Compound in Fruits, Vegetables May Reduce Lung Cancer Risk

Findings from a new study suggest that a compound commonly found in fruits and vegetables, such as oranges and red peppers, may reduce the risk of lung cancer caused by smoking.

Pigment beta-cryptoxanthin (BCX) was observed to reduce the amount of receptors needed for nicotine to drive lung cancer growth. The authors believe that eating fruits and vegetables high in this pigment can reduce the risk of smoking-induced lung cancer, according to the study, which was published by Cancer Prevention Research.

Each year, more than 222,500 new cases of lung cancer will be diagnosed, with more than 155,500 related deaths. The American Lung Association reported that men who smoke are 23 times more likely to develop lung cancer compared with non-smoking men, and women who smoke are 13 times more likely to develop lung cancer compared with non-smoking women.

Many of the 7000 compounds in tobacco smoke are carcinogens that damage the lining of the lungs. Although nicotine is not the direct cause of cancer, previous studies have shown that it drives tumor growth.

When inhaled, nicotine binds to nicotinic acetylcholine receptor α7 (α7-nAChR) receptors, which promote cell proliferation and the formation of new blood vessels needed for cancer growth, according to the study. Additionally, nicotine fuels the creation of α7-nAChR, which increases signaling strength and further encourages the growth of lung cancer cells.

These new findings suggest that BCX may effectively reduce α7-nAChR on the surface of the lungs, which may lead to decreased cancer cell growth.

BXC is a carotenoid that causes numerous fruits and vegetables to have a yellow, orange, or red color. Oranges, tangerines, butternut squash, and red peppers all have the compound.

The researchers previously determined that BXC consumption lowered the risk of developing lung cancer. In the new study, they aimed to find the underlying mechanisms of this relationship.

In mice models, a daily dose of BCX reduced lung cancer growth 52% to 63%, compared with mice who did not receive the compound, according to the study.

The most effective dose was 870 micrograms of BCX, which is equivalent to human consumption of 1 red pepper or 2 tangerines.

Then, the researchers examined the effects of BCX on human lung cancer cells with or without α7-nAChR. Lung cancer cells with α7-nAChR were less likely to spread upon exposure to BCX, compared with lung cancer cells without the receptor, according to the study.

Although more research is needed to better understand how the carotenoid can impact lung cancer development in humans, the authors suggest that those exposed to tobacco smoke may benefit from consuming foods with BCX.

"For smokers, tobacco product users, or individuals at higher risk for tobacco smoke exposure, our results provide experimental evidence that eating foods high in BCX may have a beneficial effect on lung cancer risk, as suggested by previous epidemiological studies,” concluded study co-author Xiang-Dong Wang, MD, PhD.