Genes Aid Anti-cancer Effects of Veggies

NEW YORK (Reuters Health) - New research confirms that eating cruciferous vegetables, such as cabbage, broccoli and sprouts, protects against the development of lung cancer, and also hints that a person's genetic makeup may influence these anti-cancer benefits.

In a study comparing more than 2100 adults with lung cancer and an equal number without, researchers found that the protective effects of cruciferous vegetable consumption was most apparent in those who had inactive forms of two genes, GSTM1 and GSTT1.

In the study, information on vegetable consumption was obtained by a food questionnaire and the genetic status of the subjects was determined by a blood sample.

Dr. Paul Brennan from the International Agency for Research on Cancer in Lyon, France, and colleagues report in The Lancet medical journal this week that weekly consumption of cruciferous vegetables reduced the risk of developing lung cancer by 33 percent in people who had an inactive form of the GSTM1 gene.

Those with an inactive form of GSTT1 had a 37 percent protection from eating cruciferous veggies, while those with both genes inactivated enjoyed a 72 percent protective effect.

No protective effect was found in people with active forms of these two genes.

Cruciferous vegetables are rich in isothiocyanates, which are believed to be the compounds responsible for warding off cancer. Isothiocyanates are eliminated in the body by an enzyme called GST, which is produced by GSTM1 and GSTT1. Therefore, people who have inactive forms of these genes have higher concentrations of isothiocyanates.

By looking at a genetic marker for isothiocyanates," Brennan added in comments to Reuters Health, "this results in a more specific analysis of the effect of cruciferous vegetables, and provides stronger evidence than previously obtained."

The main message against lung cancer, Brennan commented, is "if you smoke, then quit, and if you do not smoke then don't start." Over and above that, he concluded, "this study provides increasing evidence that there is a specific protective effect for regular consumption of cruciferous vegetables against lung cancer."

SOURCE: The Lancet, October 29, 2005.