Is soya safe?

Is soya safe?

Soya and soya products have been consumed for many years, particularly in Asia, and there has been much talk over their health benefits (that’s another blog!). Soya has made many food headlines over the past decade, however, concern about soya possible links with oestrogen sensitive breast cancer, have raised the question – is soya safe?



Is Soya safe?

Is Soya safe?

Soya has a high natural phytoestrogen (the isoflavones; genistein, daidzein and glycitein) content. These phytoestrogens have a similar chemical structure to oestrogen, competing for and weakly binding to certain oestrogen binding sites in the body.

The proposed link between oestrogen sensitive cancers and soya is a logical one! Could soya’s high phytoestrogen content compete for the oestrogen binding sites in body and increase the growth of oestrogen sensitive cancer cells? This was demonstrated in rats and mice and raised much of the concern and publicity around soya’s safety, however, it was later shown that rodents metabolize phytoestrogens differently to humans.

Is soya safe? – Binding sites

Soya phytoestrogens have been found to bind to different oestrogen receptor sites compared to the hormone oestrogen. This subtle difference in the oestrogen receptors that phytoestogens bind to, and their location in our body, has an important effect on the activation of specific oestrogen receptor sites. Subsequently, this specific receptor activation influences the proliferation and inhibition of  breast cancer cells. This important difference in the specific receptors that phytoestrogens activates, plays an important role in answering the question, is soya safe?

Is Soya safe?

Is Soya safe?

Does soya increase the incidence of breast cancer in women?

There have been 7 recent observational  studies (studies that follow patients up to identify an increased risk) investigating the relationship between soya intake and breast cancer recurrence in women who have previously had breast cancer. These studies looked at over 13,000 patients with a 3-7 years follow up period. None of the studies demonstrated an increased risk of recurrence, some even found a reduced risk.  So, although the research has its limitations, it’s looking good for the soya bean!

Is soya safe? – What about processed soya products?

There is little evidence to demonstrate a risk between processed soya products, however,  from a nutritional perspective, processing generally removes some of the good stuff and adds more of the bad (mainly sugar and salt). Reading the labels is important and where possible opt for less processed soya products, such as tofu, whole bean soya milk, dried soya mince or unprocessed soya, such as whole soya beans or edamame beans. Whole soya beans can now be purchased in many supermarkets frozen, making a quick, easy and tasty addition to a stir fry.

Is soya safe? – The Internet Dietitian’s conclusion!

The evidence to date concludes that soya foods are safe for women concerned about, or who have developed breast cancer. Those women can continue to include and enjoy Soya foods as part of a healthy balanced diet. But, it’s not just about soya! A third of cancers diagnosed in the UK each year are linked to smoking, diet, alcohol and obesity. Look at the bigger picture in the pursuit of health,  as lifestyle changes can play a key role in preventing breast and other forms of cancer. Please contact Sian at The Internet for more information.


If you have enjoyed reading this  ‘Is soya safe?’ blog, you may be interested in reading ‘Health benefits of soya’ – coming soon!


photo by: williami5
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Registered Dietitian and owner of The Internet Passionate about family nutrition and the dietary treatment of Irritable Bowel Syndrome (IBS) Busy mum of 3 little uns. Cheshire, UK

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Leave A Reply (4 comments so far)

  1. 大樂透獎金
    3 years ago

    Amazing website, thank You !!

  2. aditi
    2 years ago

    hii great post!! i like it!
    Adisoy has made soy buttermilk, Soy milk Milsoy in five different flavours and also plain and spiced Tofu to provide you with all soybean benefits. Soy can protect against various types of cancer and improve cardiovascular health available at

  3. Brian Sladovich
    7 months ago

    Reminds me of Marathon Man – Is it safe? – Seriously though, I’m a male vegetarian and use a lot of soya products in my diet; soya milk, mince etc. I’m a little concerned about the high phytoestrogen levels and also that much of the soya comes from GM crops. I will continue to use it but, try to substitute it with ‘Quorn’ products and so called almond milk. Note that Alpro & Almond Breeze have only about 2.5% almond content in its almond (milk) drink. The rest is made up with undisclosed ‘plan’ products. The only dairy I will consume is a little cheese and fat-free Greek style yogurt. It’s a minefield!

    • Sian Riley
      7 months ago

      Your approach of striving for variety with your vegetarian protein sources is a good one – after all variety is the spice of life! However the research I’ve done for this blog reassured myself that soya phytoestrogens bind to different receptor sites compared to the hormone estrogen and therefore have shown their safety in adult males in the concentrations that you are consuming them in.

      As you’ve noted the almond content in milk is pretty low, leading to a lower protein content compared to soya and cow’s milk. Try swapping your ‘greek style’ yoghurt for greek yoghurt if you want to increase your protein intake.

      GMO aren’t grown commercially in the UK. Most of the leading brands and supermarkets in the UK ensure their ingredients are GM free too. Check the label or the supermarkets website for non GM ‘Danube Soy Association’ ‘Proterra foundation’ & RTRS marks.

      Hope this helps?

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