Nutrition and lung health.

Several lung diseases have been associated with oxidative stress and linked to oxidant insults such as cigarette smoke, air pollutants and infections. Consequently, dietary factors and nutrients with a potential protective role in the oxidative process and inflammatory response have been implicated in the genesis or evolution of these diseases. These nutrients include fruits and vegetables, antioxidant vitamins such as vitamin C, vitamin E, betacarotene and other carotenoids, vitamin A, fatty acids and some minerals such as sodium, magnesium and selenium. This article reviews the potential mechanisms by which dietary factors may affect respiratory health, and discusses epidemiological evidence for the link between diet and lung diseases. Most of the available evidence on the effect of dietary factors on the risk for obstructive lung diseases are derived from cross-sectional studies. These studies suggest that antioxidant vitamins, particularly vitamin C, and to a lesser extent other antioxidants, have a protective effect against lung diseases. However, the few intervention studies have not been conclusive. High intake of fresh fruit and some vegetables appears to have a beneficial effect on lung health and their consumption should be recommended on a daily basis. Supplementation of vitamin C and other antioxidants could be proposed in subjects with additional oxidative stress challenge, such as exposure to high levels of air pollution. Subjects with impaired immune response could also benefit from vitamin A and zinc supplementation. Further studies are needed to determine the impact of diet on the incidence and evolution of lung diseases.