YASO - Soy like never before

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Fact: The FDA approved a health claim for soy and heart disease that states, ”25g of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease”, after reviewing extensive human research (FDA approves new health claim for soy protein and coronary heart disease. October 20, 1999. Accessed at http://www.fda.gov/ on January 8, 2007).

Fact: Side effects from soy are rare, but may include occasional intestinal problems such as bloating and stomach pain.

The digestibility of soy protein is limited by the presence of oligosaccharides such as raffinose, stachyose and verbascose. These are not metabolised by humans, because we do not have the alpha-galactosidase enzyme. Instead they are fermented by our gut flora, creating gas, which can cause flatulence, diarrhoea, and indigestion. This problem is considered to be the single most important factor that deters people from eating more beans or grain legumes. Germination is one of the most effective ways of eliminating some of these anti-nutritional compounds and enhancing the palatability of soy. (Pei-Yin Lin Bioactive Compounds in Legumes and their Germinated Products J. of Agricultural and Food Chemistry 54:3807-14, 2006). Thanks to being metabolised in the sprouting process, Yaso contains practically no stachyose.

Fact: Phytic acid, found in soy products, binds minerals, proteins and carbohydrates and can inhibit the absorption of calcium, magnesium, copper, zinc and iron.

Fermenting or sprouting the soy bean before cooking neutralizes a large portion of the phytic acid, releasing these nutrients for absorption in the body. The bioavailability of these minerals is much higher in Yaso compared to normal soy products.

Fact: The isoflavones naturally found in soy may benefit human health.

Soy and other foods contain numerous isoflavones, bioactive compounds that may improve the health of arteries, prevent certain cancers and reduce bone loss. Unfortunately, confusion arises from animal studies which test doses of isoflavones substantially higher than the amount of these compounds people consume in soy foods. Some animal studies have administered a very concentrated source of only one specific isoflavone, such as genistein, that differs from the array of isoflavones consumed in food. Humans metabolize soy isoflavones differently from animals. Applying results from animal studies to humans can be like mixing apples and oranges (Messina M, et al. Skeletal benefits of soy isoflavones: a review of the clinicaltrial and epidemiologic data. Curr Opin Clin Nutr Metab Care 2004, 7:649-58).

Fact: Isoflavones in soy foods have no significant effects on hormone levels in men or women.

Isoflavones are called ”phytoestrogens” because they look similar to the chemical structure of estrogens, but they act differently to oestrogen hormones in the human body.

The statement that soy isoflavones may have side effects on reproductive functions is based mostly on in vitro and rodent data.

Oestrogen plays many roles in men: regulating bone mineral density, controlling cholesterol and lipid levels in the blood, promoting sperm maturation. High levels of oestrogen in men can lead to gynecomastia (enlargement of breast tissue) and may also cause a decrease in testosterone (the male sex hormone). Soy isoflavones do not necessarily raise oestrogen. Isoflavones slightly increase the effects of oestrogens when oestrogen levels are low, and decrease when the oestrogen levels are high. There are no human studies that show consuming soy isoflavones significantly changes testosterone levels, sperm count or quality, or penis anatomy (NTP-CERHR Expert panel on the Reproductive and Developmental Toxicity of Soy formula. April 2006 http://cerhr.niehs.nih.gov-., DiSilvestro RA, et al. Soy protein intake by active young adult men raises plasma antioxidant capacity without altering plasma testosterone. Nutrition Research 2006; 26:92-95). A 2011 analysis of clinical data in the journal ”Fertility and Sterility” found no effects of soy products or isoflavones on male sex hormones in men compared to control group.

Fact: Soy foods do not affect a woman’s fertility and are safe to consume during pregnancy.

A scientific panel convened in March 2006 by the National Institute of Environmental Health Sciences in US, found that even pregnant women who eat soy regularly consume such low amounts of genistein, the most heavily concentrated isoflavone in soy, that the likelihood of reproductive or developmental effects are of ”negligible concern”. Any problems observed were in targeted animal studies, not human studies, using very large amounts of genistein.

Generations of Asians have regularly consumed soy foods and there have not been any increased medical reports of fertility disorders. Asian countries have produced very healthy children for centuries.


Fact: Soyfoods are safe to eat for women at risk of or with breast cancer.

Experiments with mice have found that very high levels of soy isoflavones are associated with tumours growing faster. When these studies are repeated in women, no link between eating soy and tumour recurrence or growth has been found. Mice and rats produce lower levels of hormonal oestrogen than women, and these animals metabolize isoflavones differently to humans. Relatively limited research has been conducted, and the clinical studies often involved small numbers of subjects. There is no evidence that isoflavone intake increases breast tissue density in pre- or postmenopausal women. The epidemiologic data are generally consistent with the clinical data, showing no indication of increased risk (Trock BJ, et al. Meta-analysis of soy-intake and brest cancer risk. J Nat Cancer Inst. 2006; 98:459-71.). As a precaution, those who are taking tamoxifen should ask their oncologist about soy and other nutrients, since animal studies have shown that large amounts of isoflavones from any source can alter the action of tamoxifen.


Fact: Soy foods have no significant effect on thyroid function in healthy people.

Excessive soy intake has been reported to be responsible for the development of goiter, including thyroid enlargement, in both iodine-deficient rodents and infants fed soy–flour-based formula without iodine fortification. However, it appears that consumption of soy could cause goiter only in animals or humans consuming diets marginally adequate in iodine or who were predisposed to develop goiter, and in most cases dietary supplementation with adequate iodine can reverse the disorders. In this observation iodine deficiency, rather than soy consumption, was to blame. A review of studies on healthy men and women with enough iodine in their diets found that taking soy foods or isoflavones had no or only very modest effects (but within normal range) on thyroid function. Several foods high in fibre, including soy foods, contain components that may affect medication for hypothyroidism (underactive thyroid). Some physicians suggest taking the medication between meals to avoid foods interfering with the medicine, but soy foods can be consumed safely (Messina M et al. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature. Thyroid. 2006; 16:249-59).


Fact: “The prevalence of soybean allergy in the general population is probably not higher than 0.2 % and could be as low as 0.1 % among the U.S. population. This likely prevalence for soybean allergy contrasts with prevalence estimates of 1.9 % for crustacean allergy, 0.6 % for peanut allergy, 0.5 % for tree nut allergy, and 0.4 % for fish allergy.” (SichererSH, Munoz-Furlong A, BurksAW, SampsonHA.J. AllergyClin.Immunol) Symptoms of an allergic reaction can be mild, such as sneezing or runny nose; or more serious, with rash, hives, itching, trouble breathing or swallowing. The sprouting process decreases the presence of allergenic proteins by 30-40%, so that Yaso is substantially less allergenic compared to the raw soybean. (Analysis performed by KEKI, Budapest 2012).