Dietary n-3 polyunsaturated fatty acids and smoking-related chronic obstructive pulmonary disease

Frequent consumption of the n-3 polyunsaturated fatty acids found in fish may help protect smokers against chronic obstructive lung disease. The Atherosclerosis Risk in Communities (ARIC) study provided a database of 8,960 former or current smokers whose respiratory symptoms and dietary habits were known. After controlling for confounding factors such as race, age and weight, subjects in the upper 25% for fish consumption were two-thirds as likely to have chronic bronchitis, one-third as likely to have emphysema, and half as likely to have lung function in the lower 5% of the group. One explanation for the protective effect is that these diseases result from inflammatory processes triggered by tobacco smoke, and these fatty acids inhibit inflammatory processes. Chronic obstructive lung disease is so rare among nonsmokers that the effect of fish consumption could not be evaluated.