feelings of fullness after meals, protein shakes or snacking.

In addition, vitamin D may also help improve sleep and result in greater restfulness after a day of physical activity.

As an added bonus, vitamin D may reduce the release of cortisol, a stress hormone known to encourage the storage of belly fat. Since one of the main roles of vitamin D is to regulate and boost the absorption of calcium and phosphorous, the use of vitamin D can gradually increase bone density over time.

This bone density is not only important in the prevention of fractures – but it can also improve the bodily structure and overall fitness level.

  1. Vitamin D Can Help Counteract the Effects of Insulin Resistance

Studies have shown that people with type II diabetes or who are at risk for the condition may increase insulin secretion through vitamin D intake. The nutrient can also help with the hunger and overeating associated with insulin resistance and metabolic syndrome.

A study at the University of California at Davis found that high vitamin D levels result in the release of the hormone leptin. This hormone tells the body that it is full and may improve insulin sensitivity toward healthier foods.

  1. Vitamin D Has Helpful Implications for People Considering Gastric Bypass Surgery

Many people view gastric bypass surgery as a viable option for extreme weight loss. Also known as bariatric surgery, this procedure removes or restricts a large portion of the stomach and intestines. One of the problems with altering these organs is that it can significantly limit the amount of vitamin D absorbed from food.

In turn, this lack of vitamin D can lessen the long-term benefits of undergoing this surgery. Following the procedure, medical professionals may advise you to increase your vitamin D intake to help lower this risk of this deficiency.

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Large weight loss can mean significant vitamin D gain

Overweight or obese women with less-than-optimal levels of vitamin D who lose more than 15 percent of their body weight experience significant increases in circulating levels of this fat-soluble nutrient, according to a new study led by researchers in Hutchinson Center’s Public Health Sciences Division.
“Since vitamin D is generally lower in persons with obesity, it is possible that low vitamin D could account, in part, for the link between obesity and diseases such as cancer, heart disease and diabetes,” said Dr. Caitlin Mason, lead author of the paper, published online May 25 in the American Journal of Clinical Nutrition. “Determining whether weight loss helps change vitamin D status is important for understanding potential avenues for disease prevention,” said Mason, a postdoctoral research fellow.
How vitamin D supports health
According to the National Institutes of Health, vitamin D plays many important roles in the body. It promotes calcium absorption and is needed for bone growth and bone healing. Along with calcium, vitamin D helps protect older adults from osteoporosis. The nutrient also influences cell growth, neuromuscular and immune function, and reduces inflammation. Many gene-encoding proteins that regulate cell proliferation, differentiation and programmed cell death are modulated in part by the vitamin.
The yearlong study—one of the largest ever conducted to assess the effect of weight loss on vitamin D—involved 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups:

  • Exercise only
  • Diet only
  • Exercise plus diet
  • No intervention

Those who lost 5 percent to 10 percent of their body weight—equivalent to approximately 10 to 20 pounds for most of the women in the study— through diet and/or exercise saw a relatively small increase in blood levels of vitamin D (about 2.7 nanograms per milliliter, or ng/mL), whereas women who lost more than 15 percent of their weight experienced a nearly threefold increase in vitamin D (about 7.7 ng/mL), independent of dietary intake of the nutrient.
More weight loss, more circulating vitamin D gain
“We were surprised at the effect of weight loss greater than 15 percent on blood vitamin D levels,” said senior author Dr. Anne McTiernan, director of the Prevention Center and principal investigator of the study. “It appears that the relationship between weight loss and blood vitamin D is not linear but goes up dramatically with more weight loss. While weight loss of 5 percent to 10 percent is generally recommended to improve risk factors such as blood pressure, cholesterol and blood sugars, our findings suggest that more weight loss might be necessary to meaningfully raise blood vitamin D levels.”
About 70 percent of the participants had less-than-optimal levels of vitamin D when the study began; at baseline, the mean blood level of vitamin D among the study participants was 22.5 ng/mL. In addition, 12 percent of the women were at risk of vitamin D deficiency (blood levels of less than 12 ng/mL).
The optimal circulating range of vitamin D is thought to be between 20 and 50 ng/mL, according to a recent data review conducted by the Institute of Medicine, which found that blood levels under 20 ng/mL are inadequate for bone health and levels over 50 ng/mL are associated with potential adverse effects, such as an increased risk of developing kidney stones.
Daily dose of D
Vitamin D is naturally found in some foods, such as fatty fish, and is produced within the body when skin is exposed to sunlight. According to the Institute of Medicine, just 10 minutes of sun a day is enough to trigger adequate vitamin D production. The estimated average requirement via diet or supplementation is 400 international units per day for most adults.
“It is always best to discuss supplementation with your doctor, because circulating levels can vary a lot depending on factors such as age, weight, where you live, and how much time you spend outdoors,” Mason said. Vitamin D levels tend to decrease as people age and are generally lower among those with dark skin.
It is thought that obese and overweight people have lower levels of vitamin D because the nutrient is stored in fat deposits. During weight loss, it is suspected that the vitamin D that is trapped in the fat tissue is released into the blood and available for use throughout the body.
“Vitamin D is found in several different forms in the body and its pathways of action are very complex, so the degree to which vitamin D becomes available to the body as a result of weight loss is not well understood,” Mason cautioned.
Further studies on vitamin D deficiency and disease
A possible link between vitamin D deficiency and chronic diseases, including cancer and heart disease, is also not well established. “More targeted research ongoing at the Hutchinson Center and elsewhere aims to better understand whether vitamin D plays a specific role in the prevention of these chronic diseases,” McTiernan said. To that end, McTiernan is recruiting Seattle-area obese and overweight postmenopausal women for a separate new study to assess the impact of vitamin D on weight loss and breast cancer risk factors.
The National Institutes of Health, the National Cancer Institute and the Canadian Institutes of Health funded the research. Center authors included Liren Xiao, Carolyn Bain, and Drs. Ikuyo Imayama, Catherine Duggan, Ching-Yun Wang and Marian Neuhouser, all of PHS. The study also included investigators at the University of Washington, the University of Illinois at Chicago, the University of British Columbia, Case Western Reserve University, the University of Minnesota, the National Cancer Institute and Harvard Medical School.

Could Taking Vitamin D Help you Lose Weight?

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Key message: Taking vitamin D supplements can aid weight loss in obese and overweight people who are deficient in the vitamin.

Action point: Check your vitamin D levels with your health practitioner and then use this trusty app to track your vitamin D levels!

If you’re trying to lose weight, getting a healthy dose of vitamin D could help.

Vitamin D – also known as the ‘sunshine vitamin’ – is vital to strong bones and teeth and a healthy immune system. It is also especially important for menopausal women. As women get older, their bodies lose the capacity to activate vitamin D, which can increase the risk of osteoporosis.

Now researchers have linked low levels of vitamin D to obesity.

A Link Between low Vitamin D and Weight Gain?

Researchers at the University of Milan recruited 400 obese or overweight adults who were split into three groups – those who took no supplements, those who took 25,000 vitamin D units a month, and those who took 100,000.

All participants were put on the same balanced, low-calorie diet.

A significantly greater weight decrease and reduction in waist circumference was observed in both groups that took the supplements.

Those who took 25,000 units lost an average of 3.8kg, while the figure was 5.4kg for the 100,000 unit group and 1.2kg amongst those who took no supplements.

The study authors said:

“The present data indicate that in obese and overweight people with vitamin D deficiency, vitamin D supplementation aids weight loss and enhances the beneficial effects of a reduced-calorie diet.

“All people affected by obesity should have their levels of vitamin D tested to see if they are deficient, and if so, begin taking supplements.”

As most women experience weight gain during the menopause transition, it’s, it’s a great idea for women to pay attention to their intake of vitamin d at this time of life.

The Sunshine Vitamin

The best source of vitamin D is UV-B radiation from the sun.

According the Cancer Council of Australia, it’s important to balance the risk of skin cancer from too much sun exposure with maintaining adequate vitamin D levels 2.

For most people living in Australia, they recommend maintaining adequate levels of vitamin D in summer by spending only a few minutes of exposure to sunlight on your face, arms and hands or the equivalent area of skin on either side of the peak UV periods (the middle of the day when UV levels are most intense) on most days of the week.

In winter in the southern parts of Australia, where UV radiation levels are less intense, people may need about two to three hours of sunlight to the face, arms and hands, or equivalent area of skin, spread over a week to maintain adequate vitamin D levels.

In winter in northern parts of Australia, people will continue to maintain adequate vitamin D levels going about their day-to-day activities, so it is not necessary to deliberately seek UV radiation exposure.

European Congress on Obesity, news release, May 7, 2015


It was supposed to be a routine study.

At the University of Minnesota 2 years ago, Shalamar Sibley, M.D., was examining how calorie reduction might affect hormone pathways. On a hunch, she decided to test one more variable: vitamin D. “Researchers have been tracking the relationship between low vitamin D and obesity,” says Dr. Sibley. “So I wondered if people’s baseline vitamin D levels would predict their ability to lose weight when cutting calories.”

Her hunch paid off—big time. People with adequate vitamin D levels at the start of the study tended to lose more weight than those with low levels, even though everyone reduced their calorie intake equally. In fact, even a minuscule increase in a key D precursor caused the study participants to incinerate an additional half pound of flab.

Dr. Sibley’s study is just the latest indication that vitamin D could be our special ops agent in the war against body fat. “In the past decade, there’s been an explosion of research on vitamin D,” says Anthony Norman, Ph.D., a professor emeritus of biochemistry at the University of California at Riverside. For example, a study at Laval University in Quebec City found that people who consumed more dietary vitamin D had less belly fat than people who ate less.

What’s the big deal about D? It comes from milk and exposure to sunlight, right? Well, not really. Or at least, not enough of it does. More than a third of American men are deficient in the nutrient—even young, healthy men who live in sunny states. And many more American men—over 50 percent—have suboptimal levels.

“Vitamin D deficiency is one of the most commonly unrecognized medical conditions,” says Michael F. Holick, M.D., Ph.D., a professor of medicine at Boston University medical center and author of The Vitamin D Solution. “And that deficiency negatively affects every cell in your body—including your fat cells.”

Gimme a D! Gimme Another D!

One reason vitamin D has flown under the research radar for so long is because it’s more than just a vitamin—it’s also a hormone, one that plays a role in a remarkable range of body processes. “In the past 20 years, we’ve found D receptors on up to 40 different tissues, including the heart, pancreas, muscles, immune-system cells, and brain,” says Norman. He should know, having discovered the vitamin D receptor on intestinal cells back in 1969. So think of vitamin D as your body’s multitasking marvel: Heart disease? Adequate D might be equal to exercise in its ability to ward off this number one killer of men. Blood pressure? D helps keep it down. Diabetes? Yep, studies show that D can combat this, too. Now add to this list the potential to ward off memory loss, certain cancers (including prostate), and even the common cold, and it should come as no surprise that D may also help solve the riddle of your expanding middle. Here’s the rundown on the many benefits of boosting your vitamin D.

1 You’ll eat less but feel more satisfied.
When you have adequate vitamin D levels, your body releases more leptin, the hormone that conveys a “we’re full, stop eating” message to your brain. Conversely, less D means less leptin and more frequent visits to the line at the Chinese buffet. In fact, an Australian study showed that people who ate a breakfast high in D and calcium (a mineral that works hand in hand with D) blunted their appetites for the next 24 hours. Vitamin D deficiency is also linked to insulin resistance, which leads to hunger and overeating, says Liz Applegate, Ph.D., director of sports nutrition at the University of California at Davis.

2 You’ll store less fat.
When you have enough D in your bloodstream, fat cells slow their efforts to make and store fat, says Dr. Holick. But when your D is low, levels of parathyroid hormone (PTH) and a second hormone, calcitrol, rise, and that’s bad: High levels of these hormones turn your body into a fat miser, encouraging it to hoard fat instead of burning it, says Michael B. Zemel, Ph.D., director of the nutrition institute at the University of Tennessee. In fact, a Norwegian study found that elevated PTH levels increased a man’s risk of becoming overweight by 40 percent.

3 You’ll burn more fat—especially belly fat.
Vitamin D can help you lose lard all over, but it’s particularly helpful for the pounds above your belt. Studies at the University of Minnesota and Laval University found that D triggers weight loss primarily in the belly. One explanation: The nutrient may work with calcium to reduce production of cortisol, a stress hormone that causes you to store belly fat, says Zemel.

4 You’ll lose weight—and help your heart.
One of Zemel’s studies found that a diet high in dairy (which means plenty of calcium and vitamin D) helped people lose 70 percent more weight than a diet with the same number of calories but without high levels of those nutrients. What’s more, a German study showed that high levels of vitamin D actually increased the benefits of weight loss, improving cardiovascular risk markers like triglycerides.

Why Not Just Step Outside?

When sunlight hits your skin, your body’s built-in vitamin D factory kicks into operation, producing a form of the nutrient that lasts twice as long in your bloodstream as when you consume it through food or a supplement. The problem, of course, is a little thing called skin cancer: In order to manufacture enough D, you’d need to be in the sun during the peak hours of 10 a.m. to 3 p.m. without sunscreen, says Dr. Holick. But even if you could take cancer out of the equation, the amount of sunlight-derived D your body can produce depends on your location. People who live north of the equator probably make only 10 to 20 percent as much D in April as they do in June. And come December, a northerner’s skin can produce hardly any D, says Dr. Holick. Even living in a sunny city is no guarantee of adequate natural D. Air pollution filters UVB rays, so less of them are able to reach your skin. That’s one reason folks who live in Los Angeles and Atlanta tend to be deficient despite their sunny locations.

So Supplements Are the Answer?

Supplementing is a good idea. In fact, the Institute of Medicine recently unveiled a new D recommendation for food and/or supplements: 600 international units (IU) a day. But even that might not be enough. “The Institute of Medicine is extremely cautious,” says the University of California’s Norman. “Its guidelines are based on what it considers good for bone health, but that doesn’t address what’s needed to benefit the immune system, pancreas, muscles, heart, and brain.” Instead, Norman argues that men may need a 1,000 to 2,000 IU supplement plus a D-rich diet. Turns out, this view is shared by a group of experts in all things hormonal: The Endocrine Society recently released a revised recommendation of 1,500 to 2,000 IU a day for good health.

Still, even that elevated recommendation is just a starting point. If you’re overweight (that is, if your body mass index, or BMI, is over 25), you probably need more D. Body fat traps vitamin D in a Georges St-Pierre–style choke hold, preventing it from being used in your body. And the heavier you are, the more D is trapped and the less is available in your bloodstream. According to Dr. Holick, obese people (those with BMIs above 30) require two to five times the vitamin D that lean people need—a dosage that should be monitored by a doctor, of course. It’s less clear how much vitamin D you need if you are overweight but not obese, but somewhere between 2,000 and 4,000 IU is a safe bet, says Dr. Holick.

The other problem with trying to ingest all that D from a handful of pills is that you may not reap the fat-burning benefits you were hoping for. “Dietary sources of D usually contain complementary nutrients that also contribute to weight loss,” says Dr. Holick. Bottom line: A supplement is just that.

For More D, Cook This

Superdose yourself with over 1,400 IU by eating this dinner.

Grilled wild salmon, 900 IU
Lightly brush 6-ounce fillets with olive oil and sprinkle them with salt and pepper. Grill them skin side down for about 5 minutes; then flip them and grill until the flesh flakes when you prod the centers with a fork, 3 to 5 minutes more.

Dill-yogurt sauce, 30 IU
Serve the salmon with this quick yogurt sauce; a batch serves four. Mix 1 cup of vitamin D– fortified plain yogurt with half a cucumber (grated), 1 tablespoon of lemon juice, 2 teaspoons of chopped fresh dill, 1 minced garlic clove, and salt and pepper to taste.

Balsamic-glazed mushrooms and onions, 400 IU
You won’t find a lot of vitamin D in most produce—except Monterey Mushrooms, a brand of specialty mushrooms that have been exposed to UVB light. Use them in this easy side: On a baking sheet, toss 3 ounces of sliced mushrooms and ½ cup of sliced onions with olive oil and good-quality balsamic vinegar. Roast at 350°F until the mushrooms are lightly browned and glazed, about 40 minutes, stirring occasionally. Toss with chopped parsley.

And for Dessert…
Berry smoothie, 120 IU
In a blender, puree a handful of berries with a cup of D-fortified yogurt or kefir. Pour into a bowl; top with more berries and add cinnamon, which works along with D to help control blood sugar and insulin response.

Meet the Vitamin D Family

Fatty Fish
You can do better than bland white fish like flounder: Fatty varieties, such as salmon and mackerel, contain up to four times the vitamin D of lean fish. What’s more, these oily options also offer higher levels of omega-3 fatty acids—and omega-3s act in concert with vitamin D to promote weight loss and inhibit cancer-cell growth. “Of course you get the added benefit of appetite-suppressing protein, too,” says Chris Mohr, Ph.D., R.D., a consulting sports nutritionist for the Cincinnati Bengals.

Supercharge your D: Pick wild and not farm-raised salmon. A Boston University study found that farmed salmon has just 25 percent of the D of its wild cousins. Wild salmon derive their D from eating nutrient-rich plankton; farmed fish eat feed pellets, which are low in D.

Most milk products boast calcium as well as vitamin D, and you’ve already read about how calcium helps reduce levels of fat-storage hormones. Dairy is also rich in the amino acid leucine, which helps stimulate muscle growth and fat burning. The D and leucine may be why dairy sources of calcium are twice as effective as calcium supplements at promoting weight loss, says Zemel.

Supercharge your D: Choose D-fortified dairy products. All milk is fortified with 100 IU of vitamin D per serving, but yogurt and other dairy foods are hit or miss. Some yogurt brands are fortified with as much as 30 percent of the daily value per 6-ounce serving, while others aren’t fortified at all. This is also true of cereal, orange juice, and other fortified foods. Check labels to make the best choices.

Like fatty fish, eggs contain omega-3s and protein as well as vitamin D. Small wonder that eating an egg at breakfast while reducing calories can improve weight loss by 65 percent and reduce appetite throughout the day, according to two Saint Louis University studies.

Supercharge your D: Pick omega-enriched eggs, not conventional eggs. Eggland’s Best eggs, for example, are higher in omega-3s and also contain double the D.

Are You D-ficient?

If any of the following describes you, you might be deficient in vitamin D. To find out for sure, ask your doctor for a 25-hydroxyvitamin D test. You want to clock in above 40 nanograms per milliliter.

You’re in middle age or older.
The older you are, the harder it is for your skin to make D. In a Boston University study, 36 percent of men and women under age 30 were D deficient by the end of winter. That rate jumped to 42 percent for people over 50.

You’re a person of color.
The melanin pigment in your skin acts as a natural sunscreen, helping block UVB rays. The darker your skin (or the deeper your tan), the higher your natural SPF and the more sunlight your skin requires to make D.

Your body mass index is over 30.
Being obese increases your vitamin D needs by two to five times. Calculate your body mass index at Have a BMI over 30 but don’t think you’re fat? Ask for a skin fold test at your gym.

You’re a northerner.
Imagine a line running from Los Angeles to Atlanta and then to the Atlantic coast. If you live north of that line, there’s not enough sunlight for your skin to make adequate D between November and March, says Dr. Holick.

Alisa Bowman Alisa Bowman is a product developer and senior editor at Hearst.

Does vitamin-D supplement help you to lose weight?

Vitamin-D, or the sunshine vitamin, is known to be produced by our body with a mild exposure in the sun, or by consuming certain food or supplements. It is imperative to maintain adequate levels of the vitamin-D in your body, mainly because it helps your body to have a normal growth and better bones and teeth, as well as to facilitate a normal immune system function. But, the question is if vitamin-D foods or supplements help in losing weight?
As per the study, published in British Journal of Nutrition, people who are consuming a daily calcium and vitamin-D supplement were able to lose more weight much faster and in effective way than the ones who are not taking them. The experts concluded that an extra calcium and vitamin-D have an appetite-suppressing effect. Meaning, no more hunger hangs. Therefore, consider adding vitamin-D supplements to your diet, especially if you’re trying to lose weight. It is recommended to maintain a healthy food diet that is rich in vitamin-D. Here are some foods items that contain vitamin D:

  • Salmon: Salmon has high oil content, which is an excellent source of vitamin-D3.
  • Shrimp: Shrimp is the most popular type of shellfish, which is not only rich in vitamin-D, but are also very low in fat.
  • Mushroom: Mushroom is exposed to the sun while growing, meaning rich in vitamin-D value. However, pick white mushrooms, as they are an excellent source of vitamin-D than other mushrooms.
  • Egg Yolk: If you don’t fancy eating fish or seafood, then you can opt for egg yolk that are another good source of vitamin-D, as well as a delicious nutritious food.
  • Milk: Most of the packaged milk these days is fortified with vitamin-D. Daily intake of high amounts of fortified whole milk will help you to stay healthy and fit.

(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)

Vitamin D supplementation in obesity and during weight loss: A review of randomized controlled trials

Vitamin D deficiency is common in obese individuals and during weight loss. The recommended vitamin D doses in this specific population are higher than for healthy adults. We reviewed vitamin D supplementation trials in obesity, and during medical or surgical weight loss, and report the effects on 25-hydroxyvitamin D concentrations and other relevant outcomes.

We conducted a systematic search in PubMed, Medline, Embase and the Cochrane library for relevant randomized controlled trials (RCTs) of oral vitamin D supplementation for at least 3 months in obese individuals without weight loss (OB), and those on medical weight loss (MWL) (2010–2018), and following bariatric surgery (Bar S) (without time restriction). Two reviewers screened the identified citations in duplicate and independently and performed full text screening. One reviewer completed data extraction.

We identified 13 RCTs in OB, 6 in MWL and 7 in Bar S. Mean baseline 25(OH)D concentrations ranged between 7 and 27 ng/ml in OB, 15–29 ng/ml in MWL and 15–24 ng/ml in Bar S. In OB (Total N 2036 participants), vitamin D doses of 1600–4000 IU/d increased mean 25(OH)D concentrations to ≥30 ng/ml. Based on three trials during MWL (Total N 359 participants), vitamin D doses of 1200–4600 IU/d for 12 months increased 25(OH)D concentration to ≥30 ng/ml. In Bar S (Total N 615 participants), doses ≥2000 IU/d were needed to reach 30 ng/ml. The change in 25(OH)D concentration was inversely proportional to the administered dose, and to BMI and baseline level with doses of 600–3000 IU/day. With these doses, the change in 25(OH)D concentration per 100 IU/d was 0.5–1.2 ng/ml.

Three trials assessed bone mineral density as a primary outcome, but only one of them showed a protective effect of vitamin D against bone loss at all sites post-Bar S. There was no effect of vitamin D on weight loss. Data on extra-skeletal parameters, namely glycemic and vascular indices were mostly identified in OB, and findings were inconsistent.

In conclusion, Vitamin D doses ≥1600–2000 IU/d may be needed to reach a 25(OH)D concentration of 30 ng/ml in obese individuals and following bariatric surgery. The optimal concentration in this population is unknown, and whether the above doses protect against weight loss induced bone loss and fractures still needs to be confirmed. There is no clear evidence for a beneficial effect of vitamin D supplementation on cardio-metabolic parameters in obese individuals, and data on such parameters with weight loss are very scarce. Well-designed long term RCTs assessing the effect of vitamin D supplementation during weight loss on patient important outcomes are needed.

How Vitamin D Helps Weight Loss

Vitamin D helping weight loss has been demonstrated in a number of studies. Recent results show that overweight and obese people given Vitamin D supplements while on a reduced-calorie diet lost more weight than those on the same diet but without the added vitamin.

The success is noted especially in those who are deficient in the vitamin. This deficiency is widespread in North America. It is estimated that 40 percent of adults have low levels of the vitamin in their blood.

How Vitamin D Works

Vitamin D is known as the “sunshine vitamin” because sunlight falling on the skin creates the vitamin in the body. It is also widely available in foods such as eggs, yogurt, milk, orange juice, tuna, salmon and fortified cereals.

Who Benefits from Vitamin D and Weight Loss?

Those with a higher body fat percentage or BMI have been shown to have lower Vitamin D levels. One reason given is that they tend to eat fewer foods with while taking the vitamin. Another is they may not expose their skin to the sun as often, and also they may have lower levels of enzymes that convert the vitamin to its active state. An overweight or obese person needs more of it than a smaller-size person.

All overweight and obese persons should have their Vitamin D levels checked. The weight loss effect are seen in those who are deficient in the vitamin.

Studies on Vitamin D and Weight Loss

An Italian study involved 400 obese and overweight subjects with the deficiency. They were put on a reduced-calorie diet and were divided into three groups. One group received no supplements, one group took 25,000 IU of D, and the third group took 100,000 IU per month. At the end of six months, the two supplement groups lost more weight than the control group.

“The present data indicate that in obese and overweight people with Vitamin D deficiency, supplementation aids weight loss and enhances the beneficial effects of a reduced-calorie diet,” according to Luisella Vigna of the University of Milan, leader of the study.

“However, it is very important to note that the effect of Vitamin D appears to be limited to only those people who are deficient,” notes Dr. Christopher Ochner of Mt. Sinai Hospital in New York, an expert in weight loss, obesity and nutrition.

Vitamin D and Body Weight

Other studies provide more interesting data. One study shows that higher levels of the vitamin in the blood can aid not only in weight loss but in reducing body fat.

A year-long study involved 218 overweight and obese women who were all put on a reduced-calorie diet and an exercise program. One group received Vitamin D supplements, the other got a placebo. The group that received the vitamin lost an average of seven pounds more. Another study showed no weight loss but a decrease in body fat.

Vitamin D can raise levels of serotonin, a neurotransmitter associated with mood, sleep facilitation, and appetite control. Serotonin controls weight by reducing hunger and raising satiety.

It can also raise levels of testosterone which can aid in weight loss. A 2011 study showed that men given the vitamin had greater testosterone levels than a control group, according to a study.

Elevated testosterone levels can reduce body fat, maintain weight loss, and raise the metabolism, which will burn more calories and possibly block the creation of more fat cells. According to the study, “Testosterone supplementation in men decreases fat mass.” However, the mechanism is not known.

The Recommended Daily Allowance for Vitamin D is 600 IU per day. Some studies suggest this should be raised to 32 – 36 IU per pound a day.

Benefits of Vitamin D

It is very important to have adequate levels of Vitamin D in the blood. There are many benefits beyond weight loss. Maintaining the health of teeth and bones is well known. Other benefits include:

  • It supports the immune and nervous systems.
  • It helps diabetes management by regulating insulin levels. An inverse relationship between type 2 diabetes and Vitamin D levels has been shown in studies.
  • It helps lung function and heart health
  • Lack of Vitamin D can cause osteomalacia (soft bones) or osteoporosis, the common bone disease in post-menopausal women
  • In children, a reduced risk of influenza A has been noted.
  • Low Vitamin D levels are associated with an elevated risk of allergic diseases, including asthma, eczema, and atopic dermatitis in children.
  • It has been shown to lower the risk of gestational diabetes, preeclampsia, the necessity of a C-section and bacterial vaginosis during pregnancy
  • The possibility of benefits in cancer treatment has been studied. It may slow the progression of cancer by slowing down the growth of blood vessels in tumors.
  • Vitamin D deficiency has also been studied as possibly raising the risk of multiple sclerosis, Alzheimer’s disease, autism, swine flu, high blood pressure, rheumatoid arthritis, and more. But more studies to confirm these links must be done.

Side Effects of Vitamin D

Too much Vitamin D presents health problems. The upper limit for safe consumption is recommended to be 4000 IU per day. However, up to 10,000 IU will probably not cause side effects.

Symptoms of overdose are vomiting, diarrhea, constipation, headaches, nausea, metallic taste, dry mouth, and loss of appetite. Also, over-calcification of the blood vessels, bones, heart, lungs and kidneys can occur.

How to Use Vitamin D

Using large doses of any vitamin or supplement should be approved by a physician before the regimen begins.

  • Blood levels of Vitamin D should be determined by a physician
  • Sunshine up to 10 minutes per day is recommended
  • Foods suggested are eggs tuna, salmon, mackerel, liver, and Vitamin D-fortified foods
  • Vitamin D3 is preferred over D2
  • It should be taken with the largest meal of the day since it is a fat-soluble vitamin, meaning that it needs fat to be absorbed into the body.
  • Vitamin D is not always safe to take with other medications. Some examples are water pills, antacids, and Lipitor. This should be determined by a physician or pharmacist.

Studies indicate that supplementing a low-calorie diet and exercise plan with Vitamin D can be helpful. However, this has been shown to be beneficial only in obese and overweight people. In men, adding the vitamin can decrease fat tissue. However, there are side effects as noted, some serious and others minor.

There are many other health benefits of taking the supplement. What is known is that anyone contemplating adding the vitamin to a weight loss plan should visit his or her physician for determining blood levels, checking for compatibility with other drugs, and medical advice.

Ask the Diet Doctor: Vitamin D and Weight Loss


Q: Does vitamin D help you lose weight?

A: Currently the darling vitamin in the eyes of the media and many scientists, vitamin D has been linked to breast cancer outcomes, and low levels of the nutrient have been associated with a 200-percent increased risk of death in potential cardiac patients.

When it comes to weight loss, low levels of vitamin D are often observed in people who are overweight. It is thought that the hypothalamus (the very small part of your brain that regulates hormonal functions, amongst other things) senses low vitamin D levels and responds by increasing the body weight set point as well as the release of hunger-stimulating hormones. At the cellular level, vitamin D may also prevent the growth and maturation of fat cells.

The direct research looking at vitamin D and weight loss is still growing, but here is a sampling of what has been found so far:

  • A 12-week weight-loss study published in Nutrition Journal found that increasing vitamin D levels resulted in decreases in fat mass.
  • A 2012 study that looked at the impact of supplementing with both calcium and vitamin D found that this supplementation combination did not increase total weight loss but did lead to an increase in abdominal fat loss.
  • A 2010 study in the American Journal of Clinical Nutrition found that supplementing with vitamin D did not enhance weight loss, but it did improve other markers of health such as decreased triglyceride levels (a risk factor for heart disease) and TNF-alpha, a cellular marker of inflammation.

All of this may make you want to gorge on D, but more isn’t necessarily better; instead the key is keeping your vitamin D levels in the optimum range.

RELATED: What Vitamins Should You Take?

Simply going outside can help a little. When UVB rays hit your skin, your body photosynthesizes D-hence, it’s called the sunshine vitamin. Unfortunately geographic location plays a major role in the UVB rays that you have access to. If you live above the 37th parallel (which is anywhere approximately around San Francisco and Denver or above Tennessee and South Carolina), then the UVB rays won’t be right for you to make vitamin D. And even if you do live in the right place, other factors such as pollution and cloud cover can also impact how much vitamin D you will get while out in the sun.

From a dietary perspective, fatty fish are the major source, and fortified juices, milk, and cereals can also contribute to your daily intake.

When all these contributors are summed up, you will probably find that you are falling short of where you need to be. This is why I recommend that everyone supplement with 1,000 to 2,000 IU of vitamin D a day. This level of supplementation is less than the tolerable upper limit for vitamin D safety.

Lastly, you can also get a simple, non-fasted blood test to determine your D levels and then work with your doctor to coordinate the needed supplementation to optimize vitamin D for you and your health.

  • By Dr. Mike Roussell

Taking too much vitamin D can cloud its benefits and create health risks

Some people are overdoing it in search of better health.

Updated: December 15, 2019Published: November, 2017

Vitamin D is having its day in the sun. In recent years, research has associated low blood levels of the vitamin with higher risks of everything from heart disease, diabetes, and cancer to mood disorders and dementia. The findings have not gone unnoticed. Vitamin D supplements and screening tests have surged in popularity.

“Vitamin D testing is one of the top Medicare lab tests performed in the United States in recent years,” says Dr. JoAnn E. Manson, the Michael and Lee Bell Professor of Women’s Health at Harvard Medical School. “This is really surprising for a test that is recommended for only a small subset of the population.”

Unfortunately, this vitamin D trend isn’t all blue skies. Some people are overdoing it with supplements. Researchers looking at national survey data gathered between 1999 and 2014 found a 2.8% uptick in the number of people taking potentially unsafe amounts of vitamin D — that is, more than 4,000 international units (IU) per day, according to a research letter published in the June 20 issue of The Journal of the American Medical Association (JAMA). And during the same time period there was nearly an 18% increase in the number of people taking 1,000 IU or more of vitamin D daily, which is also beyond the dose of 600 to 800 IU recommended for most people.

Vitamin D and your health

Vitamin D, nicknamed the sunshine vitamin because your body produces it after sun exposure, has long been known to help build strong bones by increasing the body’s absorption of calcium and phosphorous. But beginning in 2000, research into vitamin D’s role in other health conditions began to expand rapidly.

While there is strong support for vitamin D’s role in bone health, the evidence that it prevents other health conditions is not yet conclusive, says Dr. Manson. “Research on vitamin D and calcium supplementation has been mixed and, especially when it comes to randomized clinical trials, has been generally disappointing to date,” she says.

Dr. Manson was a principal investigator of the recently published Vitamin D and Omega-3 Trial (VITAL), a large study (more than 25,000 participants nationwide). The study found that those taking a vitamin D supplement did not lower rates of heart attack, stroke, or cancer. However, among people who later developed cancer, those who took vitamin D supplements for at least two years had a 25% lower chance of dying from their cancer compared with those who received a placebo.

Factors that might affect your vitamin D levels

Your vitamin D levels reflect many factors. For example:

Where you live. If you live in the northern states (latitudes north of 37°), you are at higher risk for a vitamin D deficiency because your skin may not be able to produce any vitamin D from sun exposure during the winter months.

Your age. Your skin’s ability to produce vitamin D drops with age. If you’re over age 65, you generate only one-fourth as much vitamin D as you did in your 20s.

Your skin color. People with darker skin typically have lower levels of vitamin D than lighter-skinned individuals. African Americans have, on average, about half as much vitamin D in their blood compared with white Americans.

Your weight. If you have a body mass index above 30, you may have low blood levels of vitamin D. Vitamin D is stored in fat, so in people with obesity, less of the vitamin circulates in the blood, where it’s available for use by the body.

The foods you eat. Very few foods naturally contain vitamin D. The U.S. government started a vitamin D milk fortification program in the 1930s to combat rickets, a bone-weakening disease caused by vitamin D deficiency, which was a major public health problem at the time. Breakfast cereals and some types of orange juice may also be fortified, but this varies by brand. So, the amount of vitamin D you get from food depends on the food you eat and how much milk you drink.

Certain health conditions. People with conditions such as inflammatory bowel disease, liver disease, or cystic fibrosis, among others, may have trouble absorbing vitamin D, which can lead to deficiencies.

Looking for the link

Despite the fact that some studies have found an association between low blood levels of vitamin D and various diseases, it hasn’t been proven conclusively that a vitamin D deficiency actually causes disease, says Dr. Manson.

For example, a person with a serious illness may have a vitamin D deficiency. But that may have developed because she or he spends little time outdoors being physically active or because the person has a poor diet, both of which are risk factors for many diseases, as well as for deficiency, says Dr. Manson. Another issue is that diseases can cause inflammation, which can reduce vitamin D levels in the blood. Obesity, which has its own links to many conditions, can also reduce the amount of vitamin D in the blood because your body stores the vitamin in fat tissue, removing it from the bloodstream, where it would show up on tests. “Thus, a low vitamin D level may be a marker for other conditions, but not necessarily a direct cause of disease,” says Dr. Manson.

In addition to figuring out whether a lack of vitamin D causes disease, more studies are needed to determine if taking a supplement can reduce these risks, says Dr. Manson.

Vitamin D benefits and warnings

Although the research is still hazy, some people will benefit from taking vitamin D supplements, along with sufficient calcium intake, to promote their bone health. But they don’t require large amounts of vitamin D to get the benefit. “More is not necessarily better. In fact, more can be worse,” says Dr. Manson. For example, a 2010 study published in JAMA showed that intake of very high doses of vitamin D in older women was associated with more falls and fractures.

In addition, taking a supplement that contains too much vitamin D can be toxic in rare cases. It can lead to hypercalcemia, a condition in which too much calcium builds up in the blood, potentially forming deposits in the arteries or soft tissues. It may also predispose women to painful kidney stones.

If you’re taking vitamin D supplements, the take-home message is moderation. Taking too much can limit the benefits of the sunshine vitamin.

Selected food sources of vitamin D


International units

Salmon, pink, cooked, 3 ounces

Tuna fish, canned in oil, drained, 3 ounces

Sardines, canned in oil, drained, 3 ounces

Milk, nonfat, fortified, 8 ounces

Orange juice, fortified, 8 ounces

Egg, whole, cooked, scrambled, 1 large

Cheddar cheese, 1 ounce

Frozen yogurt, flavor other than chocolate, 8 ounces

Source: USDA National Nutrient Database for Standard Reference.

Be smart about D

To safely take vitamin D supplements, it’s best to stick to some simple guidelines:

Watch your numbers. If you’re taking a vitamin D supplement, you probably don’t need more than 600 to 800 IU per day, which is adequate for most people. Some people may need a higher dose, however, including those with a bone health disorder and those with a condition that interferes with the absorption of vitamin D or calcium, says Dr. Manson. Unless your doctor recommends it, avoid taking more than 4,000 IU per day, which is considered the safe upper limit.

Choose food over pills. If possible, it’s better to get your vitamin D from food sources rather than supplements (see “Selected food sources of vitamin D.”) Choose fortified dairy products (which have the nutrient added to the food), fatty fish, and sun-dried mushrooms, which are all high in vitamin D. The FDA has made it easier for you to see how much you’re getting, thanks to new nutrition labels that list the vitamin D content of foods.

Let your doctor know. “Many people are taking high-dose supplements on their own and their doctors may not even be aware of it,” says Dr. Manson. Discuss supplement use with your doctor to ensure that the amount you’re taking is appropriate for your needs. If you have a well-balanced diet, which regularly includes good sources of vitamin D, you may not need a supplement at all.

Image: © Hunterann/Getty Images

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Did you know vitamin D supplements can help get you motivated to workout? (Photo by Getty Images)

While we all know that supplementing vitamin D in the winter can decrease your chances of catching a cold or flu, many of us may not realize that the first rays of spring sunshine should not come as a cue to put your vitamin D away with your winter jacket. Although more sunlight means we’ll make more vitamin D, I still recommend taking at least 2,000 IU daily. And here’s why:

1. It improves muscle function
If you have chronic pain you may want to reassess your vitamin D levels.

New research shows, for the first time, a link between vitamin D and muscle function — including recovery from exercise and daily activities. It also explains why lower levels can lead to physical fatigue. Similar research done with adolescent girls found that vitamin D is positively related to muscle power, force, velocity and jump height.

And while you may not be too worried about your jump height, this research is relevant if you find it hard to even get to the gym — let alone hit your personal bests while you’re there.

2. It blunts your appetite
Beyond the clear impact on our mood, gloomy pre-spring weather can indeed make us fat. We produce vitamin D when our skin is exposed to the ultraviolet B (UVB) rays in bright sunlight. Beyond the established immune-enhancing benefits, rising vitamin D levels are also known to activate the production of leptin, which helps us slim down by signalling our brain and our stomach.

A study from Aberdeen University found that adequate levels of sunlight can significantly reduce obesity. After monitoring more than 3,100 post-menopausal women living in northeast Scotland over a two-year period they discovered that women who had the highest BMI also had the lowest amounts of vitamin D in their blood.

3. It can protect lung function
The sunshine vitamin will not only help you feel better, you’ll breathe easier too. According to a new study from researchers in Boston, vitamin D deficiency is associated with worse lung function and more rapid decline in lung function over time in smokers. This research suggests vitamin D may protect against some of the effects of smoking on lung function. The number one protector? Not smoking!

4. It can help you shed your winter weight
Vitamin D has been proven to lower insulin, improve serotonin levels, enhance the immune system, control appetite and even improve fat-loss efforts.

A study completed by a team at Massey University showed women who were given a daily dose of 4,000 IU of vitamin D3 showed improvements in their insulin resistance after six months of supplementation.

If that’s not enough, research from the University of Minnesota found that higher vitamin D levels in the body at the start of a low-calorie diet improved weight-loss success. Scientists determined that as vitamin D increased in the blood, subjects ended up losing almost a half-pound more on their calorie-restricted diet.

5. It can lower blood pressure
A 2012 study, presented at the European Society of Hypertension meeting in London, shows that vitamin D supplementation can help lower blood pressure in patients with hypertension. Similarly, additional research found that vitamin D deficiency in premenopausal women may increase the risk of developing high blood pressure even 15 years later – certainly a great reason to your levels optimized today for healthy aging.

Bottom line: It’s not all made equal
Despite all the health benefits, heading to the supplement store and picking out a vitamin D supplement blindly isn’t enough. You have to choose wisely.

New research funded by the Biotechnology and Biological Sciences Research Council (BBSRC) has shown that vitamin D3 supplements could provide more benefit than their close relative vitamin D2. The researchers analysed the results of 10 separate studies, involving more than 1,000 people, comparing the health benefits of vitamin D2 and D3, and found “a clear favouring” of vitamin D3 supplements in raising vitamin D serum levels in humans.

If you flip the label around, you can look for it to say D3 versus D2. If you prefer liquid, place the drops directly under your tongue for best absorption.

To find out more about how you can maximize your vitamin D levels visit the Vitamin D Council.

Natasha Turner, N.D. is a naturopathic doctor, Chatelaine magazine columnist, and author of the bestselling books The Hormone Diet and The Supercharged Hormone Diet. Her newest release, The Carb Sensitivity Program, is now available across Canada. She is also the founder of the Toronto-based Clear Medicine Wellness Boutique. For more wellness advice from Natasha Turner, .

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