The National Lung Association has dubbed May "Breathe Easy Month." As the month comes to a close, we wanted to recognize this aspect of May with a review of some ways to improve your lung function through healthful eating. While the National Institute of Cancer maintains that giving up smoking is the most beneficial health action that smokers can take to lower their risk of lung cancer, the following dietary recommendations may also offer protection against lung cancer -- for smokers and nonsmokers alike.

1. Eat carotenoid-rich foods.

Carrots, green and red bell peppers, sweet potatoes, winter squash, and leafy greens contain DNA-friendly antioxidants that protect the lungs. Beta carotene, a vitamin A precursor, has been the carotenoid most associated with lung cancer protection. Mangoes, apricots, cantaloupes, and peaches are excellent fruit choices. Skip the pills and get beta-carotene from food sources instead. A 1994 Finnish study showed an increased rate of lung cancer among smokers given high doses of beta-carotene supplements. Other studies have shown that increased beta carotene from food decreases cancer rates. Lycopene, another carotenoid, has also been found to protect against lung cancer. The antioxidant action of lycopene also helps ward off prostate cancer. Tomatoes, tomato products, guava, watermelon, and pink grapefruit are all good sources of lycopene.

2. Eat one serving of cruciferous vegetables daily.

Cruciferous vegetables (like broccoli, cabbage, kale, watercress, and Brussels sprouts) contain a phytochemical called isothiocyanate. Isothiocyanate blocks an enzyme that activates cancer-causing agents in tobacco smoke. Get at least one serving of these helpful veggies every day.

3. Find food sources of selenium.

A study indicated that dietary selenium supplements (200 mcg) might significantly lower the incidence of lung cancer. Since the possible benefit of selenium supplementation needs to be assessed in a larger population study, eat heart-healthy food sources high in selenium. These include Brazil nuts, whole grains, and tuna.

4. Eat foods high in vitamin E.

Vitamin-E-rich foods include nuts (almonds, walnuts, & sunflower seeds), avocados, mangoes, and wheat germ. Vitamin E (tocopherol), an antioxidant, maintains lung cell integrity. A Finnish study showed that a diet rich in Vitamin E lowered the risk of lung cancer among smokers by 20%.

5. Limit fat intake.

Limit fat intake, especially saturated fat in red meat and high-fat dairy foods. Studies show a direct correlation between lung cancer and the intake of animal fats. Eat more fatty fish since these are high in omega-3 fatty acids (good fats) instead of saturated (bad) fat. Try salmon, mackerel, or tuna. Beans as healthy high-protein alternatives.

6. Get enough vitamin C.

Oranges contain vitamin C and folic acid (a B-complex vitamin). Both nutrients appear beneficial in protecting against lung cancer. Other high Vitamin C foods include kiwi, potatoes, and red bell peppers. Asparagus, broccoli, and dried beans are good sources of folic acid.

7. Get fit!

Two recent studies show evidence that regular exercise may exert an "anti-cancer" effect. In addition, one of the studies found that men who were fitter had a lower risk of dying of lung cancer. The researchers suggest that fitness may protect the lungs against the ravages of tobacco smoke and that being sedentary may contribute to lung cancer. The American Cancer Society recommends 30 minutes of cumulative moderate physical activity on most days of the week.

The bottom line:

While research continues to determine diet's role in lung cancer, the best advice for smokers who want to reduce their cancer risk is to stop smoking. For nonsmokers who wish to prevent lung cancer, a low-fat diet with 5-9 servings daily of colorful fruits/vegetables and grains is a good bet.

By Sandy Hernandez, MS, RD.