The Big Soy Controversy!
People often question me about The Big Soy Controversy. Many people hear half-truths about soy and use these as an excuse not to try plant-based eating.
There is a plethora of soy misinformation, and I’d like to counter this with some truths.
Firstly let me start by saying that the largest consumers of commercially grown GMO soybeans, both in the US and globally, are farmed animals. Yes, that is right, approximately 85% of all GMO soybeans end up in farmed animal feed, so if you are eating animal products then that GMO soy is on your plate (and subsequently in your body).
Soybean crops date all the way back to the 11th century BC and are native to East Asia. So it’s no surprise that Asian cultures are known as innovators when it comes to soy products. Common soy products are miso, tofu, tempeh, edamame and soy milk.
Soybeans are nutrient-dense and pack a punch in the protein stakes at 41% – therefore ranking right up there with milk, beef, and egg proteins. Soy is a ‘complete’ protein containing all the essential amino acids as well as an impressive array of micronutrients including calcium, iron, magnesium, manganese, phosphorus, potassium, vitamins B1, B2, B3, B5, B6, B9, C, and zinc! The dietary fat ratio is great too with a 1:7 ratio of omega-3 to omega 6. Soybeans are abundant in fibre and starches, which is beneficial for gut health and growth of healthy bacteria.
Despite the powerful health benefits of whole soy foods, there remains so much misinformation, confusion, and controversy regarding the so-called ‘dangers’ of soy consumption. I’ve discussed below some of the common misconceptions.
All soy is GMO
Soy directly consumed by humans (i.e. non-GMO soy foods such as tofu, tempeh, and soy milk) is widely available in supermarkets and is clearly labelled non-GMO. Factory-farmed animals, on the other hand, are fed 85% of the world’s GMO soy crops – so if you consume animal products you are indirectly consuming GMO soy.
Soy causes cancer
Misinformation regarding soy’s relationship to cancer largely stems from confusion about the phytoestrogens in soy. What you need to remember is that phytoestrogen is not estrogen. Both estrogen and testosterone are steroid hormones, occurring naturally in both genders of humans, as well as farmed animals. Estrogen at high levels can encourage cells to multiply more than they usually would, which could lead to an increase in cancer risk.
While soy does not contain estrogen, animal-derived foods do. You may be aware that animals used for meat and dairy are commonly supplemented with synthetic growth hormones, however many consumers don’t consider that animal flesh and cow milk also contain their own naturally occurring estrogen – and this is true even of ‘grass-fed’ and ‘organic’ animals.
Research studies have shown that higher rates of soy intake are associated with lower rates of breast cancer. There have also been ‘promising’ results from multiple animal models, demonstrating a reduction in tumor size with consumption of soy protein.
The body of research surrounding soy consumption is forever increasing so it would bode well to stay abreast of latest studies and use a critical mind to assess the results and who has funded the research.
Soy consumption can result in ‘Moobs’ (man boobs)
‘Moobs’ is another of the heavily circulated soy myths with no actual basis in scientific fact. Once again the ‘soy leads to man boobs’ myth is rooted in confusion surrounding estrogen and phytoestrogen. Phytoestrogen is not estrogen. Clinical studies in men show that isoflavones do not affect testosterone levels or circulating estrogen levels. Even at levels of isoflavone exposure significantly higher than those of a typical Asian male consuming a soy-rich diet, isoflavones have not been found to have feminising effects.
Soy negatively impacts thyroid function
The thyroid gland has the essential function of controlling metabolism. There are many dietary nutrients required for the optimal production of the thyroid hormone, iodine being the most widely recognised. The relationship between soy consumption, iodine deficiency and goiter (enlarged thyroid) was first described in 1960 in The New England Journal of Medicine. Infants consuming nonfortified soy-based formula developed goiter, yet the exact nature of the relationship was unclear. Numerous recent studies have disproven the causal relationship between soy and thyroid toxicity.
Soy is not healthy
Soy has been a major staple in Asian cultures for hundreds of years. If we look towards Asia for some health indicators we find their incidence of coronary artery disease, hypertension, ischemic stroke, hormone-dependent cancers, osteoporosis, postmenopausal hip fracture, diabetes, and obesity are all markedly lower than what is seen in the US.
We should listen to the fear mongering
The meat, dairy and egg industries stand to loose a lot if people start switching over to plant-based soy options for their dietary protein requirements. Much of the soy myths and hysteria is a direct result of misinformation disseminated by Weston A. Price Foundation’s (WAPF) relentless anti-soy campaigns. The WAPF is registered as a nonprofit organisation, but in reality is a multimillion-dollar operation that lobbies for raw milk and grass-fed beef. Its members (often farmers) make financial contributions to the organisation. One of the WAPF’s ongoing strategies for promoting animal farming interests is a concerted effort to discredit veganism in general and soy in particular. The WAPF actively publishes articles which propagate the supposed dangers of soy consumption, citing clinical and medical journals in an attempt to appear credible.
As with all foods, processed foods should be consumed in moderation. Unfortunately, refined soy foods – things like soy concentrates, textured soy, soy lecithin, etc. – are finding their way into more foods on supermarket shelves, and sadly many food manufacturers add processed soy as an ingredient to their products (both plant-based and animal-derived).
In a nutshell, whole soy foods are safe and nutritious. They can be a delicious addition to your diet. Buy the organic, non-GMO option where possible – they are easy to find and clearly labelled. If you have tried tofu in the past and have yet to fall in love, then I urge you to try again. Tofu is amazing – so versatile, nutritious, delicious, and the perfect meat replacement in all your favourite meals. Supermarkets are brimming with organic, non-GMO tofu, tempeh, and soy milk options, so throw some in your trolley and give it a go.
Tucker, Katherine L. et al. “Simulation with Soy Replacement Showed That Increased Soy Intake Could Contribute to Improved Nutrient Intake Profiles in the U.S. Population.” The Journal of Nutrition, doi: 10.3945/jn.110.123901; 27 October 2010
Morito, Keiko. et al. “Interaction of Phytoestrogens with Estrogen Receptors Alpha and Beta.” Biological and Pharmaceutical Bulletin, Vol. 24, Issue 4, pp. 351-356, April 2001
Messina, Mark. “Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence.” Fertility and Sterility, Vol. 93, Issue 7 , pp. 2095-2104, 1 May 2010
Chang, Hebron C. et al. “Dietary Genistein Inactivates Rat Thyroid Peroxidase in Vivo without an Apparent Hypothyroid Effect.” Toxicology and Applied Pharmacology, Vol 198, Issue 3, pp. 244-252, 1 November 2000
Wilson, Holly, MD. “A Vegan Doctor Addresses Soy Myths and Misinformation.” https://freefromharm.org/health-nutrition/vegan-doctor-addresses-soy-myths-and-misinformation/. 14 January 2014
Lee, Sang-Ah. et al. “Adolescent and Adult Soy Intake and Breast Cancer Risk: Results from the Shanghai Women’s Health Study.” The American Journal of Clinical Nutrition, Vol 89, Issue 6, pp. 1920-1926, June 2009
Wu, A H. et al. “Epidemiology of Soy Exposures and Breast Cancer Risk.” British Journal of Cancer, Vol 98, Issue 1, pp. 9-14, 15 January 2008
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