Omega-3, -6, and -9 Fatty Acid Supplements Exert Different Effects on Serum Lipid Concentrations in Renal Dialysis Patients
■ Objective: To compare changes in blood lipid profiles of renal dialysis patients who consumed diets rich in either omega-3, -6, or -9 fatty acids over a 6-week period. ■ Design: Randomized before-after trial. ■ Setting: Three dialysis centers in the Dallas, TX, area. ■ Patients: Thirty-five maintenance hemodialysis patients were selected. Twenty-eight (9 men and 19 women) completed the study. Subjects were identified for inclusion for the study by the following criteria: concentrations of triglycerides (> 150 mg/dL) and cholesterol (> 180 mg/dL), absence of insulin-dependent diabetes, and absence of liver disease defined as three times greater than normal levels of serum glutamic pyruvic transaminase and serum glutamic oxaloacetic transaminase. ■ Interventions: Patients were given a daily supplement of either omega-3 fatty acid (3 g) MaxEPA (Seven Seas Health Care, Hull, England), omega-6 fatty acid (3 g) cottonseed oil, or omega-9 fatty acid (10% of caloric intake) pecan oil. ■ Main outcome measures: Fasting blood samples were obtained on days 0, 21, and 42 to determine serum total cholesterol (TChol), high-density lipoprotein cholesterol (HDL-C), HDL subfractions (HDL 2 -C and HDL 3 -C), and triglycerides (TG). ■ Results: A significant decrease in serum TChol was observed in the omega-9 fatty acid group. Significant decreases were also observed in the serum TG concentrations of the omega-3 and omega-9 fatty acid groups. Significant decreases in HDL-C were observed in the omega-3 fatty acid and control groups, whereas significant decreases in the HDL -C occurred in the control group. The HDL-C reduction in the omega-3 fatty acid group occurred primarily in the HDL -C subfraction. ■ Conclusions: Omega-3, -6, and -9 fatty acid supplements exert different effects on the serum lipid profiles of renal dialysis patients. New studies need to be initiated to determine the mechanisms responsible for this altered lipid metabolism and the clinical significance of these changes.