Not soy good for you: the beginners guide to the low down on soy

September 1, 2015





A word of warning about soy.


When patients present to me with hormonal imbalance symptoms, I will focus on the importance of optimising their diet, together with lifestyle changes and supplementation support.


Among the dietary spring clean from gluten, artificial sweeteners and sugar, soy products are one of the first foods I recommend to leave off of the plate (and glass).  Let                                        me explain why. 


Soy suppresses the function of your thyroid gland.


Soy is a type of food called a goitrogen. These foods compete with the uptake of iodine, an important mineral for the thyroid. Lower iodine levels lead to a sluggish thyroid gland, causing lowered levels of thyroid hormone available for the bodily functions, such as brain development, maturation, regulating temperature, energy levels and metabolism.


Even after fermentation, soy products can still disrupt thyroid function, so if you have an existing underactive thyroid condition, or thyroid issues run in the family, you are best to leave out all soy products.



Soy is oestrogenic.


Soy is a source of phytoestrogens, having the ability to boost oestrogen levels in the body. We are bombarded with so many oestrogen-mimicking substances in our environment and many oestrogen dominant signs, symptoms and conditions are presenting in women.


Acne, breast tenderness and mood swings before menstruation along with heavy, painful periods and conditions such as endometriosis and fibroids, are some common signs that oestrogen levels are likely to be at a dangerously high level.


Therefore, you should limit exposure of any food sources of oestrogens, such as soy.



Soy is often genetically modified.

“M​ore than 90% of the world's soy production is genetically modified, which is rarely labelled as such.” Dr Natasha Campbell- McBride states in her book ‘Gut and Psychology Syndrome’. (1 Pg. 114)



Soy contains enzyme inhibitors.


Soy contains Phytic acid. This binds to and prevents minerals from being absorbed. Unless ‘activated’, through a process of soaking the bean for 12 hours, or fermented, the phytic acid will act to block the absorption of minerals, such as zinc, calcium, magnesium and iron, in the small intestine. This contributes to deficiency states in the body.



Soy is allergenic.


Soy is a common allergen in the body, likely due to the recent increased use as a binding agent in processed foods (found on labels as Soy Isolate). Soy allergies can cause many side effects such as skin conditions (eczema), digestive upsets, behavioural issues, decreased mental function and respiratory congestion.



Soy Isolate is toxic.


Soy contains high aluminium and chemicals, such as nitrates (due to a commercial wash procedure to make it into soy protein isolate). Dr Natasha Campbell-McBride demonstrates in her book ‘Gut and Psychology Syndrome’, that up to 60 per cent of processed foods, including soy milk and soy infant formulas, contain soy protein isolate. (2 Pg. 113)  Scary stuff!



Try healthier alternatives.


In place of soymilk there are many delicious alternatives to try, without compromising your health. Try coconut, rice, nut or seed milks and as they all have a very different taste, if you don’t like one, keep trying. My favourites and coconut and almond milk.


In place of tofu, use eggs, nuts and seeds such as quinoa and buckwheat as your vegetarian proteins.  Organic natto, tempeh and tamari (wheat-free soy sauce) are healthier fermented soy options for you to try. 


Otherwise focusing on a wholefood based diet, making meals up from scratch, or purchasing home made items labelled as soy free, is an assurance that your food is free from the dangerous soy protein isolate.


Take care of your hormone health and embrace a soy-free diet today.



About Kasey:


Kasey is a qualified Naturopath and Nutritionist who runs a busy Adelaide based clinic ‘Aloe Health’. For Kasey, Nutrition is such a fundamental part of achieving true health. With a special interest in digestive and hormone health and through her clinic, speaking, writing and online projects, Kasey aims to educate many others to reach their health and happiness potential.


To keep up to date with what Kasey's up to on socail media and what she's writing about, check out the links below:






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(1) Campbell-McBride, N. Gut and Psychology Syndrome. UK: Medinform Publishing; 2004

(2) Campbell-McBride, N. Gut and Psychology Syndrome. UK: Medinform Publishing; 2004


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