• Australia’s soy consumption has increased 50 per cent. (Flickr)Source: Flickr
Australians love our soy-based foods, from soy milk to tofu, fermented soybeans and soy sauce. But as our consumption of the plant-based product grows, so too do the online claims that soy is not the wonder food we once thought. Could soy do more harm than good?
Yasmin Noone

11 Jan 2016 - 2:04 PM  UPDATED 12 Jan 2016 - 11:05 AM

Soy: vegans love it, vegetarians embrace it and health conscious folk around Australia celebrate it as a holy alternative to meat and dairy.

Australia’s soy consumption increased 50 per cent in the decade prior to 2009, according to a Tetrapak report. But are soy-based products really the healthier option?

Consultant dietician-nutritionist for the Dietitians Association of Australia, Dr Kellie Bilinski, says mostly yes: soy is low in sodium and high in protein.

“That makes it a healthy food option for vegans and vegetarians wanting protein, calcium and iron,” she says.

However, soy is not for everyone. Various bodies of research have raised doubts about how far soy’s health benefits actually reach.

So here are facts about soy: the claims, the research and the inconclusive evidence.


Breast cancer prevention?

Some research suggests that phytoestrogens (or isoflavones) found in soy may mimic the hormone oestrogen when consumed and provide a preventative buffer against breast cancer.

“If you look at the research in Asian cultures, soy aids in protection against breast cancer,” says Dr Bilinksi. “They have lower rates of breast cancer and that could be due to soy consumption.”

However, the Cancer Council Australia concludes, there is no association between soy foods and cancer risk reduction.


Breast cancer cure? 

The Cancer Council advises that this is wrong: soy capsules and products can’t treat breast cancer. In fact, it might promote tumour recurrence and stimulate existing tumour growth in breast cancer survivors.


Menopausal symptom remedy? 

Short-term studies show that soy does not significantly improve hot flushes or other menopausal symptoms.


Lowering cholesterol?

Despite popular belief, studies show that soy doesn’t make a difference in mild cholesterol cases but it does slightly help people with very high levels of LDL cholesterol.


Allergic reactions?

Allergy and Anaphylaxis Australia say around 2–3 per cent of all young children are allergic to soy and must avoid food containing soy and soy derivatives, or else face disastrous health effects. 


Soy-based formula is bad for infants?

Australia’s National Health and Medical Research Council guidelines on infant feeding state that soy-based formulas “are not suitable alternatives for infants with allergies to cow’s milk-based formulas”. 

Activists tagging soy-based infant formula with labels identifying them as containing genetically modified ingredients.

Depress thyroid functions and cause goitres in healthy children and adults?

People with thyroid issues are advised to take caution when consuming soy as it may interact with their thyroid medication.

A Medical Journal of Australia report in 2010 also warns that soy-based milk manufactured with seaweed can cause iodine toxicity in adults and infants and result in serious thyroid dysfunction. 

In 2014, the soy milk product ‘Bonsoy’ was recalled by Australian food authorities after being linked to a host of thyroid problems. It has since been reformulated to no longer include seaweed extract


Male infertility?

A study conducted by Dr Geoffry De Iuliis from the University of Newcastle, officially published in 2008, is often cited to link male infertility with soy consumption.

However, Dr De luliis told SBS Life, the link was never confirmed.

“We only tested the effects of soy on the human sperm at a very high level,” he says.

“We said there was ‘potential’ there for negative effect on male fertility.”

But, as is the case with most of the arguments for or against soy, “more research is needed”.


Want to add more soy to your diet? Click here for some tofu recipes. 

Soy milk image by mc559 (Flickr).