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  • Paul Smith
    Paul Smith

    Soy as a Food Allergen

    Reviewed and edited by a celiac disease expert.

    Celiac.com 12/14/2009 - Soy is a food allergen and there are several main issues. Firstly, soy proteins, especially the trypsin inhibitor enzymes, along with the proteins in dairy products, wheat, peanuts, eggs, sesame seeds, shellfish and crustaceans, have a tendency to produce allergic reactions in susceptible individuals. However, all my reading and experience of soy, over 50 years, suggests that soy protein is somewhat milder in its action than the proteins in peanuts, eggs and sesame seeds. From a toxicological point of view and as reported by FSANZ, the presence of soy at less than 88 p.p.m. (parts per million) does not register for the vast majority of the population, whereas in susceptible individuals and by comparison, gluten, eggs and peanuts can all register adversely at or at less than 1 - 3 p.p.m. There is no history of severe anaphylaxis and sudden death associated with soy that I am aware of. However, there are a very few people who may experience flu and chronic fatigue and fuzzy headedness like symptoms from exposure to soy and these people are probably best to totally exclude soy from their diets. There are also some people who have a negative attitude towards soy who decline to eat soy, often without ever having tasted it or in response to a single bad experience. For many people brought up on cow’s milk soy is a difficult to acquire taste. Most people eat soy without any awareness of having done so.

    It is my belief that for most people a modest level of soy intake, including its protein provides a valuable addition to the diet without undue side effects. There are many people who tolerate soy, who experience difficulties with gluten, dairy, peanut and egg proteins, especially if the soy is introduced into their diets gradually. In commercial food production, soy protein is often used at fairly low levels as a dairy powder, cheese, egg and nut extender/substitute, for price, functionality, natural preservative/anti-oxidant/emulsification properties, natural colour and for nutrition reasons.

    Secondly, soy and other legumes contain natural oligosaccharides or complex sugars – principally stachyose, raffinose and vacchyose which consist of various combinations of galactose and glucose molecules – which human beings lack the enzymes to digest. These sugars ferment in the gut, rather than digest, producing gas, flatulence, stomach pains, bloating, diarrhoea and sometimes acute discomfort especially if the fermentation process occurs in the more restricted upper digestive tract. This is often crudely referred to as the “fart factor” and it is often far worse when there has been a rapid change of diet or an overly large amount consumed. There is also some evidence that fructose mal-absorption, for example, can lead to depression and interfere in menstrual cycles in young women. I believe this sugar factor in Soy may be of greater concern than the soy protein issue and one best considered within the FODMAPS (Fermentable Oligosaccharides (fructans, stachyose, raffinose), Disaccharides (lactose), Mono-saccharides (fructose), and Polyols (sorbitol, mannitol and xylitol)) Concept explored in Sue Shepherd’s recent PhD Thesis. Sue, who is both a celiac and a dietician, has taken a strong interest in this field because, along with diabetes, the fermentable sugars issue often overlaps and is associated with gluten sensitivity and celiac disease. These fermentation issues can appear in conjunction with or independently of any gluten issues. The gluten induced gut damage and nutrient mal-absorption exacerbating and feeding off the fermentation issue and vice versa. As with the reaction to gluten there is a wide range of sensitivity and responses to and between these different sugars with some people reacting adversely to all these sugars while others react to some and not others. The degree of and cumulative effects of exposure are also an issue. The response can also depend upon where in the gut the fermentation process occurs: there appears to be more pain if the fermentation occurs in the stomach or the small bowel rather than the colon. The fermentation may occur in one part of the gut, in all three parts or various combinations thereof. There is also some conjecture about the gut-brain axis over sending and misinterpreting the gut nerve signals. While Soy also contains a small percentage of fructose there is not sufficient present for this to become an issue. The fructose content of such staples as onions and garlic, for example, is of far more concern.

    Interestingly, neither the protein nor fermentable oligosaccharides appear to be an issue in tofu consumption, where only some of the protein and sugars are extracted from the soy. The fermentation processes used in the manufacture of miso and tempeh, two other traditional soy foods, also seem to overcome the soy protein and fermentable oligosaccharide issues. It appears that the protein and sugar hydrolysis processes that take place in the fermentation that occurs during the manufacture of these products breaks the proteins and sugars down to simpler, more digestible and assimilable forms making these foods easier to digest than, for example, a more minimally processed soy flour. It is also possible and may be desirable to look at fermentable sugar extraction or modification or enzyme or acid hydrolysis during the processing of many ingredients and products.

    The third issue with soy is the concentration of the naturally occurring soy phyto-estrogens or isoflavones (plant derived mimic female hormones) which may occur, particularly in the processing of soy isolates where the oil is extracted prior to precipitation of the protein and the skimming off of the carbohydrate/dietary fibre fraction. This produces a product with protein at 86%, moisture at 6% with low ash, fat, dietary fibre and carbohydrate levels where sometimes the isoflavones or phyto-estrogens are also extracted and sometimes not. Where soy isolates are being considered as the base for an infant formula it is extremely important to limit the intake of the phyto-estrogen or plant derived hormone to the absolute minimum. It is also important to note that dairy derived infant formulas also need to be highly modified to make them suitable for human babies.

    On another occasion, I was contacted by a young man who was using soy isolate (a concentrated protein) as a body building aid and his protein intake was equivalent to four times the recommended daily protein intake. He was depositing unwanted fat on his thighs and buttocks, his beard growth was patchy and thin – he was demonstrating female characteristics due to the high levels of female type plant hormones he was ingesting - and he was also experiencing genital and irritable bowel type symptoms and from what he said, I also suspect kidney problems. It is my belief that he was consuming excessive levels of protein and using a form of soy isolate which had concentrated rather than removed the phyto-estrogens. There is much to recommend moderation, diversity and balance in all areas of life: an informed dietary restraint enabling the body to take what it wants from the diet and to reject or handle the rest. Over consumption of any particular food has always been problematic no matter how innocuous that food may seem. We and our health reflect our eating and lifestyle habits.

    A fourth issue, is that the introduction of genetically modified organism (GMO) foods has brought further complications into this equation. Internationally, various crops including soy, cotton, canola and maize have been genetically engineered to resist the application of glysophate, a weed killer commonly known as “Roundup”, and to kill predatory insects through a built in pesticide in every plant. The writer believes there are serious moral, ethical, logic and safety issues involved in the use of such engineered foods, the benefits of which convey no positive health or nutritional value to the end consumer and which may yet prove detrimental to the consumers’ health and the environment.

    For example, Bt pesticide, which is produced from the natural soil bacteria Bacillus thuringiensis, is a potent poison which ruptures the stomachs of and kills any insects which may attack any crop engineered or treated with it. As an integral part of the plant what do these toxins do to the human intestinal tract? In the USA, there are concerns about possible genetically modified gut bacteria as a result of eating such genetically modified foods: about new and difficult to identify and trace immune system health issues. Fortunately, Australia has been slower in its adoption of these genetically modified crops and no genetically modified soybeans have either been allowed into or grown in Australia. Our company only processes Australian grown soy beans, and other non-GMO gluten-free grains and legumes.

    However, there are vast differences between the use of Bt spray and the far more concentrated systemic, engineered versions of this pesticide. The latter is an integral part of the plant and, unlike the spray, it cannot be washed off. In whatever form, Bt is a toxin and irritant with allergenic properties. Personally, I have serious reservations about these types of genetically engineered foods: the concept is obscene and I believe that such foods are inherently dangerous.

    Genetically modified soy and corn each contain two new proteins with allergenic properties. genetically modified soy has been found to contain higher levels of trypsin inhibitor enzymes (which are a known soy allergen) than conventional soybeans. Skin prick tests, in the UK and USA, have also revealed a more than 50 % increase in allergic reactions to genetically modified soy compared to the traditional product.

    There is an enormous, untested and long term potential for such genetically modified crops to create a host of poisoning, allergen, immune system, genetic aberration, genital deformity, fertility, genetically modified gut bacteria, digestive, eczema, inflammation and nutrition problems not to mention the possibility of new types of diseases. These genetically modified foods have been introduced by the same companies which developed DDT and Thalidomide. The fundamental question lingers: “have they got it right this time?” Unfortunately, it may take several generations for these associated problems to manifest themselves and to be identified, just as it did with DDT. Tracing the causes of and the treatment of these insidious problems may be difficult and expensive. In introducing these products we have ventured into the unknown, not only health-wise but nutritionally and legally.

    Despite all the above negatives, I still believe that whole bean soy foods eaten sparingly have an important place in a well balanced diet. Many other staple foods including eggs, wheat, gluten, peanuts, dairy products are equally, if not more, problematic just as some fruits and vegetables can be. At the end of day it is usually a question of the balance, of the degree of tolerance for and degree of exposure to each of these foods that is critical and this may vary from individual to individual. It is also my belief that a modest level of exposure is better than total exclusion. For example, I have a mucus issue with milk fat if I over indulge in dairy products but consumed sparingly I can enjoy a thin sliver of cheese without problem.

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    Soybean allergy is one of the more common food allergies, especially among babies and children. Approximately 0.4 percent of children are allergic to soy. Studies indicate that an allergy to soy generally occurs early in childhood and often is outgrown by age three. Research indicates that the majority of children with soy allergy will outgrow the allergy by the age of 10.

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  • About Me

    I am 60 years old. An Architect and Landscape Architect by training, graduating in both in 1974. I have an MBA (Master of Business Administration Degree) from Melbourne University in 1990. My family have owned FG Roberts (a gluten free/soy products factory in Melbourne Australia) for 54 years. I have been employed by the company full time since 1980 in various technical, management, operational, product development, research and marketing roles. My Web site is: www.glutenfreehealth.net

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