Smokers who aren’t ready to kick the habit can help lower their risk of developing lung cancer by loading up on strawberries, apples and green tea. Researchers at UCLA’s Jonsson Comprehensive Cancer Center found that smokers who ingested high levels of flavonoids had a lower risk of developing lung cancer. These findings have far-reaching implications, as lung cancer is the leading cancer killer in both men and women in the United States, and some 90% of lung-cancer cases are caused by smoking, according to the American Lung Association.
For the study, researchers looked at 558 people with lung cancer and 837 people who did not have lung cancer, and analyzed their dietary history. Study participants who ate foods containing certain flavonoids—water-soluble plant pigments that have antioxidant and anti-inflammatory properties—seemed to be protected from developing lung cancer. Flavonoids that appeared to be the most protective included catechin, found in strawberries and green and black teas, kaempferol, found in Brussels sprouts and apples, and quercetin, found in beans, onions and apples.
According to Dr. Zuo-Feng Zhang, one of the researchers and a professor of public health and epidemiology at UCLA, flavonoids protect against lung cancer by blocking angiogenesis, the growth of new blood vessels that allows tumors to grow and spread. Flavonoids also stop cancer cells from growing, allowing for naturally programmed cell death, or apoptosis, to occur.
The antioxidant properties found in the flavonoids also may work to counteract the DNA damaging effects of tobacco smoking, Zhang said, explaining why they affected the development of lung cancer in smokers but not in nonsmokers.
According to Zhang, future research will include laboratory-based studies of flavonoids on cell lines and animal models to determine how they are protecting smokers from developing lung cancer. And, in addition to larger studies to confirm these findings, other studies are required to see if the protective effects of flavonoids extend to other smoking-related cancers, such as bladder, head and neck and kidney cancers.
Zhang and his team also plan to study which types of fruits and vegetables have the highest levels of the flavonoids found to be helpful in this study and what the optimal number of servings per day might be to provide the greatest protection.
