Why soya may not be such a super food after all

Risk: Soya is found in many guises, including tofu

It was hailed as a superfood that could fight breast cancer, strengthen bones and ease the menopause. Once thought of as exotic, today soya can be found in a variety of guises on supermarket shelves, from dairy-free milk and yogurt to vegan cheese and tofu.

Soya was first cultivated in China, where it was used as medicine and in cooking. Last year, more than one million tons of it were imported to the UK. However, there is mounting evidence that soya could, in fact, pose a serious health risk.

Experts claim soya foods might lower testosterone levels in men, hamper thyroid function, cause weight gain and disrupt hormones.

Hailing from the same family as beans, peas and lentils, soybeans are crushed to form soybean meal, which is then used to make edible soya products.

It contains all the essential amino acids to build protein in our bodies, and many vegetarians opt for soy products as a way of upping their daily protein intake.

Surprisingly, according to food-industry estimates, it is also found in 60 per cent of processed foods, adding bulk, flavour and texture.

Breakfast cereals, cereal bars and biscuits, cheese, cakes, dairy desserts, gravies, noodles, pastries, soups, sausage casings, sauces and sandwich spreads, to name just a few, often contain soya.

It appears on food labels as 'soya flour', 'hydrolysed vegetable protein', 'soy protein isolate', 'protein concentrate', 'textured vegetable protein', 'vegetable oil', 'plant sterols', or the emulsifier 'lecithin'.

Millions believe it to be a healthy option, providing protein with no saturated fat and without the risk of raising cholesterol levels. Yet it seems the very properties that made soya so attractive could also make it a health threat.

The soya plant boasts high levels of phytoestrogens that mimic the action of the body's own oestrogen. And 100g of tofu contains 12.9mg of phytoestrogens, while 100g of soya yogurt or soya milk contains 11.8mg.

Dr Margaret Ritchie, an expert in phytoestrogens at the University of St Andrews, explains: 'These oestrogen-like chemicals are up to 20,000 times weaker than natural oestrogen. If a woman is low in oestrogen, as in the menopause, the extra oestrogen absorbed when soya is eaten can help relieve menopausal symptoms.'

It may also reduce the impact of the body's own oestrogen on breast and womb tissue, protecting against breast and uterine cancers, which are triggered by the hormone.

However, according to recent studies published in the Journal Of Nutrition, soya baby formula could cause problems in male infants.

Research at Edinburgh University into the effects of soya milk on young male monkeys found it interfered with testosterone levels, prompting concerns over fertility and disease in grown men.

Furthermore, studies in Japan suggest a high intake of soy-based products can disrupt the thyroid gland, leading to weight gain, fatigue and mood problems.

Marilyn Glenville, nutritionist and author of the Nutritional Health Handbook For Women, says: 'Soya can block the uptake of the chemical iodine which is needed for a healthy thyroid. Turnips, cabbage, peanuts and pine nuts have similar effects. If you are diagnosed with a thyroid problem, you'll be told to restrict your intake of all these foods.'

She adds: 'The soya in soy burgers and sausages and added as flavour enhancers is highly processed. The soya-bean fibre is removed and the residue is soaked in an aluminium tank, then treated with chemicals such as nitrates, which some studies have linked to cancer.'

Glenville recommends reducing overall intake of processed foods and increasing intake of wholefoods.

The British Nutrition Foundation recommends adding traditional soya-bean products such as tofu, tamari, miso and tempeh to a healthy and varied diet.

'Don't overdo it,' warns Glenville. 'It is healthy in small quantities, but could be unhealthy if eaten in excess.' One small portion, about 30g, a day is ideal.

And as there is evidence linking GM soya to a raised allergy risk, ensure any soya products you buy are organic and therefore GM free.

taken from : China Daily