Modulation of Fasted and Postprandial Plasma Lipids in Healthy Volunteers by a Dietary Mixture of Omega-3 Fatty Acids and Conjugated Linoleic Acid

Effects of a dietary combination of omega-3 polyunsaturated fatty acids (n-3-PUFA) and conjugated linoleic acids (CLAs) on fasting and postprandial plasma lipids was investigated in healthy volunteers with different ages and body mass index (BMI). Lean (BMI 20-26 kg/m2) and obese (BMI 29-35 kg/m2), young (20-37 years) and older (50-65 years) men consumed 3 g/day each of CLA and n-3-PUFA or 6 g/day control oil for 12 weeks in a double-blinded, placebo-controlled, randomized crossover study. In older lean subjects, CLA/n-3-PUFA supplementation reduced fasting nonesterified fatty acids (NEFAs) concentrations compared with the control oil (P < 0.05). However, in older obese subjects, CLA/n-3-PUFA increased fasting low-density lipoprotein cholesterol (P < 0.05) and postprandial total cholesterol levels (P < 0.05). In young lean subjects, CLA/n-3-PUFA reduced postprandial NEFA levels (P < 0.05) whereas in young obese subjects, postprandial total cholesterol and triacylglycerols were lowered (both P < 0.05). Therefore, a dietary combination of CLA together with n-3-PUFA may have favorable effects on plasma lipids in young and older lean men but detrimental effects in older obese men.

PRACTICAL APPLICATIONS

This study suggests that where individuals consume a combination of both omega-3 polyunsaturated fatty acids and conjugated linoleic acid supplements in order to obtain potential additive beneficial effects of each lipid on adiposity and health, this particular fatty acid combination may have harmful effects on plasma lipid biomarkers of cardiovascular disease in older obese men.