Consumed in many traditional Asian populations for millennia, soya has only been a common part of the Western diet for around 60 years. Now, many of our supermarkets are full of soya milk alternatives, soya burgers and other soya-based meat replacements – not to mention traditional soya-based products like tofu, tempeh, soya milk, miso and soya sauce.
In the meantime, soya has been linked to cut the risk of heart disease compared to other diets. As a good source of protein, unsaturated fatty acids, B vitamins, fibre, iron, calcium and zinc, it is becoming increasingly popular in the West as a healthy alternative for meat. But despite more people associating soya with health over the last decade, one fear has come in front: the idea that soya can disrupt our hormones.
The controversy around soya comes down to its uniquely high content of isoflavones. These compounds have oestrogenic properties, which means they act like oestrogen, the primary female sex hormone, and bind to oestrogen receptors in the body – and oestrogen can speed up the growth of some types of breast cancer. But while scientists have extensively researched the compound’s effects in the body over the last few decades, the answer about whether isoflavones themselves can add to cancer risk isn’t straightforward.
And often, it seems soya protects against cancer risk – rather than making it worse. But exactly why that is isn’t certain.