Soya supplements promote men's health
lower the risk of prostate disease and atherosclerosis in healthy
UK researchers report that a diet supplemented with soya could lower the risk of prostate disease and atherosclerosis in healthy men.
Researchers from the University Hospital of Wales in Cardiff and the Royal Victoria Hospital, Belfast examined the effects of soya, consumed through food made with soya flour, on blood levels of sex steroids, lipids and markers of oxidative stress in a small number of men.
They write: "We have shown that soya supplements reduce serum testosterone and improve markers of oxidative stress. These findings provide a putative mechanism by which soya supplements could protect against prostatic disease and atherosclerosis."
In the study at the University Hospital of Wales, the team carried out a randomised, placebo-controlled trial on 20 healthy volunteers, aged on average 36 years old.
The participants ate three scones every day in addition to their normal diet for a period of six weeks. The scones were made with either wheat or soya flour (containing 120 mg/day of isoflavones). Blood was analysed for sex steroids (including testosterone, dihydro-testosterone, oestradiol, oestrone, sex hormone binding globulin, albumin and the concentration of non-protein bound sex steroids were calculated), lipid profile (total cholesterol, high density lipoprotein cholesterol and triglycerides) and measures of oxidative stress (hydroperoxides, susceptibility of LDL to oxidation with copper and myeloperoxidase).
Results, published in January's European Journal of Clinical Nutrition, show that levels of testosterone fell in volunteers taking the soya scones. No significant changes were seen in the concentrations of the other serum sex steroids throughout the study, but significant improvements in two of the three markers of oxidative stress were seen in volunteers taking soya scones. There were no changes seen in serum triglycerides or cholesterol.
The authors warn that further dietary studies with clinical end points are needed to confirm the findings.