Healthful Eating for Better Lung Function

Diet May Keep Chronic Lung Disorders at Bay

You don't smoke, and you avoid second hand smoke and air pollution as much as possible. Are there other steps you can take to help maintain healthy airways and lung function? Well, research suggests that your diet can influence the risk of chronic bronchitis and asthma, and may lessen symptoms for those who already suffer from such conditions.

Mediterranean-Style Diet Fends Off COPD

Consuming a "Med"-style diet rich in fruits, veggies and fish may halve the risk of chronic obstructive pulmonary disease (COPD), the umbrella term for chronic bronchitis and emphysema (1).

Harvard researchers tracked more than 42,000 male health professionals for 12 years, ranking them by how closely they followed a Med style diet or how much they stuck to a Western dietary pattern. After adjusting for age, smoking and other factors, greater adherence to the Med diet was associated with a 50% decrease in COPD risk compared to men with the lowest adherence. At the same time, men who followed a Western style diet most closely were about four and a half times more likely to suffer from newly diagnosed COPD as those who ate the least from that menu.

The Western diet was defined as one high in processed foods, refined grains, cured and red meats, French fries and deserts. The researchers noted that this diet contains nitrites used to preserve or color foods such as bacon, corned beef, luncheon meats, sausage and ham. Nitrites generate free radical compounds that could contribute to progressive deterioration of pulmonary function. A high-glycemic diet like the Western eating pattern has also been linked to impaired lung function.

In contrast, a Med-style diet is rich in beta-carotene, vitamins C and E, polyphenols (bioflavonoids), omega-3s, and essential minerals. It is these antioxidants and polyphenols that appear to offer protection. According to the study authors, their findings are consistent with previous study results suggesting a beneficial effect for antioxidants on COPD - particularly vitamin C and, to a lesser extent, vitamin E.

Fish & Whole-Grains Guard Against Asthma

A study published late last year also supports components of the Med-style diet as helpful for young asthmatics (2). With the assistance of their parents, Dutch public health researchers assessed the diets of nearly 600 children 8-13 years old.

The investigators found that whole grains and fish intake were most closely linked with asthma risk. High intakes of whole grains and fish were associated with a 54% and 66% reduction in the odds of having asthma, respectively. Kids who consumed a high intake of both foods experienced significantly less wheezing. Only 4.2% of children who ate the most grains and fish suffered wheezing, while 20% of those eating the least exhibited this symptom.

It's also worth noting that a diet rich in antioxidants found in fruits and veggies is important for expectant moms. A study conducted by Harvard researchers found that higher maternal intakes of antioxidants during pregnancy decrease the risk for wheezing illnesses in early childhood (3).

Fish Oil Helps Exercisers with Asthma

Exercise is a powerful trigger of asthma symptoms in about 80% of asthmatics. Vigorous exercise can cause airways to narrow, resulting in shortness of breath, wheezing and chest tightness. Recently, researchers from Indiana University tested the ability of fish oil to reduce the severity of these symptoms (4). They found that when asthmatics were given high dose fish oil supplements instead of placebos, they had better pulmonary function and needed to use a bronchodilator less frequently after a bout of exercise.

References

1. Varraso R, et al. Prospective study of dietary patterns and chronic obstructive pulmonary disease among US men. Thorax (Br Med J) E pub online, May 15, 2007.
2. Tabak C, et al. Diet and asthma in Dutch school children (ISAAC-2). Thorax (Br Med J) 61:1048-53, 2006.
3. Litonjua AA, et al. Maternal antioxidant intake in pregnancy and wheezing illnesses in children at 2 y of age. Am J Clin Nutr 84:903-11, 2006.
4. Mickleborough TD, et al. Protective effect of fish oil supplementation on exercise-induced bronco-constriction in asthma. Chest 129:39-49, 2006.