Broccoli May Protect Some Against Lung Cancer

Compound in Cruciferous Vegetables Could Reduce Risk

From the WebMD Archives

Oct. 27, 2005 -- People genetically at risk for lung cancer may benefit from crunching on some cruciferous vegetables.

A new study shows people with a certain genetic mutation who ate the most broccoli, cabbage, and brussels sprouts were about a third less likely to develop the deadly disease.

Researchers say the protective effect is likely due to compounds called isothiocyanates, which are found in large amounts in vegetables from the cabbage family, including broccoli, cabbage, and brussels sprouts.

Previous studies in animals have suggested that isothiocyanates may protect against lung cancer, but several smaller studies of cruciferous vegetables in humans have failed to show any definitive anticancer effects.

Can Cabbage Quash Lung Cancer?

To determine if any particular subgroups of people might benefit from eating vegetables rich in isothiocyanates more than others, researchers compared the effects of cruciferous vegetable consumption in people with genes that eliminate isothiocyanates from the body.

People with inactive forms of the genes GSTM1 and GSTT1 retain higher levels of isothiocyanates than those with active forms of the genes because their bodies don't get rid of them as quickly.

In the study, researchers compared how much broccoli, cabbage, and brussels sprouts were eaten on a weekly basis by more than 4,000 people in central and Eastern Europe. About half of the participants had lung cancer and half did not.

The results showed that consumption of cruciferous vegetables was associated with a 33%-37% reduction in lung cancer risk among people with an inactive form of one of the two genes. Among those with an inactive form of both genes, the reduction in risk provided by eating cruciferous vegetables was doubled to more than 70%.

Similarly protective effects were found for cabbage and a combination of broccoli and brussels sprouts.

No reduction in lung cancer risk was found among people with the active forms of either gene.

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SOURCES: Brennan, P. The Lancet, Oct. 29, 2005; vol 366: pp 1558-1560. News release, The Lancet.
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