We have had quite a few of you ask why we allow soya in our book Sugar Free. Here Registered Dietician Tamzyn Campbell explains why.
By Tamzyn Murphy Campbell (Sugar Free Dietitian)
BSc, BSc Med(Hons) Human Nutrition and Dietetics, RD
The Real Meal Revolution cautions against soy, saying:
“99% of all soy is GMO, and is among the highest contaminated by pesticides of any crop. Soy seriously interferes with thyroid function and disrupts hormones. Antinutrients block the action of trypsin and other enzymes, imperative for protein digestion (not deactivated by cooking or processing) and may cause pancreatic cancer. Haemagglutinin is present, a blood clot-promoting substance (think stroke/heart attack). High in phytic acid (blocks uptake of essential minerals in the body) and in aluminium leached from processing tanks – soy should be avoided.” Reference: http://realmealrevolution.com/real-thinking/the-five-worst-and-five-best-foods-for-you.
I would agree that for non-vegetarians it’s easiest to avoid these often pesky legumes. However, for vegetarians, this recommendation can make it difficult and sometimes almost impossible to follow a Banting diet. I feel that vegetarians shouldn’t be excluded from reaping the health benefits associated with a low carb, high fat diet, just because they refuse to eat animals. As such, in Sugar Free, we have included soya as an option for this group, WITH certain very important caveats, to ensure that they avoid the negative health effects of soya while enabling them to reaps it’s potential benefits. The caveats are as follows:
- Ensure the soya you choose is NOT GMO. 99% of Soya is GMO (a genetically modified organism), so unless the soya you buy clearly states that it’s not GMO, don’t buy it. Organic soya beans are not GMO.
- Only eat a maximum of 2-4 soya servings daily. This ensure that you are not ingesting excessive isoflavones (phytonutrients with estrogenic effects) or omega-6 fatty acids (essential polyunsaturated fats with pro-inflammatory effects). Low doses of soy isoflavones and omega-6s, provided by this amount of soya, are actually beneficial to health. Higher amounts are not. (1 serving = ¼ cup cooked soya) Reference: Messina M & Messina V. The Role of Soy in Vegetarian Diets. Nutrients. 6 Aug 2010;2:855-88 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257705/
- Pre-soak, sprout and ferment your soya beans, or pre-soak and cook them properly: Phytic acid and other anti-nutrients are contained in soya, as well as in other legumes (e.g. beans, peas, lentils), grains, and even in nuts, seeds and, to a lesser degree in many vegetables (that doesn’t mean we should stop eating nuts, seeds and vegetables!). There are two main options to eliminate anti-nutrients in soya beans and other legumes. 1. Soak them in warm or room temperature water, acidified with vinegar or lemon juice, for 12 hours, then drain and rinse and repeat twice (totalling 36 hours of soaking time). After soaking, thoroughly cook your beans (roasting at a high temperature or long wet-cooking methods for longer periods are also fine). 2. Alternatively and preferably, soak your soya beans for 12 hours, then germinate them for 3-4 days, and finally, ferment them. Both methods completely inactivate phytic acid and other anti-nutrients in the soya beans. Haemagglutinin (a blood clot-promoting anti-nutrient in soya) is completely destroyed after 5 minutes of cooking at 100 degrees Celsius. References: Nagel R. Preparing Grains, Nuts, Seeds and Beans for Maximum Nutrition. Western A Price Foundation. 26 Mar 2010 http://www.westonaprice.org/health-topics/living-with-phytic-acid/; and Hussein L, El-Saied HM, Abu-Salem F. Some factors affecting the haemagglutinin of soybean. Zeitschrift für Ernährungswissenschaft. Dec 1980;19(4):233-7http://link.springer.com/article/10.1007/BF02023781
- Eat soya in its natural forms (e.g. beans, tempeh, tofu, natto), NOT processed soy products: The adverse effects of soya have been found when very large quantities are eaten or when people eat processed soy protein isolates. Contamination with aluminium happens during processing in tanks. Soy protein isolates have been linked to impaired thyroid function and pancreatic cancer. Natural forms of soya have not. In fact, studies have found that soya may actually be protective against cancers, including prostate cancer (when eaten in moderation). References: Nichols K & Williams J. The Soy Controversy. Huff Post Healthy Living. 24 Aug 2010 http://www.huffingtonpost.com/katherine-nichols/the-soy-controversy_b_689459.html? ; and Gonzales JF,Barnard ND, Jenkins DJ, et al. Applying the precautionary principle to nutrition and cancer. J Am Coll Nutr. 2014;33(3):239-46. doi: 10.1080/07315724.2013.866527. http://www.ncbi.nlm.nih.gov/pubmed/24870117; and Suzuki R, Kang Y, Li X, et al. Genistein potentiates the antitumor effect of 5-Fluorouracil by inducing apoptosis and autophagy in humanpancreatic cancer cells. Anticancer Res. 2014 Sep;34(9):4685-92. http://www.ncbi.nlm.nih.gov/pubmed/25202045; and Wang Z, Desmoulin S, Banerjee S, et al. Synergistic effects of multiple natural products in pancreatic cancer cells. Life Sci. 2008 Aug 15;83(7-8):293-300. doi: 10.1016/j.lfs.2008.06.017. http://www.ncbi.nlm.nih.gov/pubmed/18640131; and Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature. Thyroid. 2006 Mar;16(3):249-58. http://www.ncbi.nlm.nih.gov/pubmed/16571087
If you would like to buy a copy of ‘Sugar Free: 8 weeks to freedom from sugar and carb addiction’, you can do so here.