Influence of vegetables on the expression of GSTP1 in humans--a pilot intervention study (Sweden).

Background: There are indications that a diet rich in vegetables and/or fruit has a protective effect against several types of diseases, including cancer. Data from experimental and epidemiological studies suggest that antioxidant constituents may provide protection against environmental carcinogens.

Aims: This study investigated the effect of additional vegetables in the diet on the expression of the endogenous antioxidant enzyme GSTP1 in human lymphocytes.

Methods: Six subjects were given an addition of mixed vegetables to their normal diet for a period of three weeks. The expression of GSTP1 protein and mRNA in lymphocytes was measured by Western blot and RT competitive PCR.

Results: After the intervention all six subjects had lower levels of GSTP1 mRNA, and five of the six subjects had lower GSTP1 protein levels. This suggests that increased vegetable intake decreases GSTP1 expression, possibly through the supply of additional antioxidants.