Chemicals found in broccoli, cabbage, bok choy, and other cruciferous vegetables may protect against lung cancer, according to a new study conducted jointly with US and Chinese researchers.

• Researchers studied more than 18,000 men.

• They recorded 259 cases of lung cancer during the study's follow-up period.

• They found that the men with detectable amounts of chemicals known as isothiocyanates in their bodies had a 36% lower chance of developing lung cancer over 10 years.

• Researchers from the National Institute of Environmental Health Sciences (NIEHS) in North Carolina along with colleagues in China performed the study in four small communities in Shanghai.

Isothiocyanates are found in broccoli and other so called "cruciferous" vegetables.

The study is the first to link levels of isothiocyanates with a decrease in cancer risk, as previous studies had relied on dietary questionnaires that give no information on absorption or blood levels.

Though the chemicals did lower cancer risk by 36% in this study, smoking alone increases lung cancer risk by as much as 10 times.

The researchers think that isothiocyanates fight cancer by promoting the production of antioxidants and by inhibiting enzymes that allow carcinogens in cigarette smoke to damage DNA.

Isothiocyanates are not commercially available in pill form, and being that there are more than 20 different isothiocyanates, it is doubtful that a supplement would be able to duplicate the proper mix of these chemicals to get the same benefit.

According to one of the researchers, it is more prudent to "just eat the vegetables", rather than looking for benefits from supplements.

The Lancet August 26th 2000;356:724-729

Dr. Mercola's Comments:

While we should not seek a magic bullet for smoking it is good to know that the cruciferous vegetables will reduce the risk of cancer in smokers, and most likely non-smokers as well. The likely reason why this study showed improvement and earlier studies looking at beta carotene did not is likely related to the fact that this study used the actual whole food product while the beta carotene used synthetic supplements. Nearly every time the whole food products will be superior to the processed supplement, especially if it is synthetic. Related Articles: Vegetables May Lower Stroke Risk Vegetables Lower Prostate Cancer Risk Eating Vegetables May Cut Diabetes Risk