BBC News HEALTH Doubt cast on soya for menopause

February 14, 2003

http://news.bbc.co.uk/1/hi/health/1721472.stm

Doubt cast on soya for menopause

Cooking with soya could help reduce cholesterol

Many women swear by chemicals found in soya to relieve the effects of the menopause - but research has undermined evidence of some benefits. The research, published in the American Journal of Clinical Nutrition, found that there was no difference in the hormone levels of women taking the supplements compared with other women. However, there was evidence that soya could help women keep strong bones - and good cholesterol levels - after the menopause. Soya is said to work because it contains plant hormones called phyto-oestrogens - which are similar in structure to a sex hormone produced by women. When the menopause diminishes the production of female sex hormones, it is claimed the phyto-oestrogens can partially mimic them and relieve symptoms such as hot flushes and night sweats. Soya sources Proponents of soya claim they can also reduce cholesterol levels in the blood stream, perhaps extending the protection against heart disease enjoyed by pre-menopausal women. Good sources of soya include tofu, soya milk and soya flour. However, a team of researchers from the University of Illinois School of Public Health in Chicago carried out tests on 73 postmenopausal women, none of whom was taking HRT. They were given diets including either low or high doses of soy chemicals, or one containing a milk protein. Blood samples were collected at the beginning of the study and after three and six months on the diets. However, over time, there was no significant difference in the levels of several hormones between the three groups. Thyroid hormone Circulating thyroid hormones were very slightly increased in the group getting the highest dose of soy chemicals, and there were also encouraging signs in other areas. Those who took the highest dose had improved bone density - and higher concentrations of so-called "good" cholesterol. However, the researchers concluded that there was no evidence that soy intake was having any effect on levels of key sex hormones in the blood, which might bring relief from menopausal symptoms. 'More research needed' Proponents of soy have pointed to studies which suggest fewer menopausal symptoms in women from countries with a soy-rich diet, such as in Asia. A spokesman for the British Nutrition Foundation said: "Several studies have looked at the effect of phyto-oestrogens on the symptoms of the menopause. "Some have shown a beneficial effect, others have shown no effect. "Further studies are needed in this area before firm recommendations and advice can be given. In the meantime, for those experiencing menopausal symptoms, the best advice is to consult your GP to discuss the most appropriate treatment."