Pneumonia is a serious infection of the lower respiratory tract that can lead to death in elderly individuals. The fifth leading cause of death in the United States is pneumonia and influenza. A study just published in the American Journal of Clinical Nutrition (2005;82(3):668-674) shows that higher intakes of certain essential fatty acids and fish may reduce the incidence of infectious pneumonia. Previous research has shown that supplementation with n-3 and n-6 fatty acids can reduce the incidence and duration of infections in children, reduces inflammatory cascades and improves immune function. So, researchers theorized intake of these fatty acids may influence the risk of catching pneumonia.
The dietary habits of men enrolled in a large ongoing trial, the US Health Professionals Follow-UP Study, were examined to determine if there was any association between consumption of n-3 and n-6 fatty acids and fish with the incidence of community acquired pneumonia. The results showed that men who had the highest intakes of a-linolenic acid and linoleic had a 32% and 30% reduction, respectively, in risk of pneumonia when compared to men with the lowest intake. As well, there was a slight reduction in risk with increased fish consumption. These associations stayed constant even when other potential confounding dietary habits were adjusted for statistically.
The main dietary sources of a-linolenic and linoleic acids in the study were canola and soybean oils, nuts, and oil-based salad dressings. Analysis showed that the effect of the two fatty acids could not be separated, possibly indicating other constituents in vegetable oils, the major source of linoleic and a-linolenic acids, may be the true protective factor. The authors note, "essential fatty acid intake may decrease infection risk by reducing inflammation and improving insulin sensitivity."
They also indicate their results "provide further support for recommendations to replace animal and partially hydrogenated fats with those foods and nonhydrogenated vegetable oils in general." Prior to this study, the only known modifiable risk factors were smoking, alcohol use, physical activity and weight gain. It appears now we can add dietary factors to that list.
Posted by Kristopher Foster on April 4, 2006 10:17 AM
