FOOD FOR THOUGHT

Stocking the fridge for a vegan month? Dietitian Laura Tilt digs deeper than the headlines to reveal the truth behind soya scare stories

Is soya really safe to consume?

FFS. Tofu? How can tofu be bad for you? I get it. Just when you think you’ve knocked the dairy debate on its head, scary soya claims make you want to throw out the contents of your freshly stocked fridge. Sales of soya have soared in recent years as more of you swap semi-skimmed for soya in your flat whites and because, well, edamame. But it’s often suffered a bad press, with studies linking female consumption of soya to breast cancer and even infertility. So where do these fears stem from? Most are linked to the naturally occurring phytoestrogens (hormonelike plant compounds) in soya, known as isoflavones. Phytoestrogens mimic the effects of oestrogen in the body, leading to concerns that soya may be harmful due to a link between high oestrogen levels and health risks, including breast cancer – oestrogen increases cell division and may therefore contribute to the growth of cancerous cells. But the plot thickens. In a 2008 study published in the British Journal Of Cancer, researchers found breast cancer risk was significantly reduced in women consuming high intakes of soya (providing more than 10mg isoflavones), compared with those eating smaller amounts. Quite the turnaround. This can be explained by the presence of two oestrogen receptors in the human body – alpha and beta. When it comes to breast cancer, alpha poses the biggest risk. According to experts, isoflavones preferentially bind to the beta-receptor, which may actually have a protective effect. More recent research concluded that for women living with breast cancer, soya intake isn’t detrimental for prognosis or survival. Cancer risk aside, a quick google of ‘soya’ and ‘fertility’ is enough to make you ditch those dairy-free milkshakes for good. It comes down to the link between genistein (the primary isoflavone in soya) and reduced fertility in studies done on sheep, mice and rats. But these studies typically involved consuming genistein at levels five times higher than the levels you’re exposed to by eating food containing soya, so there’s an element of scaremongering here. In fact, more recent research suggests soya might actually be good for fertility. In a 2015 study of women undergoing fertility treatment, isoflavone intake was positively linked with live birth rates. And, according to a 2016 study, soya isoflavones may even protect against the negative effects of BPA (the chemical found in plastic and cans) on fertility. The upshot is there just isn’t enough convincing evidence in human trials to suggest you need to ditch soya. When it comes to fertility, there are arguably more impactful things to consider; carrying too much or too little body fat, smoking, alcohol and high stress levels can all negatively affect your chances of conception. And aside from isoflavones, eating soya protein as part of a healthy diet has been linked with a lower risk of heart disease, which is another reason not to ditch it. Edamame me up.