Contents

An update on soy: It’s just so-so

Published: June, 2010

The onetime health food champion is an excellent source of protein, but it hasn’t lived up to its earlier billing.

These days, the notion of a separate category of health foods seems just a little out of date. Those stores with the bulk bins and organic produce are increasingly overshadowed by upscale chains like Whole Foods. And at many regular supermarkets, the crunchy, good-for-you foods aren’t as severely segregated into their own separate aisle or section. In fact, food and beverage companies are spending millions trying to persuade us that pretty much all of their products are healthful choices.

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Soy Protein and Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death in the United States.1 Diet has a major impact on several modifiable risk factors for heart disease: hypercholesterolemia, hypertriglyceridemia, elevated LDL cholesterol, low HDL cholesterol, hypertension, obesity, and diabetes. The recommended low-saturated-fat, low-cholesterol diet1 does help lower risk of CVD.23 However, other dietary factors may offer additional benefits.

There is increasing evidence that consumption of soy protein in place of animal protein lowers blood cholesterol levels and may provide other cardiovascular benefits. Epidemiologists have long noted that Asian populations who consume soy foods as a dietary staple have a lower incidence of CVD than those who consume a typical Western diet.4 Soy protein consumption in Japan is reported to be as much as 55 g/d,5 compared with <5 g/d in the United States.6 In 1998, deaths from CVD per 100 000 people between the ages of 35 and 74 years were as follows: 401 for US men, 201 for Japanese men, 197 for US women, and 99 for Japanese women.1 There are many differences in dietary patterns and lifestyle factors that could account for differences in disease patterns among countries.

The American Heart Association (AHA) Dietary Guidelines for Healthy American Adults2 stated that although there was some evidence that when soy protein was substituted for animal protein, total and LDL cholesterol could be reduced, the findings were inconclusive. The AHA Nutrition Committee concluded that the use of soy foods was consistent with the AHA Dietary Guidelines, but no recommendation was made to include soy protein in the diet. More research on the mechanisms explaining the effects of soy protein and related phytochemicals on blood lipids was recommended. This AHA Science Advisory provides an update on recent research reports.

The following description is from the Food and Drug Administration (FDA).7

Soy protein is an edible component of the soybean, Glycine max. Soy protein is produced from raw whole soybeans by a multistep process that removes the lipid and indigestible components to concentrate the protein and increase its availability. Depending on the particular steps used during processing, soy protein ingredients may take the form of isolated soy protein (ISP), soy protein concentrate, or soy flour. Each ingredient may be further processed into texturized soy protein or texturized vegetable protein (TVP) used in the manufacture of meat and poultry analogues by thermoplastic extrusion or steam texturization to impart structure and shape. In addition to protein, these soy protein ingredients contain other naturally occurring soy constituents, such as isoflavones, fiber, and saponins. The specific processing steps that are used determine the extent of retention of naturally occurring components in the final product.

Soy protein is also consumed as a component of traditional fermented and nonfermented soy foods, such as tofu, tempeh, and miso, as well as whole soybeans, soynuts, soymilk, soy yogurt, and soy cheese. These products contain variable amounts of soy protein and other naturally occurring soy constituents depending on the specific technologies used in these products. Soy protein ingredients and soy protein–containing foods may partially replace or be used in addition to animal or other vegetable protein sources in the human diet.

Clinical Studies

In 1995, a meta-analysis of 38 controlled clinical studies8 concluded that substituting soy protein for animal protein significantly lowered total cholesterol, LDL cholesterol, and triglycerides without affecting HDL cholesterol. These effects were greater in subjects with higher baseline cholesterol values. Daily soy protein consumption resulted in a 9.3% decrease in total serum cholesterol, a 12.9% decrease in LDL cholesterol, and a 10.5% decrease in triglycerides.8 The cholesterol-lowering effect of soy was in addition to the effect seen with a diet low in saturated fat and cholesterol (NCEP Step I diet).

Studies included in the meta-analysis8 used soy protein in the form of either TVP or ISP. No difference in efficacy was noted between these sources of soy protein, although the compositions of these soy products were quite different. TVP is usually made from a combination of soy flour and soy protein concentrate. Soy flour is ≈50% protein and contains ≈5% fiber. Soy concentrate is ≈65% to 70% protein and contains a small amount of fiber. ISP is ≈90% protein with no fiber.9 Soy protein contains all of the essential amino acids in sufficient quantities to support human life and is therefore a complete protein.9 Several components associated with soy protein have been implicated in the hypocholesterolemic benefits: trypsin inhibitors, phytic acid, saponins, isoflavones, and fiber. One major difference in soy concentrates and isolates is whether the manufacturer chooses to use water or ethanol washing to concentrate the protein. Ethanol washing removes most of the isoflavones and saponins. Unfortunately, at the time some of the earlier human studies were conducted, the exact processing conditions and composition information were not reported.

Studies in Adults With Normal Cholesterol Levels

It is important to note that consumption of soy protein does not appear to have a hypocholesterolemic effect in adults with low or normal cholesterol levels. Therefore, there is no need for concern that soy could cause dangerously low cholesterol levels. In a study of 12 adults with a mean total cholesterol level of 145 mg/dL at baseline, the incorporation of 66 to 80 g soy protein (meat replaced by soy analogues and milk replaced by soy beverage) resulted in no significant changes in serum lipids.10 Other investigators who studied the effect of soy protein as part of a hypocaloric diet found significantly lower total and LDL cholesterol compared with a conventional hypocaloric diet.1112 Sacks et al13 found no significant change in serum lipids in 13 strict vegetarians whose baseline cholesterol was 129 mg/dL. Wong et al14 found no significant change in 13 normocholesterolemic men 20 to 50 years of age (mean baseline total cholesterol, 169 mg/dL) who consumed 50 g soy protein in addition to a diet low in saturated fat and cholesterol. In the meta-analysis of the effect of soy protein on serum cholesterol levels by Anderson et al,8 no significant effect of soy protein was found for those with a cholesterol <200 mg/dL.

Studies in Adults With Elevated Cholesterol Levels

Although there have been some conflicting results in studies in adults with elevated serum cholesterol levels, most studies report total and LDL cholesterol reductions after the addition of soy protein to a diet that is low in saturated fat and cholesterol. In a recent study, postmenopausal women on a diet low in saturated fat and cholesterol (NCEP Step I diet) consumed 40 g/d of soy protein with either 56 or 90 mg of isoflavones daily or casein for 6 months. Both soy groups had significantly better blood lipid profiles (average change from baseline, 8.2% decrease in non-HDL cholesterol and a 4.4% increase in HDL cholesterol) than the casein group. However, no differences in lipids were seen between the 2 isoflavone levels.15 HDL significantly increased 7% from baseline with consumption of 32 g soy protein as soymilk in both women and men with hypercholesterolemia.16 Crouse et al17 reported reductions of 4% and 6% in total and LDL cholesterol, respectively, in hypercholesterolemic individuals consuming 25 g soy protein with isoflavones (see below) as part of a diet low in saturated fat and cholesterol.

A 9-week human study comparing the effects of soy protein (25 g/d) containing varying levels of isoflavones with those of casein found that consumption of the highest isoflavone level (62 mg/d) resulted in significantly lower total and LDL-cholesterol values than those of the casein group. Subjects with the highest LDL-cholesterol levels (top 50%) also experienced significant decreases in total and LDL cholesterol with 37 mg/d of isoflavones. However, those consuming soy protein with lower isoflavone levels (≤27 mg/d) did not have any significant cholesterol-lowering effect.17

Researchers have also addressed the question of the threshold of dietary soy protein needed to reduce cholesterol. A dose-response study in hypercholesterolemic men on an NCEP Step I diet used 20, 30, 40, or 50 g/d of soy protein compared with casein. After 6 weeks, all levels of soy consumption led to significantly greater reductions in non-HDL cholesterol (1.5% to 4.5%) than did the casein, with higher levels being more effective.18 An earlier study by Bakhit et al19 showed cholesterol lowering with as little as 25 g/d of ISP in hypercholesterolemic but not normocholesterolemic men. Thus, 20 to 50 g soy protein/d improved blood lipid levels (1.5% to 4.5%) in mildly hypercholesterolemic persons. The FDA recently published its final ruling on a food-labeling health claim for soy protein and cholesterol reduction stating that 25 g/d of soy protein, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.7

Mechanisms of Cholesterol Reduction by Soy

Several components associated with soy protein have been implicated in lowering cholesterol: trypsin inhibitors, phytic acid, saponins, isoflavins, and fiber.

Trypsin Inhibitors

Trypsin inhibitors are ubiquitous in foods. All soy products are heat-treated, which destroys most of the activity of trypsin inhibitors. Small amounts of the heat-stable Bowman-Birk inhibitor may exert a hypocholesterolemic effect by increasing the secretion of cholecystokinin. This would then stimulate bile acid synthesis from cholesterol and thus help to eliminate cholesterol through the gastrointestinal tract. However, animal studies have not demonstrated a hypocholesterolemic effect when trypsin inhibitor was added to the diet.20

Phytic Acid

Phytic acid, myoinositol hexaphosphate, is found in all nonfermented soy protein products and is very stable during heating. Phytic acid chelates zinc strongly in the intestinal tract, thus decreasing its absorption.21 A copper deficiency or a high ratio of zinc to copper results in a rise in blood cholesterol.22 The hypothesis advanced is that soy foods contain both copper and phytic acid and therefore may lower cholesterol levels by decreasing the ratio of zinc to copper.

Saponins

Saponins are heat-stable and are present in all of the soy protein products except those that are extracted with alcohol. These compounds may contribute to cholesterol lowering by increasing bile excretion.23

Fiber

Some researchers have reported that soy fiber lowers cholesterol levels in humans with hypercholesterolemia.24 Others have found that soy fiber has a hypocholesterolemic effect when added to other foods but that when added to soy protein it does not further enhance the hypocholesterolemic effect of the protein.1925 The soy protein products used in most published trials have contained little or no fiber. Thus, soy fiber does not appear to be a major factor in the lipid-lowering effects of soy foods.

Direct Protein Effects on Hormones

Early researchers noted in animal studies that the amino acids lysine and methionine tend to raise cholesterol levels, whereas arginine has the opposite effect.26 Soy protein, compared with animal protein sources, has a higher ratio of arginine to lysine and methionine. Interestingly, 2 animal studies found that a mixture of l-amino acids equivalent to the pattern of soy protein had an intermediate cholesterol-lowering effect that was not as pronounced as that of hydrolyzed whole soy protein.2728 Thus, some other component in the whole soy protein may have a beneficial effect beyond that of the protein alone. The higher arginine-to-lysine ratio of soy protein may decrease insulin and glucagon secretion, which would then inhibit lipogenesis.29 These soy protein effects on insulin and glucagon levels have been reported in hypercholesterolemic humans.30 In animal studies, thyroxine levels increased with consumption of soy protein.3132 High thyroxine levels were theorized to decrease cholesterol levels, but human studies have been inconsistent.3233

Protein Effects on LDL Receptors

Soybeans contain 2 types of storage proteins, the globulins 11S and 7S. Cell culture studies suggest that these globulins stimulate LDL receptor activity.34 On the basis of several clinical studies, Sirtori et al35 suggest that consumption of soy protein upregulates LDL receptors in humans. LDL receptor mRNA levels in mononuclear cells were much higher in subjects fed soy protein than in those fed casein.15

Soy Peptides and Bile Acids

Soy protein treated with proteases forms 2 distinct fractions: an insoluble high-molecular-weight fraction and a soluble lower-molecular-weight fraction. The insoluble fraction, when fed to rats, lowered blood cholesterol levels by increasing fecal excretion of sterols.36 The theory that soy protein lowers cholesterol by enhanced bile excretion has been explored extensively. Cholesterol lost from the body in the form of bile shifts the liver toward providing more cholesterol for increased bile acid synthesis and increases LDL receptor activity. Thus, the end result is increased LDL removal from the blood. However, human studies with soy have not shown an increase in fecal bile acid excretion.3738

Isoflavones

Isoflavones are present in all soy flours and in concentrates and isolates produced by a water extraction process. Isoflavones are phytoestrogens and are bioactive in humans. Soy is the major food source of isoflavones, which include genistein, daidzein, and glycetein. Isoflavones have been the subject of an intensive research effort evaluating their possible hypocholesterolemic effects,173940 antioxidant effects,41 and estrogen-like effects on blood vessels.4243

Isoflavones have weak estrogenic effects in both animals and humans. The beneficial effects of estrogen include lower LDL cholesterol and increased HDL cholesterol. Phytoestrogens presumably work in a similar, although less potent, manner. Soy protein containing isoflavones lowered cholesterol significantly more than soy protein without isoflavones in humans.173940 Crouse et al17 concluded that the cholesterol-lowering effect of soy protein is entirely due to isoflavones. However, Nestel et al42 found no changes in plasma lipid levels in women consuming extracted soy isoflavones (without soy protein), although there was improved systemic arterial compliance. Therefore, both soy protein and isoflavones may be needed for the maximal cholesterol-lowering effect of soy.

Soy protein (20% of diet) with isoflavones also inhibits formation of atherosclerotic lesions in primates.44 Soy protein without isoflavones had an intermediate effect in the primate study. Genistein is known to inhibit tyrosine kinase, an enzyme involved in the cascade of events leading to formation of thrombi and lesions.45 Isoflavones also act as antioxidants and can inhibit LDL oxidation.41 In another study, isoflavones enhanced vascular reactivity in female macaques.43 As noted above, an isoflavone extract from soy improved systemic arterial elasticity in women without effects on blood lipid levels.42 These studies indicate that isoflavones and/or other ethanol-soluble soy phytochemicals may have direct effects on the vascular system, independent of lipid metabolism.

Availability of Soy Foods

Soy foods have been consumed in Asian countries for hundreds of years but are fairly new to the Western dietary regimen. In the past 10 years, the variety of soy foods available in US stores has increased, yet food manufacturers still need to provide more acceptable soy-based foods for the consumer.46 The traditional Asian soybean curd, tofu, is becoming popular because it can be used in many dishes. It has a relatively bland flavor and can easily take the place of eggs or dairy products in many recipes. TVP is commonly used as a meat extender or replacement. Soy flour and ISP can be added to baked products to improve their nutritional quality without affecting their taste. New soy products are appearing that are replacements for common foods, such as soymilk and soy cheeses. Health-conscious Americans now have additional dietary choices that are low in saturated fat and contain virtually no cholesterol to assist in the control and/or reduction of total and LDL cholesterol.

Summary

Considering the totality of research, daily consumption of ≥25 g of soy protein with its associated phytochemicals intact can improve lipid profiles in hypercholesterolemic humans. This effect was observed in clinical trials to be additional to the benefits of an NCEP Step I diet and is greater in more-hypercholesterolemic subjects. The mechanisms by which soy modulates blood cholesterol and lipoprotein levels need further research. Soy protein without the isoflavones appears to be less effective. Consuming isoflavones without soy protein does not lower cholesterol but may provide other cardiovascular benefits. The effects of using soy extracts of isoflavones as dietary supplements are largely unknown and cannot be recommended.

Apparently there is a synergy among the components of intact soy protein, which provides the maximum hypocholesterolemic benefit. A variety of clinical trials have demonstrated that consuming 25 to 50 g/d of soy protein is both safe and effective in reducing LDL cholesterol by ≈4% to 8%. The beneficial effects of soy are proportionally greater in people with hypercholesterolemia. Lichtenstein47 has noted that the judicious substitution of soy for animal protein can result in lower saturated fat and cholesterol intakes, thereby indirectly resulting in a more favorable blood cholesterol level and potentially reducing coronary heart disease risk.

In conclusion, it is prudent to recommend including soy protein foods in a diet low in saturated fat and cholesterol to promote heart health.

This statement was approved by the American Heart Association Science Advisory and Coordinating Committee in August 2000. A single reprint is available by calling 800-242-8721 (US only) or writing the American Heart Association, Public Information, 7272 Greenville Ave, Dallas, TX 75231-4596. Ask for reprint No. 71-0196.

The author would like to thank Sandra Hannum, MS, RD, for her assistance in preparation of the manuscript.

Footnotes

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  • Soy beans, mature or dried: Not suitable.
  • Soy beans, immature, eaten as a vegetable (a.k.a. edamame): These have been laboratory tested at Monash University and are low in FODMAPs.
  • Soy milk: In the US, soy milk is usually made by grinding whole soybeans and water together. We then drink the soaking water and call it soy milk. It is therefore likely to be high in FODMAPs. In Australia, soy milk made a different way, from isolated soy protein instead of whole soy beans, was measured in the lab at Monash University. That type of soy milk is considered suitable for a low-FODMAP diet. (There are a couple of US brands that are made that way and might be OK for a low-FODMAP diet, but they haven’t been measured in the lab. Visit me on Pinterest to see them.)
  • Soy yogurt: probably high in FODMAPs because the main ingredient is soy milk (see above).
  • Soybean oil: No carbohydrates here, so no FODMAPs. Fine for the elimination phase.
  • Soybean lecithin: Not a source of FODMAPs. Suitable for the elimination phase.
  • Tofu block, floating in water, unseasoned: In the US, this might be called soft, firm, or extra firm tofu. This type of tofu has been measured and is low in FODMAPs. Tofu is made by coagulating soy milk, cutting it into blocks, pressing, and draining off the resulting liquid. The FODMAPs are in the liquid, which is not consumed. Suitable for the elimination phase of the diet.
  • Silken tofu: This type of tofu is made by coagulating soy milk right in the retail packaging. Instead of being pressed and drained, all parts of the soy milk are ultimately consumed. This makes it unsuitable for the elimination phase of the diet.
  • Soy sauce: Soy sauce has been measured in the lab and is low in FODMAPs. This probably goes for tamari sauce, too. Teriyaki sauce typically has garlic in it, so it should be avoided on the elimination phase unless it has been laboratory tested. Visit me on Pinterest.
  • Soy vegetarian crumbles, nuggets, burgers, etc.: These products vary, but it is likely that they all contain fiber from the whole soybeans they are made with; in addition, most will be seasoned with onions and garlic. These are not suitable for the elimination phase of the diet.
  • Soy protein powder: FODMAP status probably varies depending on how the protein powder was made. Soy protein isolate could potentially be low-FODMAP if it is very pure, but actual FODMAP status of a particular protein powder is unknown without laboratory testing, and should be avoided during the elimination phase of the diet.

Soy products that are not suitable for the elimination phase of the IBS-Free diet could be reintroduced when challenging GOS/oligosaccharides. Hope this sheds some light on soybeans!

A previous version of this article was originally published on May 18, 2014.

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Is Soy Good or Bad for Your Health?

While soy has several health benefits, its effects on other conditions are unclear.

Effect on Breast Cancer Is Unknown

Soy contains isoflavones, which act like estrogen in the body. Since many breast cancers need estrogen to grow, it would stand to reason that soy could increase breast cancer risk. However, this isn’t the case in most studies.

In a review of 35 studies on soy isoflavone intake and breast cancer incidence, higher soy intake reduced breast cancer risk in both pre- and postmenopausal Asian women.

For women in Western countries, one study showed soy intake had no effect on the risk of developing breast cancer (16).

This difference may be due to the different types of soy eaten in the Asian compared to the Western diet. Soy is typically consumed whole or fermented in Asian diets, whereas in Western countries, soy is mostly processed or in supplement form.

In an animal study, rats fed fermented soy milk were 20% less likely to develop breast cancer than rats not receiving this type of food. Rats fed soy isoflavones were 10–13% less likely to develop breast cancer (17).

Therefore, fermented soy may have a more protective effect against breast cancer compared to soy supplements.

Additionally, soy has been linked to a longer lifespan after breast cancer diagnosis.

In a review of five long-term studies, women who ate soy after diagnosis were 21% less likely to have a recurrence of cancer and 15% less likely to die than women who avoided soy (18).

Impact on Thyroid Function

Soy contains goitrogens, substances that may negatively impact the thyroid by blocking iodine absorption.

Test-tube and animal studies have shown that soy isoflavones block the production of thyroid hormones (19, 20).

Studies on the impact of soy on thyroid function in humans suggest it may not have a significant impact.

In a review of 14 studies, soy had little to no effect on thyroid function, and the authors concluded that people with hypothyroid disease do not need to avoid soy as long as their iodine intake is adequate (21).

Plus, two randomized trials in postmenopausal women found that up to 120 mg a day of soy isoflavones had no significant effect on thyroid hormone production (22, 23).

Effect on Male Sex Hormones

Because soy contains phytoestrogens, men may worry about including it in their diet.

However, studies do not indicate that soy negatively impacts the production of testosterone in men.

In a review of 15 studies in men, intake of soy foods, protein powders or isoflavone supplements up to 70 grams of soy protein and 240 mg of soy isoflavones per day did not affect free testosterone or total testosterone levels (24).

What’s more, soy may reduce the risk of prostate cancer in men.

In a review of 30 studies, high soy consumption was linked to a significantly lower risk of developing the disease (25).

Most Soy Contains GMOs

More than 90% of the soy produced in the US is genetically modified (26).

There’s much debate over the safety of genetically modified organisms (GMOs). More long-term scientific studies are necessary to determine their effects in humans and in what quantity they’re safe (27).

Additionally, most genetically modified soy products withstand the pesticide glyphosate which is controversial.

Certain GMO soy products have been found to contain glyphosate residues and have a poorer nutritional profile compared to organic soybeans (28).

Therefore, to avoid GMOs and exposure to glyphosate, stick with organic soy.

Summary Animal studies suggest that soy negatively impacts breast cancer, thyroid function and male hormones, but human studies suggest otherwise. The majority of soy is genetically modified, so eat organic soy if you want to avoid GMOs.

Just like spelt, soy products cause quite some confusion on the low FODMAP diet. The question “Is soy low FODMAP?” cannot be answered with just “yes” or “no” easily. The answer actually is “it depends”. Some soy products are low FODMAP, while others aren’t. In this blog, I am going to explain to you which soy products are safe to use on the low FODMAP diet.

Soy beans, of which soy products are made, contain high amounts of galactans and fructans and are therefore not low FODMAP. You would expect that all soy products made of soy beans are also high in FODMAPs then, but that is not the case. When soy beans are processed to make a certain soy product the FODMAP content in the soy product can become lower and therefore some soy products are low FODMAP and others aren’t.

Low FODMAP soy products

The products below are low FODMAP and can be used during the low FODMAP diet, in the serving sizes mentioned.

  • Soy sauce – Soy sauce is low FODMAP up to 42 gram per serving, 2 tablespoons. Tamari, gluten-free soy sauce, has not been tested, but because soy sauce is low FODMAP, tamari probably is too.
  • Ketjap – Ketjap is sweet soy sauce and is low FODMAP up to 20 gram per serving, 1 tablespoon.
  • Miso paste – Miso paste is often used in the Japanese cuisine, for example for making miso soup. Miso paste is low FODMAP up to 12 gram per serving, 2 tablespoons. Make sure no other high FODMAP ingredients have been added.
  • Tofu – Tofu is made of soy beans, but because of the processing of the soy beans to make them into tofu, the amount of FODMAPs in the tofu is lowered and that’s why tofu is low FODMAP. Make sure that you use “firm” tofu and no “soft” or “silken” tofu because the latter is high in FODMAPs.
  • Tempeh – Tempeh is made of fermented soy beans. The fermentation process lowers the amount of FODMAPs in the soy beans and therefore tempeh is low FODMAP. Large servings of tempeh of 220 gram or more are high in FODMAPs. A serving of 100 or 150 gram can be eaten safely.
  • Edamame beans – Edamame beans are young immature soy beans and these are low FODMAP up to 90 gram per serving. At 210 gram they contain a high amount of fructans and are no longer low in FODMAPs.
  • Soybean oil – Foods that only contain fats don’t contain any FODMAPs because FODMAPs are carbohydrates. Therefore soybean oil is low FODMAP.
  • Soy lecithin – Soy lecithin is often added to processed foods. You can find it in the ingredient list of many chocolate bars for example. Soy lecithin is a combination of fat and oil and is therefore low FODMAP.
  • Soy milk made from soy protein – Soy milk made from soy protein is low FODMAP in a serving of 250 ml. Unfortunately, the most common soy milks are made from whole or hulled soy beans and therefore soy milk made from soy protein is hard to find. At least here in the Netherlands, I never managed to find it.
  • Cheese made from soy – These are often vegan cheese variations. The Monash app says that soy cheese is low FODMAP up to 40 gram per serving. Make sure to check that no other ingredients have been added to the cheese that are high in FODMAPs.

These soy products are not low FODMAP

  • Silken tofu – As mentioned above, “firm” tofu is low FODMAP, but silken tofu is not.
  • Soy beans – Edamame beans are immature unripe soybeans and these are low FODMAP. Mature soybeans (you often find these canned or dried) are not low FODMAP and contain high amounts of galactans and fructans.
  • Soy milk made from soy beans – Soy milk made from soy beans is higher in FODMAPs than soy milk made from soy protein. The Monash app says that soy milk made from hulled soy beans is low FODMAP up to 60 ml per serving and soy milk made from whole soy beans is low FODMAP up to 30 ml per serving. For soy milk, I advise to avoid it during the elimination phase and reintroduction phase. If you have finished the reintroduction phase and know how you react to galactans and fructans, you can test soy milk and see how you react to it.

These were the soy products that are listed in the Monash University low FODMAP app. Below I will go a bit deeper into a few soy products that are a bit more difficult to give a high or low FODMAP label: soy flour, soy yoghurt and soy protein powder.

Is soy flour low FODMAP?

Soy flour is often used in gluten-free products. Soy flour has not been tested by by Monash University yet, but it has been tested by FODMAP Friendly (another organisation that tests products on their FODMAP content). They have tested an amount 0f 50 gram of soy flour and this turned out to be high in FODMAPs.

We do also have a reason to believe that soy flour is low in FODMAPs in smaller amounts. There are several products that have been low FODMAP certified, such as the gluten-free digestive cookies from Schär, that contain soy flour. Therefore, soy flour is probably low FODMAP in very small amounts.

When soy flour is in a gluten-free product and it is not too far in the front of the ingredient list (the more in the front an ingredient is, the more the product contains of it) and the product doesn’t contain any other ingredients that are high in FODMAPs, it is probably safe to eat. If a product contains a lot of soy flour, you can better avoid it.

Is soy yoghurt low FODMAP?

Soy yoghurt has not been tested by Monash University. Just as with milk, the amount of FODMAPs in soy yoghurt can differ per brand and per product. Some soy yoghurt is made of whole soy beans and other kinds are made of hulled soy beans. Without testing it is hard to say how high the amount of FODMAPs in a certain kind of soy yoghurt is.

Because soy milk made of hulled soy beans is lower in FODMAPs than soy milk made of whole soy beans, the same probably counts for soy yoghurt.

The advice for soy yoghurt is the same as for soy milk: try to avoid it during the elimination and reintroduction phase and test it afterwards. There are people who react very well to soy yoghurt and there are people who don’t. It is really necessary to test it for yourself to find out.

I often hear from fodmappers that their dietician advised them to start using soy “dairy” products, such as soy milk, soy yoghurt and soy desserts. As you have read above, these products are not or very limited low FODMAP. Therefore my advice would be to be very careful with them and only use the soy products that are low FODMAP.

What about soy protein powder?

As soy milk made from soy protein is low FODMAP, I sometimes hear the question whether soy protein powder is low FODMAP too. Soy protein powder or soy protein isolate has not been tested by Monash University yet, but it might be possible that it is low FODMAP. Again, this depends on the processing of the soy.

In order to find out if you can tolerate soy protein powder, you will have to test it. Again, the advise is to do this after the elimination and reintroduction phase. Make sure to read the ingredient list of the soy protein powder well because often sneaky FODMAPs, such as fructose, have been added. If that is the case, the soy protein powder is not low FODMAP for sure.

I hope that I have been able to answer the question “Is soy low FODMAP?” in this blog. If you have any more questions about soy, feel free to ask them below and I will try to help you.

Sources used for this article:

  • Monash University FODMAP diet app
  • FODMAP friendly – Is soy flour low FODMAP

Together we go for a calm belly!

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Everything You Need to Know About Soy Food

Tons of non-meat eaters turn to soy to get their protein fill, so much so that you’d be hard-pressed to find a vegetarian alternative food product that doesn’t contain soy. You’ll find it in tofu, miso soup, edamame, milk alternatives, and basically every veggie burger in the frozen food aisle. Needless to say, consumption has skyrocketed in recent years. In 2013, the soy foods industry in the U.S. totaled $4.5 billion, which is a big jump from the $1 billion it brought in in 1996, according to research by Katahdin Ventures, a marketing and content development firm focused on agriculture and sustainability.

The Benefits of Soy

Soybeans deliver a high protein count for significantly fewer calories than most meat. Not only that, but soy also contains all of the essential amino acids, which gives it a huge leg up on other plant proteins. Plus, soy is rich in fiber, free of cholesterol, and doesn’t have the saturated fat content that you’d find in animal products.

Straight-up nutrition facts aside, soy provides a number of health advantages. Research shows that eating soy products can reduce the risk of a stroke and lung cancer among nonsmoking women and can increase the chances of survival for women who already have lung cancer.

Debunking the Myths Surrounding Soy

Though there are tons of alleged benefits of soy, solid research simply isn’t all there yet. Soy research is so complicated because the amount of isoflavones, which are estrogen-like compounds that are found naturally in soy, can vary widely from product to product.

At some point, you’ve probably heard that women with breast cancer should stay away from soy. The initial studies, which were done on rats, indicated there could be a link between soy and breast cancer, says registered dietitian Dawn Orsaeo. But research on humans suggests otherwise. A meta-analysis of 35 studies published in the journal PLOS ONE found no correlation between soy and breast cancer for most women. A separate study from U.K. researchers determined that eating soy foods-even in high amounts as is common in many Asian cultures-can reduce the risk of breast cancer recurrence.

There is one risk, however, that’s gone pretty much undisputed: People with thyroid issues should limit their soy intake. Soy is a goitrogen, which means it promotes the growth of the thyroid gland. A study from U.K. researchers found people with hypothyroidism who followed a diet filled with 16 milligrams of soy phytoestrogens a day (which is about what you’d find in an average vegetarian diet) increased their risk of developing overt hypothyroidism three-fold compared with people who followed a diet with only 2 milligrams of phytoestrogens a day.

And you’d think eating soy rather than fatty meat would be good for your heart, but a study published in the American Journal of Clinical Nutrition found no such perk. The researchers compared a diet rich in soy beans, soy flour, and soy milk with a diet heavy in meat, chicken, and dairy products. Both diets contained about the same amount of cholesterol, fiber, and fatty acids throughout the study. In the end, the results were pretty boring. No major differences in cardiovascular disease risk factors were found.

The Whole Truth About Soy Foods

A study from Alternative Therapies in Health and Medicine acknowledged that soy is controversial, so the researchers decided to look at studies from a big-picture point of view. They found that yes, soy does have some benefits, but there are some question marks, like all those times when a study says one thing and then two years later another study completely goes against it.

Until more sweeping conclusions are made, don’t feel pressure to pop veggie burgers in the microwave on the reg. Even though they don’t have as much fat as meat, they likely are loaded up with sodium and artificial ingredients. “Instead, go for whole soy foods, like soy milk, edamame, soybeans, or soy nuts,” suggests Orsaeo. And keep an eye on your overall intake. “The recommendation from the American Institute for Cancer Research is to have no more than three servings in a day, which most Americans aren’t going to do anyway.”

  • By By Moira Lawler

Living With Food Allergies

Soy Allergy

Soy allergy is a common allergy among children. Approximately 0.4% of American children have a soy allergy. Most children outgrow their soy allergy by the age of 10.¹
Children with a soy allergy must avoid soy in all forms. This includes all soy products and where soy is listed as an ingredient.

How to Read a Label for Soy

Always read the entire ingredient label to look for the names of soy. Soy ingredients may be within the list of the ingredients. Or it could be listed in a “Contains: Soy” statement beneath the list of ingredients. This is required by the federal Food Allergen Labeling and Consumer Protection Act (FALCPA). Learn more about the U.S. food allergen labeling law.

FALCPA requires that all packaged foods regulated by the FDA must list “soy” clearly on the ingredient label if it contains soy*. Advisory statements such as “may contain soy” or “made in a facility with soy” are voluntary. Advisory statements are not required by any federal labeling law. Discuss with your doctor if you may eat products with these labels or if you should avoid them.

Did you know that edamame, miso and yuba all contain soy? The FDA food allergen label law requires foods to state if they contain a top 8 allergen such as soy. But, there are many foods and products that are not covered by the law, so it is still important to know how to read a label for soy ingredients. Products exempt from plain English labeling rules: (1) Foods that are not regulated by the FDA. (2) Cosmetics and personal care items. (3) Prescription and over-the-counter medications. (4) Toys, crafts and pet food. Download and print our Soy Allergy Avoidance List and Travel Cards to carry with you and share.

CONTAIN SOY

The following ingredients found on a label indicate the presence of soy protein. All labels should be read carefully before consuming a product, even if it has been used safely in the past.

Bean curd
Edamame (soybeans in pods)
Hydrolyzed soy protein
Kinako (roasted soybean flour)
Koya dofu (freeze dried tofu)
Miso
Natto
Okara (soy pulp)
Shoyu
Soy albumin
Soy concentrate
Soy fiber
Soy formula
Soy grits
Soy milk
Soy miso
Soy nuts
Soy nut butter
Soy protein, soy protein concentrate, soy protein isolate
Soy sauce
Soy sprouts
Soya
Soya flour
Soybeans
Soybean granules
Soybean curd
Soybean flour
Soy lecithin**
Soybean paste
Supro
Tamari
Tempeh
Teriyaki sauce
Textured soy flour (TSF)
Textured soy protein (TSP)
Textured vegetable protein (TVP)
Tofu
Yaki-dofu (grilled tofu)
Yuba (bean curd)

SOY IS SOMETIMES FOUND IN

Artificial flavoring
Asian foods (e.g. Japanese, Chinese, Thai, etc.)
Baked goods
Hydrolyzed plant protein
Hydrolyzed vegetable protein (HVP)
Lecithin**
Natural flavoring
Vegetable broth
Vegetable gum
Vegetable starch
However, if the product is an FDA regulated food, the word “Soy” must appear on the label.

SHOULD BE SAFE
These soy derivatives should be safe for most soy-allergic individuals:
*Soy oil (but avoid cold pressed, expeller pressed or extruded soybean oil)
*Vegetable oil derived from soy

TAKE NOTE
**Lecithin: Products that are covered by the FDA labeling laws and contain soy lecithin as an ingredient must be labeled to state that they contain soy.

*Soy Oil and Soy Lecithin

Highly refined soy or soybean oil will not be labeled as a major allergen on an ingredient statement. There are clinical studies showing that highly refined oils can be safely eaten by food allergic individuals. This is because highly refined oils contain extremely small levels of allergenic protein.

However, people with soy allergy need to avoid any expeller pressed, extruded or cold pressed soy oil. These types of oil do contain soy protein and must be listed on the label as an allergen.

Soy lecithin contains a small amount of soy protein. For this reason, products containing soy lecithin will label those foods for the presence of soy. The amount of soy protein in soy lecithin is low enough that it usually does not result in an allergic reaction in most people allergic to soy.³

Check with your doctor about whether you need to avoid soy lecithin and soy oil.

Cross Reactivity: Do You Need to Avoid Foods Related to Soy?

Cross-reactivity occurs when the proteins in one food are similar to the proteins in another. When that happens, the body’s immune system sees them as the same.

Soy is a legume. The legume family includes different beans, including peanuts and lentils. A common question that comes up for people with an allergy to one legume is whether they can eat other legumes. It turns out that 95% of individuals who are allergic to one legume can tolerate and eat other legumes. Many years ago, it was common to recommend avoidance of legumes, if allergic to another legume. This practice has been proven unnecessary.

Nutrition for a Soy-Free Diet

Soybeans provide one of the highest quality proteins in a child’s diet. They also contain thiamin, riboflavin, iron, phosphorus, magnesium, calcium, zinc and vitamin B6. Unless your child consumes large portions of soy, the small amounts of soy in processed foods do not supply a significant amount of these nutrients. A soy-restricted diet will not pose any nutritional risk if your child is eating a variety of fruits, vegetables, enriched and fortified grains, and tolerated sources of protein.

NUTRIENTS LOST
WHEN AVOIDING SOY
SUGGESTED ALTERNATE SOURCES
(if not allergic)
Protein, Thiamin, Riboflavin, Iron, Calcium, Zinc, Vitamin B6 Increase other protein foods such as meat, fish, poultry, legumes, eggs,
dairy (if safe for your child);
fruit, vegetables, leafy greens and enriched grains

Soy Substitutions in Recipes

Soy is a common ingredient in foods in the US. Rice-based and coconut-based alternatives are available if you need to avoid cow’s milk and soy. Whole soy beans (edamame) can be replaced with other beans (fava, garbanzo).

Learn more about using SOY SUBSTITUTES.

Soy-Free Recipes

Over 1,100 soy-free recipes are available in KFA’s Safe Eats™ Recipes. Search for Soy-Free Recipes

Hummus

Bacon and Brown Sugar Dogs

Buffalo Chicken Dip

Medical review February 2015.

Foods for Soy Allergy or Soy-Free Diets

Question

Could you please give a listing of foods for soy allergy or a soy-free diet? Also, could you provide guidance for the evaluation of a true soy (soy protein) allergy?

Richard R. Ramirez, MD

Response from James E. Gern, MD

Soy allergy can be difficult to deal with because of the large number of foods that contain soy protein. Soybeans are an excellent and inexpensive source of protein, which is why soy protein is added to so many foods. Soy can be added to wheat flour to boost the protein content “fortified flour,” and is thereby found in many baked goods, cereals, and crackers. It is the major source of protein in some infant formulas. In addition to these foods, soy is often found in such diverse foods as canned tuna, sauces, soups, and, of course, Asian food. The best way to identify soy-containing foods is to carefully read food product labels. Words such as “soy,” “soy protein,” “soy flour,” “shoyo (or shoyu) sauce,” “tofu,” and “miso” indicate the presence of soy protein. “Soy oil” listed as an ingredient is nonallergenic, as it does not contain protein. For additional information about food labels, refer to the Food Allergy & Anaphylaxis Network (www.foodallergy.org).

Evaluation of soy protein allergy generally involves carefully reviewing the history of adverse reactions to soy, and usually testing for the presence of allergic antibody (immunoglobulin E) directed against soy protein. The most common form of soy allergy produces symptoms soon after this protein is eaten, and the reactions generally involve the skin, gastrointestinal tract, and respiratory tract. More severe reactions can also affect the heart and blood pressure. If soy allergy is suspected, I would recommend seeking the help of an allergist to evaluate the history and test for soy-specific IgE.

Soy Milk: A Bowl Of Froot Loops In Every Glass?

I was in Starbucks recently (I try to avoid it, but its always “right there” and so too, mid morning, is my need for caffeine). “Are you lactose intolerant?” I asked my friend as she poured soy milk into her coffee. “No”, she shrugged, ” I just don’t think cow’s milk is good for you.” “Hmm”, I said, unscrewing the silver thermos of Whole Milk.

It’s not that I’m opposed to “the other white milk”, it’s just that I think we’ve been co-opted into believing that cow’s milk is bad, while alternative milk, the surest path to health salvation. (At last count there was soy, rice, almond, oat, hazelnut, coconut and hemp milk.)

To see if I was making too big a deal of this, I went to Whole Foods with a measuring tape. (As one does.) Amount of shelf space allocated to alt-milk – 80 sq. feet. Dairy milk – 20. Four times as much space for alt-milk! Granted this was a highly unscientific study conducted with a flimsy measuring device and because they are frequently replenishing the perishable dairy milk, they could be selling more than alt-milk, but still – four times!

Trends aside, what’s on the inside?

  • Soy milk contains a ton of added sugar. (Unless it’s “unsweetened”). Fruit Loops has 12g of sugar per cup – so does West Soy Organic Original*. If you’re drinking Chocolate flavor, eat a Hershey’s bar instead (24g of sugar vs. 23g in a cup of ZenSoy Chocolate.)
  • The majority of calcium is added. (There is some disagreement as to whether added calcium is as well absorbed as naturally-occurring, but I am of the belief that what’s added by a processor is never as good as what’s added by nature.)
  • Vitamins D, E and A are all added (none is naturally occurring).
  • Protein level is comparable to cow’s milk (about 8g/cup), but read the ingredients to see if soy protein isolate is added. SPI is an extracted and highly processed form of soy protein.
  • Some brands contain flavors (both natural and artificial) as well as additives.
  • Many of the cheaper and non-organic brands use beans processed with hexane (a petroleum derivative).

Find your brand on this chart.
You might also want to look for your brand here. The Cornucopia Institute considers not the micro nutritional info, as I did, but the broader corporate practices (including the use of hexane, as referenced above).

If you drink, drink responsibly

If you’re vegan, lactose intolerant or grossed-out by the idea of humans drinking another mammal’s milk, then drink soy (or another alt-milk), but if nothing else, be aware of the sugar and choose an organic, premium priced brand.

If you need a hint of sweet, either dilute the sweetened version with unsweetened, or add a touch of honey or agave to the unsweetened (toss it in a blender for better mixing).

Wondering about other health issues around soy? See this post where that’s addressed.

I have a soft spot for cows and would hate to see them out of work, so until I bow to pressure, cow’s milk (the kind from my local farmer- except for those occasional times at Starbucks) is going in my coffee.

And you? Alt-milk? Or are your loyalties with the cow.

Tofu: White Bread Of The Soy World?
What’s Not In Your Organic Milk That Should Be
What Children Get From Milk That You Don’t

*Cow’s milk also has 12g, making it not a low sugar product, but lactose is absorbed slightly more slowly than glucose (added to most soy milks). Moreover, the sugar in milk is naturally occurring, while the higher fat in whole milk helps slow the absorption of the sugar.

This Type of Non-Dairy Milk is the Healthiest, Study Says

That almond milk latte may be delicious, but a study just published in the Journal of Food Science and Technology suggests that the trendy beverage also has some drawbacks. When researchers compared the nutritional profiles of four popular “alternative” milks, they found that soy milk came out on top—and that almond, rice and coconut “milks” all lacked essential nutrients important for overall health.

Plant-based “milks” are often marketed as wholesome and appropriate substitutes for the real thing. To find out if these claims measured up, scientists at McGill University in Canada studied the nutrition labels of several unsweetened almond, soy and rice milks, plus coconut dairy-free beverages, on grocery-store shelves.

Cow’s milk, the researchers say, is still the most complete and balanced source of protein, fat and carbohydrates. Soy milk, a popular alternative option for more than four decades, was found to be the most comparable to cow’s milk in terms of overall nutrient balance. It’s also the highest in protein of all the alternative milk options studied, with about 7 to 12 grams (and about 95 calories) per 8-ounce serving.

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Soy milk also contains phytonutrients known as isoflavones, which have been shown to have cancer-fighting properties. It’s not a perfect substitute, though; some people complain about its “beany flavor,” the authors wrote, and some scientists have expressed concerns about “anti-nutrient” substances naturally found in soy, like phytic acid, which can make it harder for the body to absorb and digest important vitamins and minerals.

Almond milk, on the other hand, is low in calories (about 36 per serving) and rich in monounsaturated fatty acids. Getting more of these healthy fats may be beneficial to weight loss and weight management, the authors wrote, and they have also been shown to reduce LDL—or “bad”—cholesterol. But almond milk is also low in protein and carbohydrates, making it less nutritionally balanced than cow or soy milk.

Meanwhile, dairy-free coconut beverages have no protein. And although it’s low in calories (about 45 per serving), most of that energy comes from saturated fat. On the plus side, the report states, drinking this type of beverage has been associated with increases in HDL—or “good”—cholesterol and reductions in LDL cholesterol.

Sweet-tasting rice milk can serve as an alternative for people with allergies to soybeans and almonds, but it’s high in calories (133 per serving) and relatively low in beneficial nutrients. Research suggests that “consumption of rice milk as an alternative to cow’s milk without proper care can result in malnutrition,” the authors wrote, “especially in the case of infants.”

MORE: The Case Against Low-fat Milk Is Stronger Than Ever

Cow’s milk, by comparison to the dairy alternatives, contains about 158 calories per 8-ounce serving, along with 8 grams of protein, 9 grams of fat (5.5 of it saturated fat), and 11.5 grams of carbohydrates. That’s the “perfect composition of nutrients” for baby cows, the authors wrote in their paper, and it’s similar to the composition of human breast milk.

Milk is also an important source of vitamins and minerals—including calcium, which the body needs for bone health, especially during childhood and adolescence. Most milk substitutes are fortified with calcium to mimic the levels in cow’s milk, although the authors point out that “further research is needed to establish the consequences of added calcium in the human body.”

So why the need for alternatives? For one, dairy is one of the most common allergens among infants and children. Between 2% and 4% of children have a milk allergy (that’s more than peanuts or tree nuts), although as many as 80% may outgrow them by age 16. Plus, milk—especially raw, unpasteurized milk—has been linked to outbreaks of pathogens such as salmonella and E. coli around the world, suggesting that it’s not always the safest beverage for children or for adults.

Then there’s the issue of lactose intolerance. Somewhere between 15% and 75% of adults—depending on race, food habits and gut health—lack sufficient amounts of the enzyme needed to properly digest dairy products, according to the report. It’s even been estimated that up to 80% of people of African origin, and up to 100% of people of Asian and Indigenous American origin, are lactose intolerant.

Finally, while studies suggest that dairy products—even full-fat versions—can be a healthy part of a balanced diet, some people may not want to overdo it on high-calorie, high-fat cow’s milk. For all of these reasons, the authors say, consumers should know how popular milk substitutes compare.

“It is quite clear that nutritionally soy milk is the best alternative for replacing cow’s milk in human diet,” they concluded in their paper. They acknowledge, though, that more people may enjoy the flavor of almond milk. Those who choose the latter should make sure they’re getting enough essential nutrients, like carbs and protein, through other sources in their diet, they write.

That should be easy enough for adults, says lead author Sai Kranthi Kumar Vanga, a PhD candidate in McGill’s department of bioresource engineering, since they can also get protein from meats, nuts and beans, and healthy fats from sources such as olive oil. It can be more difficult, he adds, for babies and young children with dairy allergies. “Parents have to monitor their diet and provide them with appropriate alternatives for the lost nutrients, which is not easy,” he wrote in an email.

And while swapping out a few tablespoons of milk in your coffee every day won’t make a big difference in overall nutrition, Vanga says there could be implications for adults who consume considerably more milk—like every morning with their cereal. “Just replacing your cow’s milk with one of the plant-based milks and assuming it’s fulfilling the nutritional requirement could lead to health complications in the long run,” he says.

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