Diet Rich in Antioxidants May Reduce Lung Cancer Risk in Smokers and Nonsmokers

Several dietary antioxidants, like carotenoids and vitamin C, that are found in common food sources may protect against lung cancer, even among heavy smokers, according to a new study published in the journal Frontiers in Oncology.

Researchers from Canada and the United Kingdom used data from a population-based case control study conducted in Montreal, Québec, Canada. Both men and women, aged 35 to 75 years, and living in the Montreal area were eligible to participate in the study. A total of 1,203 people were in the case group and 1,513 in the control group.

Trained interviewers conducted in-person interviews with the subject or a proxy respondent (if the subject was deceased or too ill to respond). Information was collected on a wide range of factors including subjects’ socioeconomic background, detailed occupational history, smoking history (smoking status, changes in smoking intensity levels and interruptions, cigarette-years, time since cessation) and lifetime intake of alcoholic beverages and dietary intake.

The authors on the study found that high intakes of beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene and vitamin C were associated with a reduced risk of squamous cell carcinoma, while high intakes of beta-carotene and alpha-carotene lowered the risk of adenocarcinoma. Both medium and high intakes of beta-cryptoxanthin and lycopene reduced the risk of small cell carcinoma.

Yellow and orange foods like carrots and sweet potatoes are good sources of beta-carotene and alpha-carotene. Beta-cryptoxanthin can be found in sweet red peppers, mango and peaches. Foods of red and pink color, such as tomatoes, watermelon and pink grapefruit are great sources of lycopene.

Some of these antioxidants were also associated with a lower lung cancer risk in women who were moderate smokers or nonsmokers. The study’s lead author said that this finding has not been previously reported.

This study is also the first to consider both smoking duration and time since quitting, two key smoking history factors for lung cancer.

Smoking is the leading risk factor of developing the disease. In fact, about 80 percent of lung cancer deaths are caused by smoking, and many others are caused by exposure to secondhand smoke, according to the American Cancer Society. However, several other risk factors may also contribute such as genetic mutations, exposure to radon, secondhand smoke, air pollution, exposure to asbestos, diesel exhaust or certain other chemicals.

According to 2012 statistics — the last year for which this information is available — from the Centers for Disease Control and Prevention lung cancer remains the leading cancer worldwide. It accounts for 13 percent of all cancers diagnosed, or 1.8 million people around the world.

The study’s authors concluded that diet can influence the occurrence of lung cancer. They recommend consuming a diet that is rich of fruits and vegetables high in carotenoids and vitamin C to reduce the risk of developing lung cancer in both smokers and in people who have never smoked.