Study Links Diet to Lung Cancer Prevention

Bolstering the diet with fruits, vegetables and legumes rich in plant-based estrogens tends to protect against lung cancer, researchers will report today.

Conducted by a team of cancer-prevention researchers at M.D. Anderson Cancer Center in Houston, the analysis marks one of the few studies -- and the largest -- to examine dietary effects on lung tumor development. Lung cancer is the most common cause of cancer-related deaths in the United States.

Plant-based estrogens, or phytoestrogens, come in three main classes: isoflavones, lignans and cumestrans, with isoflavones and lignans the most widely seen in nature. All act as weak estrogens with varying capacities to influence the life and death of cells.

Isoflavones, the most common, are found in a range of foods, especially soybeans, chickpeas, yams and red clover. Lignan sources include spinach, broccoli, tea, carrots and rye grains. Cumestrans are found in beans, peas, spinach and sprouts.

“Basically, we found that people with lung cancer were less likely to consume these foods,” said Matthew Schabath, a postdoctoral fellow specializing in cancer prevention.

“What we saw was quite interesting in terms of protective effects in ‘never smokers’ and former smokers,” Schabath added. But for reasons that could not be easily explained, benefits were not apparent in smokers, according to the findings, reported in today’s issue of the Journal of the American Medical Assn.

Schabath and colleagues studied 1,674 lung cancer patients and 1,735 people without the disease from July 1995 to October 2003. Participants answered questionnaires on what they ate.

“Phytoestrogens have a variety of protective effects that have been shown in experimental models [lab animals] and lab models [petri dishes] to have various chemo-effects,” Schabath said.

Some of those effects have been as antioxidants, which means they can inhibit the prevalence of rogue oxygen molecules called free radicals.