Q: What about protein?

A: Soya beans and soya products have had a very mixed press, being praised by some as a superfood and condemned by others as a poison.

Soya foods are a traditional part of the Japanese diet and the Japanese show better health and longevity than most Western countries. This provides good assurance of the safety of soya foods consumed in the quantities and forms common in Japan. The Japanese consume about 10 g of soya bean protein per day, mostly as tofu, roasted beans, soya milk and fermented bean products such as natto and miso. 10 g of soya protein per day translates to about 100g of tofu or half a pint of soya milk. This is more than most vegans consume so vegan soya use can be presumed healthy on the basis of the Japanese experience.

The use of TVP and fake meats is a recent Western innovation and therefore does not carry the same assurance of safety, but there is no direct evidence to suggest that such foods are not safe. The use of soya formulas for infants is clearly inferior to breast-feeding, but evidence from the USA based on decades of use of soya infant formula indicates no adverse effects compared with cow's milk formula.

There is moderate evidence that soya can reduce menopausal symptoms and bone loss and good evidence that large amounts of soya protein reduce cholesterol levels. Certain other claimed benefits, such as reduced breast cancer risk, are more dubious.

Overall, there is no reason to avoid moderate use of soya which has been a useful part of Japanese and Chinese diets for millennia and provides a useful source of protein and other nutrients.