Nutrition and respiratory health in adults: findings from the health survey for Scotland.

There is a growing body of evidence to support the hypothesised links between consumption of antioxidant rich foods and the occurrence of obstructive airway disease. The main research question was to examine the relationships between two types of dietary exposure and two indicators of respiratory morbidity in Scottish adults. The relationships between dietary consumption of fruit, vegetables and fish, and plasma levels of vitamins A, C, E and beta-carotene, and pulmonary function (forced expiratory volume in one second (FEV1)) and symptoms (phlegm production and shortness of breath with wheezing), were examined in a random population sample of adults. A dose/response relationship was found between fruit consumption and pulmonary function. In comparison with eating fruit rarely or never, eating fruit at least once per day, 1-6 times per week, and 1-3 times per month were associated with differences of 132, 100 and 63 mL in FEV1, after adjustment for known confounders and dietary intake of vegetables and fish (n=6186). An SD score change in plasma vitamin C was associated with a 49 mL difference in FEV1 (n=930). Fruit and vitamin E were associated with a reduced prevalence of phlegm production for 3 months or more per year. The most beneficial combination of dietary components may be found in natural foodstuffs, particularly fresh fruit.