Effects of a soy milk supplement on plasma cholesterol levels and oxidative DNA damage in men–a pilot study

Author: Mitchell JH, Collins AR
Publication: Eur J Nutr. 1999 Jun;38(3):143-8

There seems to be a convincing evidence that isoflavones can be effective antioxidants and can be protective against hormone dependent cancers and coronary heart disease. The Asian diets are specific high in soy isoflavones and may explain why occurrence of breast and prostate cancers are rather low in Asian countries. The aim of this study was to determine the effects of isoflavones supplement, in the form of soy milk, on plasma LDL and HDL cholesterol levels and DNA damage in men.

For this study 10 healthy men were divided in 3 groups, based on their specific diet:
Group 1: consumed daily 1 liter of soy milk
Group 2: consumed daily 1 liter of semi-skimmed cow’s milk
Group 3: consumed daily 1 liter of rice drink (Rice Dream)

The men from group 1 (who toke soy milk) showed a significant increases in plasma genistein and daidzein concentrations and resulted in a decrease in oxidative damage to DNA bases detected using the comet assay. However, there was no significant effect of the soy milk on plasma cholesterol or triglyceride levels. It can be concluded that soy milk (containing isoflavones) can have a protective effect against oxidative DNA damage in lymphocytes.