Soy: Dispelling the Myths
Infinity2 Research Department
There are many myths and misunderstandings about soy and protein that exist in the marketplace today. Most of this information has been perpetuated on the Internet and is often promoted by groups with a political or business agenda. Unfortunately, these myths and misunderstandings have caused confusion for the general public about the benefits of consuming a quality soy protein product. This paper is designed to address the most common myths and misunderstandings about soy protein and provide information from scientific research papers to explain the reality and truth about the benefits of soy as a high quality source of protein.
Myth: Soy is a poor quality protein.
Reality: Soy is the Only Plant
Protein Considered to be a Complete Protein
Most plant proteins have insufficient amounts of one or more of the essential amino acids. Grain products are usually deficient in lysine, whereas the legumes are low in methionine. An exception to this generality is the protein isolated from soybeans, which is comparable to animal protein in its amino acid content.
The nutritional quality of any protein relates to its amino acid composition, digestibility, and ability to supply the essential amino acids in the amounts required by the species consuming the protein. A complete protein is one that provides all of the essential amino acids. The soy protein isolate used by Infinity2 is a high quality, complete protein. It contains all the indispensable amino acids in concentrations sufficient to meet the requirements of humans. Infinity2’s soy protein isolate has a PDCAAS (Protein Digestibility Corrected Amino Acid Score) of 1.0. This is the highest possible score and means it has the same quality protein as meat, egg, and milk protein. It meets or exceeds the essential amino acid requirement of children and adults.
Myth: Soy is not a good protein
source for athletes or building muscle.
Reality: Soy Has a Higher Concentration of the Amino Acids Required for Building Muscle Than Whey, Casein or Egg.
People under conditional stress, such as athletes and people with an active lifestyle, will benefit from the branched chain amino acids and other important amino acids found in isolated soy protein. The amino acids that make up the ‘critical cluster’ of amino acids for athletes include the branched chain amino acids (leucine, isoleucine and valine) as well as glutamine and arginine. Each of these amino acids is required in greater amounts during training, but glutamine and arginine are particularly important. Studies have shown that the arginine plays a key role in stimulating the release of anabolic hormones that promote muscle formation, while glutamine buffers lactic acid, boosts protein synthesis and improves immune function.
Infinity2’s soy protein has higher concentrations of these amino acids than whey, casein, egg or beef protein. Infinity2’s soy protein is also a good source of all three Branch Chain Amino Acids used as energy during exercise. Per 100 grams of protein, the soy protein isolate used by Infinity2 delivers 36.2 grams of the ‘critical cluster’ of amino acids.
Soy protein also has the added benefit of providing specific bioflavanoids (isoflavones) that have been shown to enhance antioxidant potential in blood and reduce exercise induced muscle injury.(18)
Myth: Soy is hard to digest.
Reality: The Digestibility Score For Soy Protein Isolate Is 97% and Soy has the Highest PDCAAS Score Possible.
While raw soybeans may be hard to digest, this is not a true statement for soy protein used in products such as The Enzyme Diet™. The components of soy that are ‘hard to digest’ are the same fiber and carbohydrate components found in other beans/legumes. These components are present in only minimal amounts in soy protein used in powdered beverages, so this statement is not true for most soy protein products. The soy protein used by Infinity2 is 97% digestible and has a PDCAAS score of 1.0 – the highest possible.
Myth: Soy is highly allergenic.
Reality: Less Than 1% of the Population is Allergic to Soy
Isolated soy protein does not present any unusual risks of allergenic responses. Soy protein is less allergenic than cow’s milk (8). Allergy to cow’s milk is reported to range between 0.3 and 7.5 percent (1), whereas allergy to soy is reported at approximately 0.5 percent (8).
Myth: All soy contains MSG, nitrite, nitrates, pesticides, lysinoalanine, aluminum and other chemicals that can be harmful.
Reality: The Infinity2 Soy Protein Does Not Contain Any of These Substances.
MSG
Occasionally people are confused regarding the difference in glutamate (glutamic acid) and MSG – monosodium glutamate. The two are quite different. Glutamate is classified as a nonessential amino acid and is one of the most abundant naturally occurring amino acids in protein. Glutamate is found in soy protein isolate in concentrations similar to that of other protein foods. The concentration of glutamate in various commonly eaten protein foods is:
Whole milk 21.4g/100 g protein
Wheat flour 34.9g/100 g protein
Beef 15.2g/100 g protein
Soy Protein Isolate 19.1g/100 g protein
Monosodium glutamate (MSG), the monosodium salt of L-glutamic acid is widely used as a flavor enhancer all over the world. MSG is not a naturally occurring compound and consists of sodium and glutamate chemically bound together. MSG is produced through a fermentation process. MSG (Monosodium Glutamate) is not used as an ingredient, processing aid or additive in the production of the isolated soy protein used by Infinity2.
Nitrites and Nitrates
Nitrites and nitrates are formed when protein is heated under specific processing conditions. Nitrates and nitrites are commonly found in packaged meats such as hot dogs and luncheon meats. Infinity2’s soy protein is manufactured by water extraction of protein from defatted and dehulled soybean flakes, and retains the naturally occurring amino acids, vitamins, minerals and other phytochemicals. To ensure the quality of the product, the final soy protein isolate is tested to ensure there are no nitrates or nitrites present and to ensure that the essential amino acids and other nutrients remain active.
Lysinoalanine
Lysinoalanine is an unusual amino acid formed most often as the result of alkaline treatment of protein (6;7). Alkaline treatment is not used in the processing of the soy protein used by Infinity2 and tests of our soy have found no measurable lysinoalanine. Therefore lysinoalanine should not be a concern to individuals recommending or consuming Infinity2 products that contain soy.
Aluminum
Aluminum contamination is a common concern in the food
industry. When foods are processed in aluminum containers under acidic conditions, the aluminum can be leached from the container and contaminate the food. Infinity2’s soy protein in processed using a water wash, rather than an acid or alkaline wash to ensure that the product is not contaminated by aluminum. To further ensure quality, the finished protein is tested for aluminum and other contaminants to ensure product safety.
Pesticides
Infinity2’s soy protein, like all of our raw materials, is tested for
pesticides and other contaminants as part of our standard quality assurance program to ensure the safety and quality of our products. For more information on Infinity2’s manufacturing and quality
assurance, refer to the document titled “Manufacturing and
Quality Q&A”.
Myth: All soy contains enzyme inhibitors.
Reality: Any Enzyme Inhibitors Found Naturally in Raw Soybeans Have Been Removed From Infinity2’s Soy Protein.
Trypsin inhibitors (enzyme inhibitors) are naturally present in a variety of foods – soybeans, potatoes, peas, beans, peanuts, sweet corn, and other vegetables and cereals. In fact, raw potato contains twice the enzyme inhibitor activity of raw soy flour (17). Even when cooked, potatoes and hard-boiled eggs contain higher levels of trypsin inhibitors than toasted soy flours or soy protein isolates (17).
To ensure optimum digestibility and quality, Infinity2’s soy protein is carefully processed to decrease the trypsin inhibitor activity level to minimum levels. Any remaining soybean trypsin inhibitor is rapidly inactivated by normal human gastric juices as part of digestion and does not present any concern (12).
Myth: Soy contains growth inhibitors that stunt growth.
Reality: Children Fed Soy Grow Normally.
A review of the medical literature to date examining the effects of soy on growth was published in the 1998 issue of Nutrition Reviews. The author concluded that there is “no evidence of endocrine effects in humans from infant consumption of modern soy-based formulas. Growth is normal and no changes in timing of puberty or in fertility rates have been reported in humans who consumed soy as infants.” (11). The Journal of Pediatrics also conducted an earlier study that came to a similar conclusion (19).
Myth: Soy causes cancer.
Reality: Soy is Being Researched For It’s Potential Anti-Cancer Benefits and Has Been Used to Enhance the Beneficial Effects of Cancer Treatment Drugs.
There is absolutely no evidence that soy causes cancer. In fact, epidemiological studies have found that populations consuming higher amounts of soy protein in their diet have lower rates of various types of cancer, including breast cancer, colon cancer and prostate cancer. This observation has led scientists to conduct research into how and why soy may offer protective benefits against cancer. Dozens of research studies in both animals and humans have been conducted over the past decade in an attempt to uncover the component of soy that may be providing the protective effect. Some of these studies have even used soy protein to enhance the effects of cancer treatment drugs. Although scientists have not determined what factor may be providing the benefits, these studies have provided a considerable amount of data to support the theory that consuming soy protein may help reduce cancer risk (4).
Additionally, hundreds of studies have been conducted researching the potential benefits of soy protein for reducing heart disease risk, improving bone density and bone health and reducing the symptoms of menopause. There have been absolutely no scientific reports of soy protein increasing the risk of cancer (10).
Myth: Soy increases estrogen levels.
Reality: Studies Examining the Effect of Soy Protein on Hormone Levels Have Found Either No Change or a Decrease in Estrogen Levels in Humans.
The idea that soy increases estrogen levels comes from the use of the term “phytoestrogens”. Phytoestrogens are not actually estrogens; they are a specific class of bioflavanoids called isoflavones. These isoflavones are similar in structure to estrogen, but are not estrogen.
Contrary to what some Internet articles promote, studies that have measured the effects of soy protein containing isoflavones have found either no effect on estrogen and other hormone levels or a decrease in estrogen levels (13). A recent study published in January 2002 in the American Journal of Clinical Nutrition examined the effect of soy protein on the levels of endogenous hormones including estrogen. The researchers reported that “this study does NOT provide evidence that long-term ingestion of soy protein alters steroid hormone values” (15). The data in these studies also show “that neither isoflavones nor soy exert clinically important estrogenic effects on vaginal and other hormone-sensitive tissues” (5).
The studies that have found a decrease in estrogen levels with consumption of soy containing isoflavones have also noted an improvement in the ratio of the types of estrogens produced in the body and a decrease in the toxic estrogen metabolites (breakdown products) (20). Researchers propose that this effect may be what creates the potential cancer preventative effect of soy.
Myth: Soy reduces thyroid function.
Reality: Results from a number of clinical studies have failed to show clinically significant changes in thyroid function in either men or women with consumption of soy protein.
The notion that soy can cause thyroid disease stems from in vitro (test tube) and animal studies. These studies found that that genistein, one of the isoflavones in soy, can block the enzyme, thyroid peroxidase (TPO). TPO is the enzyme responsible for putting iodine on thyroglobulin (a thyroid protein) so it can make thyroid hormones. Blocking TPO activity decreases thyroid hormone production.
Although soy isoflavones have been shown to block TPO in vitro and in laboratory rats, these findings are not relevant to the safety of soy formulas for humans for several reasons.
1- Genistein only blocks TPO activity in iodine-deficient environments (2). It is rare that adults in modern countries, such as the U.S. are iodine deficient.
2- The animal studies examining the effects of soy on thyroid activity have used high doses of isoflavones. In fact, one research study (9) concluded, “soybean intake specifically interacts with iodine deficiency in induction of thyroid proliferative lesions in rats, only at high doses.” At lower amounts, no effect on thyroid function was observed.
3- Furthermore genistein is very similar in structure to bioflavanoids found in most fruits and vegetables. Bioflavonoids, in fact, are more potent inhibitors of TPO than genistein. If you’re going to argue that one shouldn’t be eating soy because it can compromise thyroid function, then we should also be arguing that none of us should eat fruits and vegetables because they might cause thyroid disease.
The bottom line is that in the normal case of iodine-sufficient individuals receiving intermittent or low doses of soy isoflavones, thyroid function is not affected (3). Results from a number of clinical studies have failed to show clinically significant changes in thyroid function in either men or women with consumption of soy protein.
The FDA supports consumption of soy protein and has approved a health claim stating that eating 25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Hundreds of human studies have shown the benefits of eating soy protein for heart disease, menopause, bone health and potentially cancer. Hypothyroidism has not been reported as a concern in these studies.
Myth: Soy Depletes Minerals Out
of the Body Due to High Phytic Acid Content
Reality: Phytic Acid is Present in
All High-Fiber Foods and Is Not a Toxic Chemical
Phytic acid is not a toxic chemical added to soy, nor is it something that is exclusive to soy. Phytic acid is actually a naturally occurring element of foods that is present in the bran or hulls of all seeds and grains (14). The concern with the phytic acid content of foods originates in its ability to bind the minerals (particularly iron and zinc) in foods and thereby block their absorption. When mineral absorption is blocked or decreased there is a risk of mineral deficiencies. Phytic acid or phytate cannot be broken down by the human digestive enzymes. Humans do not make the enzyme phytase that breaks down phytate. Phytase is however, made by yeast. When yeast is added to bread dough, the phytate is broken down by the phytase enzymes made by the yeast. This is why mineral deficiencies are common in areas of the world where unleavened bread (bread made without yeast) is consumed in high amounts. The unleavened bread does not have yeast added, so the phytate is still present in high amounts.
Although phytic acid content of foods can affect mineral
absorption, phytic acid is not toxic and it actually has some
beneficial properties. Phytic acid is a potent antioxidant and is the only antioxidant known that can completely counter the adverse effects posed by the hydroxyl radical, a free radical species involved in all cancers. Researchers are examining the possibility that phytic acid may be one of the primary components of soy that help to control cholesterol (16).
The phytic acid content of soy does not affect the absorption of the minerals in Infinity2 products because:
1- Infinity2 uses patented amino acid chelated minerals that are not affected by the phytic acid content of foods.
2- Infinity2 adds the enzymes necessary to ensure complete
breakdown of the whole food ingredients of its products, including soy.
The only way to completely eliminate phytic acid from your diet is to eliminate all high fiber foods, such as legumes and grains. Because it is well established that a diet high in fiber is beneficial to health, removing high fiber foods from the diet is not recommended.
Summary
In reviewing the scientific literature, we found hundreds of
published scientific studies on the health and nutrition benefits of soy. The FDA supports consumption of soy protein and has approved a health claim stating that eating 25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Hundreds of human studies have shown the benefits of eating soy protein for heart disease, menopause, bone health and potentially cancer. The reality is that the soy protein used by Infinity2:
• Is an excellent source of protein and is the only plant protein considered to be a complete protein.
• Has a higher concentration of the amino acids required for building muscle than whey, casein or egg.
• Is 97% digestible and has a PDCAAS (Protein Digestibility-Corrected Amino Acid Scoring) score of 1.0 - the highest possible.
• Is less allergenic than cow’s milk.
• Does not contain any MSG, nitrite, nitrates, pesticides, lysinoalanine, aluminum or other harmful chemicals.
• Does not contain enzyme inhibitors.
• Is safe for children to consume and does not affect their growth rates.
• Is being researched for its potential anti-cancer benefits and has been used to enhance the beneficial effects of cancer treatment drugs.
• Does not affect estrogen or other hormone levels.
• Does not affect thyroid function.
Soy is an excellent source of high quality protein. Soy is one of the oldest foods known to man, and has been a staple of Asian diets for centuries. It is a complete protein that provides all the essential amino acids your body needs.
Infinity2’s soy protein is the highest quality non-GMO soy protein available. The soy proteins are processed with a water wash (rather than the usual alcohol wash), which maintains the integrity of the naturally occurring amino acids, vitamins, minerals and other bioactive components. It is manufactured under strict specifications in order to guarantee a consistent, high quality product for our customers. Infinity2’s soy protein is lactose free and, unlike most soy protein on the market, Infinity2’s soy protein is from a non-genetically modified source (non-GMO). Infinity2’s soy protein exceeds industry safety, consistency and quality standards.
Infinity2 is not only dedicated to providing the highest quality products available, but Infinity2 also insists on providing scientifically accurate information for our customers. A list of scientific references for research on the benefits of soy protein is available upon request.
Reference List
1. Bahna, S. and D. Heiner. Allergies to Milk. New York, NY, Grune & Stratton. 1980, 7.
2. Chang, H. and D. Doerge. Dietary genistein inactivates rat thyroid peroxidase in vivo without an apparent hypothyroid effect. Toxicol Appl Pharmacol 168: 244-252, 2000.
3. Divi, R., H. Chang, and D. Doerge. Anti-thyroid isoflavones from soybean: isolation, characterization, and mechanisms of action. Biochem Pharmacol 54: 1087-1096, 1997.
4. Duncan, A. M., B. E. Merz, X. Xu, T. C. Nagel, W. R. Phipps, and M. S. Kurzer. Soy isoflavones exert modest hormonal effects in premenopausal women. J Clin Endocrinol Metab 84: 192-197, 1999.
5. Duncan, A., K. Underhill, X. Xu, J. Lavalleur, W. Phipps, and M. Kurzer. Modest hormonal effects of soy isoflavones in postmenopausal women. J Clin Endocrinol Metab 84: 3479-3484, 1999.
6. Feeney, R. Proteins for Humans: Evaluation and Factors Affecting Nutritional Value. Westport, CT, AVI. 1977, 233-254.
7. Finley, J. and M. Friedman. New Amino Acid Derivatives Formed by Alkaline Treatment of Protein in Protein Crosslinking, Nutritional and Medical Consequences. In Friedman, M., ed. Experimental Medicine and Biology. New York, NY, Plenum Press. 1977, 123-130.
8. Halpern, S., W. Sellars, R. Johnson, D. Anderson, S. Saperstein, and J. Reisch. J Allergy Clin Immunol 51: 139-151, 1973.
9. Ikeda, T., A. Nishikawa, H. Son, H. Nakamura, M. Miyauchi, T. Imazawa, S. Kimura, and M. Hirose. Synergistic effects of high-dose soybean intake with iodine deficiency, but not sulfadimethoxine or phenobarbital, on rat thyroid proliferation. Jpn J Cancer Res 92: 390-395, 2001.
10. Jenkins, D. J., C. W. Kendall, M. Garsetti, R. S. Rosenberg-Zand, C. J. Jackson, S. Agarwal, A. V. Rao, E. P. Diamandis, T. Parker, D. Faulkner, V. Vuksan, and E. Vidgen. Effect of soy protein foods on low-density lipoprotein oxidation and ex vivo sex hormone receptor activity--a controlled crossover trial. Metabolism 49: 537-543, 2000.
11. Klein, K. Isoflavones, Soy-based infant formulas, and relevance to endocrine function. Nutr Rev 56: 193-204, 1998.
12. Krogdahl, A. and H. Holm. Soybean proteinase inhibitors and human proteolytic enzymes: selective inactivation of inhibitors by treatment with human gastric juice. J Nutr 111: 2045-2051, 1981.
13. Lu, L, Anderson, KE, Nealton, W, and Nagamani, M. Reductions in Steroid and Gastrointestinal hormone levels in men and premenopausal women with soy consumption for one month. (oral abstract). 9-15-1996. Brussels, Belgium. Hormonal Effects of Soy - Premenopausal studies. 9-15-1996.
Ref Type: Conference Proceeding
14. Morris, E. R. An overview of current information on bioavailability of dietary iron to humans. Fed.Proc. 42: 1716-1720, 1983.
15. Perksy, V., M. Turyk, L. Wang, S. Freels, R. Chatteron, S. Barnes, J. Erdman, D. Sepkovic, H. Bradlow, and S. Potter. Effect of soy protein on endogenous hormones in postmenopausal women. Am J Clin Nutr 75: 145-153, 2002.
16. Potter, S. M. Overview of proposed mechanisms for the hypocholesterolemic effect of soy. J Nutr 125: 606S-611S, 1995.
17. Rackis, J., W. Wolf, and E. Baker. Protease inhibitors in plant foods: content and inactivation. In Friedman, M., ed. Nutritional and toxicological significance of enzyme inhibitors in foods. New York, NY, Plenum Press. 1986, 299-347.
18. Rossi, A., R. DiSilvestro, and Blostein-Fujii. Effects of soy consumption on exercise induced acute muscle damage and oxidtive stress in young adult males. FASEB J 12: A653, 1998.
19. Uauy, R., D. R. Hoffman, E. E. Birch, D. G. Birch, D. M. Jameson, and J. Tyson. Safety and efficacy of omega-3 fatty acids in the nutrition of very low birth weight infants: soy oil and marine oil supplementation of formula. J Pediatr 124: 612-620, 1994.
20. Xu, X., A. M. Duncan, K. E. Wangen, and M. S. Kurzer. Soy consumption alters endogenous estrogen metabolism in postmenopausal women. Cancer Epidemiol.Biomarkers Prev 9: 781-786, 2000.
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