Soy products are all the rage and soy seems to be popping up on the ingredients list of almost every product. Soy is an alternative to meat, a substitute for dairy, a great crop for resting soil, and some say soy has the ability to end world hunger! However, along with all this hype there is controversy. Soy products contain phytic acid, trypsin inhibitors, lysinoalanine, nitrosamines, and phytoestrogens. If you do not know how these things affect the human body don’t worry - neither did I!
Phytic acid is a chelator, which means it can prevent the body from accessing minerals found in foods like calcium, magnesium, iron, and zinc. Phytic acid can contribute to mineral deficiencies; however phytic acid also helps to prevent osteoporosis. Phytic acid is considered to be a ‘beneficial phytochemical’ because “it also acts as an acid, chelating the vitamin niacin, which is basic, causing the condition known as pellagra (http://en.wikipedia.org/wiki/Phytic_acid).” When phytic acid is present in some of the foods eaten as part of a well balanced diet it appears that the positives outweigh the potential negatives.
Trypsin inhibitors stop trypsin from being secreted in the duodenum. Our bodies use trypsin to break down proteins into amino acids. This is necessary in order for the body to absorb protein from foods (http://en.wikipedia.org/wiki/Trypsin). Trypsin inhibitors can reduce the nutritional value obtained from foods.
Lysinoalanine is an unusual amino acid that is found in the proteins of cooked foods. It is formed when foods are “heated or treated with alkali” (http://www.mondofacto.com/facts/dictionary?lysinoalanine). Lysinoalanine has been labeled as a nephrotoxin which means it is damaging to the kidneys, however this was only a result of a study conducted on lab rats. When the study was conducted on mice, hamsters, rabbits, quail, and dogs or monkeys the same renal activity did not occur. It is suspected that this negative reaction to lysinoalanine is species specific (http://www.mondofacto.com/facts/dictionary?lysinoalanine).
“Nitrosamines are produced from nitrites and secondary amines, which often occur in the form of proteins (http://en.wikipedia.org/wiki/Nitrosamine).” Nitrosamines are considered to be carcinogenic which means they promote the formation of cancer (http://en.wikipedia.org/wiki/Nitrosamine).
Most of the debate over soy products revolves around phytoestrogens. It has recently been discovered that phytoestrogens disrupt endocrine function and have a negative effect on the thyroid. However, products containing phytoestrogen have only proven to be a problem when they are consumed in large quantities or when the diet is composed of solely phytoestrogen containing foods such as in the case of infants given soy formula. The premature development of females and the underdevelopement of males have been linked to the use of soy formula (http://www.soyonlineservice.co.nz/).
Phytoestrogens are able to mimic estrogen, but also “sometimes act as antagonists” and block estrogen (http://en.wikipedia.org/wiki/Phytoestrogens). Phytoestrogen tends to mimic estrogen in small doses and block estrogen in when taken in higher doses (http://envirocancer.cornell.edu/FactSheet/Diet/fs1.phyto.cfm).
Phytoestrogens may help to prevent some cancers, cardiovascular disease, menopausal symptoms, and osteoporosis (http://en.wikipedia.org/wiki/Phytoestrogens).
Phytoestrogens can lower testosterone levels in males leading to a lower sperm count and thus decreased fertility. However a study with rats indicated that reduced fertility due to exposure to phytoestrogen was only significant during short term intervals (http://www.publish.csiro.au/?act=view_file&file_id=SRB03Ab52.pdf). Regarding women’s health, “higher exposure to estrogens over a lifetime is linked with increased breast cancer risk (http://envirocancer.cornell.edu/FactSheet/Diet/fs1.phyto.cfm).”
Soy products are best consumed in moderation to obtain the benefits they offer without any of the potential negative consequences. So while soy is healthy it is probably best to make sure that our diets do not consist mainly of cereals with soy, soy energy bars, soy milk, and tofu! The cliché phrase “everything in moderation” seems to be inescapable! If we ignored the positive benefits of foods and only paid attention to potential risks when eating large quantities of something we would probably not be left with anything to eat! Although I fully intend to continue consuming soy products I will be more careful about how much of them I consume on a day to day basis.
One thing is for sure, soy is definately not a good candidate for solving world hunger! If it were consumed alone as a main food source it could be detrimental to everyones health.
