In the last Sourcing Science we reported that a substance in cruciferous vegetables (broccoli, brussels, sprouts and kale) called sulphurophane may be responsible for the protective role these vegetables confer against cancer. A new study published in the Lancet shows that other substances contained in cruciferous vegetables called isothiocyanates protect against lung cancer in certain people. Vegetables such as cabbage, broccoli and sprouts contain chemicals called isothiocyanates which are thought to protect against lung cancer. However, some people carry certain genes (GSTM1 and GSTT1) which produce enzymes that break down these valuable chemicals. These genes are not active in all people; 50 per cent of people carry an inactive form of GSTM1 while 20 per cent of people carry an inactive version of GSTT1 and just 10 per cent of people carry inactive versions of both genes. The researchers looked at 2,141 patients with lung cancer and 2,168 healthy individuals from Poland, Slovakia, Czech Republic, Romania, Russia and Hungary where cruciferous vegetables are a usual component of the diet. DNA samples were taken to see which versions of the genes they carried and their diets were monitored. In people who carried both active versions of the gene no protective effect of cruciferous vegetables was seen. However, in people with inactive versions of the genes these vegetables had a protective effect that ranged from 33 per cent (inactive GSTM1) to 37 per cent (inactive GSTT1) to a whopping 72 per cent (inactive GSTM1 and GSTT1). These results provide strong evidence for a substantial protective effect of cruciferous vegetables on lung cancer. Lung cancer causes more than 33,000 deaths in the UK each year and finding a simple way to protect some people against this disease would be a huge advantage. Cabbage soup anyone?
Brennan P, Hsu CC, Moullan N, Szeszenia-Dabrowska N, Lissowska J, Zaridze D, Rudnai P, Fabianova E, Mates D, Bencko V, Foretova L, Janout V, Gemignani F, Chabrier A, Hall J, Hung RJ, Boffetta P, Canzian F. 2005. Effect of cruciferous vegetables on lung cancer in patients stratified by genetic status: a mendelian randomisation approach. The Lancet. 366 (9496) 1558-1560.