Despite being one of the most well researched foods on the planet, with abundant research supporting a myriad of health benefits, soy products continue to carry this stigma:
‘Don’t you know soy causes breast cancer?’
I’ve heard this so many times in my life. Mostly while sipping a lovely soy flat white, which suddenly tastes less lovely.
So are soy foods a healthy food choice, or should you avoid them?
Most evidence supports soy foods not just as a healthy alternative to dairy, but as a superfood in its own right.
Soy is a functional food containing compounds known to actively reduce symptoms and assist the prevention of many common chronic health conditions.
Decades of research supports soy consumption as beneficial for reducing risk of heart disease, obesity, diabetes, osteoporosis, kidney dysfunction, menopause symptoms and various types of cancer.
Given these conditions are the main causes of illness, mortality and health burden in the Western world, we really should take more notice.
Why do soy foods have such a bad reputation?
Mostly it’s because the ‘oestrogen-like’ effects of soy proteins drew attention to their impact on female hormones. Animal studies suggested a link between soy proteins and the formation and growth of breast and uterine cancers, but these results have not been extrapolated to humans. (Messina, 2016, ACS 2019, AICR, 2021, Nogueira-de-Almeida et. al, 2020).
It's important to note that a key reason for the intense study of soy foods was precisely the opposite. Soy has been studied for generations because the incidence of breast cancer in high soy-consuming countries has traditionally been much lower than in Western countries. Unfortunately, as Asian consumers have become ‘more Westernised’ so has their incidence of breast cancer (Messina, 2016).
In a final burst of myth busting, let’s refer to the updated statement from the American Cancer Society and American Institute for Cancer Research which says ‘soy foods can be safely consumed by women with breast cancer.’
For even more encouragement, The World Cancer Research Fund International has said ‘there is a possible link between consuming soy foods and improved breast cancer prognosis’ (Messina, 2016, ACS 2019, AICR, 2021, WCRF, 2018).
So that's sounding ever-more positive, right?
Now for the really good stuff: Nutrition based reasons soy foods are healthy foods:
· Soy is the only plant protein that contains the full amino acid profile
· Unlike animal protein, soy is very low in calories and low in saturated fat
· It’s an alkaline protein, so less inflammatory than animal protein too
· Soy is naturally high in calcium and iron
· It contains a favourable balance of Omega 3 and Omega 6 fats; a healthy combination lacking in the Western diet
Regarding the functional, disease preventing health benefits of soy foods:
Cholesterol heath: Consistently shown to reduce LDL (bad) cholesterol, improve HDL (good) cholesterol and reduce overall triglyceride (blood fats) levels.
Reduced risk of heart disease: Associated with reduced arterial stiffness, improved dilation of arteries for better circulatory flow and moderate reductions in blood pressure. Combined with improved cholesterol profile, it builds a strong case for heart health.
Kidney Health: replacing animal protein with soy protein shows benefits for kidney function and reduced inflammation
Diabetes: Regular consumption of soy foods may support healthier glucose tolerance, reduced insulin spikes and lower symptoms of Type II diabetes.
Osteoporosis and bone density: Soy isoflavones have a positive effect on bone mineral density and up to 33% risk reduction for bone fracture and osteoporosis.
Breast cancer: Despite the controversy, case control studies show higher soy intake early in life is associated with 25% to 60% reductions in risk (Messina, 2016)
Mental Health: studies show soy isoflavones support reduced depressive symptoms in depressed women. In some studies, the results were similar to the effect of Zoloft and Prozac (Messina 2016)
Gut Health: Soy improves favourable gut bacteria balance and is linked to higher numbers of the healthy bifidobacteria and lactobacilli microbes
Menopause: Soy foods are consistently shown to reduce the incidence and severity of hot flashes during and after menopause. It’s benefits for heart and bone health make it a powerful dietary choice for women.
(D’adamo, 2014, Messina, 2016, Wu, Zhang, Huang, Li, 2017, Nogueira-de-Almeida et. al, 2020)
So I DO recommend soy foods, with this VITAL caveat:
If you’ve done one of my programs you already know I ONLY recommend organic, non-GMO, whole soy foods. This includes:
· Firm and silken tofu
· Tempeh
· Natto
· Miso
· Tamari (gluten and additive-free soy sauce)
· Soy milk (brands that use whole soy beans no added sugars, oils or preservatives)
· And of course, edamame - actual soy beans
Healthy consumption of soy foods DOES NOT include the soy protein extracts mixed with emulsifiers and vegetable oils and salt used to bulk up packaged foods from jam to cakes, sausages or worse, soy-sages and other fake meats.
Those I do not recommend!
Enjoy your whole soy foods for all their healthy benefits, but be informed, wise and careful about the quality of your soy. As usual, wholefoods are the go.
When you should be careful eating soy products:
In conditions where thyroid dysfunction is present, but not diagnosed, eating soy may lead to the development of hypothyroidism. In treated thyroid conditions soy can be safely consumed 2 hours before or after medication.
Soy allergies exist too, as they can with any food. If you're allergic to soy, obviously you shouldn’t eat it!
Need a consult?
If you’re concerned about your healthy food choices, thyroid or food allergies, a nutrition consultation can help. Reach out here.
REFREENCES
American Government Publication. (2021), Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Retrieved 3 November 2021, from https://www.wcrf.org/
American Institute for Cancer Research. (2021). Soy: Intake Does Not Increase Risk for Breast Cancer Survivors. Retrieved 3 November 2021, from https://www.aicr.org/cancer-prevention/food-facts/soy/
Ahsan, F. (2018). Effects of Dietary Soy and Its Constituents on Human Health: A Review. Biomedical Journal Of Scientific & Technical Research, 12(2). https://doi.org/10.26717/bjstr.2018.12.002239
Cancer.org. (2021). Soy and Cancer Risk: Our Expert’s Advice. Retrieved 3 November 2021, from https://www.cancer.org/latest-news/soy-and-cancer-risk-our-experts-advice.html.
D’Adamo, C.R., Sahin, A. (2014). Soy Foods and Supplementation: A Review of Commonly Perceived Health Benefits and Risks. Alternative Therapies in Health and Medicine 20, (Suppl 1):39-51
Messina, M. (2016). Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature. Nutrients, 8(12), 754. https://doi.org/10.3390/nu8120754
Nogueira-de-Almeida, C., Ferraz, I., Ued, F., Almeida, A., & Ciampo, L. (2020). Impact of soy consumption on human health: integrative review. Brazilian Journal Of Food Technology, 23. https://doi.org/10.1590/1981-6723.12919
Wu, H., Zhang, Z., Huang, H., & Li, Z. (2017). Health benefits of soy and soy phytochemicals. AME Medical Journal, 2, 162-162. https://doi.org/10.21037/amj.2017.10.04
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