Eating one or more servings of broccoli a week could reduce the risk of prostate cancer, one of the most common in Western men, and prevent tumors from becoming more aggressive.
For the first time, a research group from the Institute of Food Research led by Professor Richard Mithen has explained how broccoli could reduce the risk of cancer by conducting a study on men. Until then, the hypotheses put forward were based on experiments on animals.
During the study, two groups of men at risk of developing prostate cancer ate 400g of broccoli with a high level of glucosinolate, and the other 400g of peas per week, added to their diet. usual for a year. Cells were taken from their prostate before the start of the study, and after 6 and 12 months of diets. Gene expression was then studied with Affymétrix microarray technology.
Modulated gene expression
It was shown that gene expression had more consistent changes in men on the broccoli diet than in those on the pea diet, and that these changes may be associated with a reduced risk of developing cancer, which had been reported by epidemiological studies. It had already been proven that the 50% of the population who had the GSTM1 gene gained more from eating broccoli than those who did not, the presence of this gene having a strong effect on the change in gene expression caused by eating broccoli.
A few servings a week change everything
Previous observational studies had shown that diets high in cruciferous vegetables could reduce the risk of prostate cancer and other chronic diseases, but did not provide an explanation of how this happened. Animal experiments have provided these explanations, but these studies are usually conducted at such doses that they could not be applied to a typical human diet.
Cabbage, cauliflower, broccoli modify cell transmission
The results show that relatively small amounts of cruciferous vegetables in the diet (a few servings per week) such as broccoli, Brussels sprouts, cauliflower, cabbage, watercress, kale, radish or wasabi can have broad effects on gene expression by changing the transmission pathway of cells. These transmission paths are routes by which information is transmitted through a molecular cascade that amplifies the signal to the nucleus of the cell where gene expression takes place.
A team of Norwich researchers planned a study with men with prostate cancer to compare the effects of standard broccoli with those of the specific high-glucosinolate variety used in the previous study.
Two to three servings of crucifers per week
“Other fruits and vegetables can also reduce the risk of prostate cancer using other mechanisms,” explained Professor Mithen, “once we understand this, we can provide better dietary advice in which combinations fruits and vegetables are likely to be particularly beneficial. In the meantime, eating two or three servings of cruciferous vegetables a week, and even more if you don’t have the GSTM1 gene, should be encouraged. »