Comparison of the effects of adding fish high or low in n-3 fatty acids to a diet conforming to the dietary guidelines for Americans

Abstract

Objective To compare the effects of diets containing high or low amounts of n-3 fatty acids on lipid levels in men. Design A continuous 40-day feeding study was conducted using a 5-day cycle menu. The control diet, which was fed the first 21 days of the trial, contained 32% of energy as fat and 44.4 total dietary fiber per day. Total serum cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) were evaluated 1 day before the trial began and on days 21 and 41. Subjects 17 men aged 21 to 42 years who were free-living individuals with no apparent illnesses of hyperlipidemia. Intervention The treatment diets, which were substituted daily for the regular entrees for the last 19 days of the trial, contained 180 g/day of either farm-raised catfish or wild Alaskan salmon. Statistical analyses performed Serum data were analyzed using analysis of covariance with the initial values as the covariates. Results After 21 days on the control diet, TC and TGs decreased; however, there were no further decreases during the last 19 days when fish was consumed. LDL-C remained unchanged after the first 21 days but was lower than the initial value by day 41. HDL-C levels were similar over the 40 days. There were no significant differences in lipid levels of men who consumed catfish and those who consumed salmon. Applications/conclusions Farm-raised catfish compared favorably to wild Alaskan salmon when incorporated into the total diet in regard to lipid levels in men.