Fish Oil Supplementation Does Not Lower Plasma Cholesterol in Men with Hypercholesterolemia

doi:10.1059/0003-4819-111-11-900

Fish Oil Supplementation Does Not Lower Plasma Cholesterol in Men with Hypercholesterolemia

Results of a Randomized, Placebo-Controlled Crossover Study

Timothy J. Wilt, MD;
Richard P. Lofgren, MD, MPH;
Kristin L. Nichol, MD, MPH;
Anna E. Schorer, MD;
Lori Crespin, MPH;
Deborah Downes, BA, RD; and
John Eckfeldt, MD, PhD

Abstract

Study Objective: To determine the effects of fish oil supplementation on plasma cholesterol in middle-aged men with isolated hypercholesterolemia.

Design: Randomized double-blind placebo-controlled (safflower oil) two-period crossover trial with 12-week treatment periods.

Setting: Outpatient general medicine clinic at a university-affiliated Veterans Affairs hospital.

Patients: Thirty-eight men with plasma cholesterol between 5.68 and 7.76 mmol/L (220 to 300 mg/dL), triglyceride levels less than 3.39 mmol/L (300 mg/dL), and free of coexisting diseases.

Interventions: Fish oil and placebo (safflower oil) supplementation. After basal measurements and a 4-week lead-in period, twenty 1-g capsules of either fish oil or placebo oil were provided for 12 weeks (period 1). After a 4-week washout phase participants then received the other oil for an additional 12 weeks (period 2).

Measurements and Main Results: Blood was drawn at the beginning and end of each study period and analyzed for levels of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1, and apolipo-protein B. Low-density lipoprotein (LDL) cholesterol was calculated using the Friedewald equation. Total and LDL cholesterol increased from the before treatment values by 4.8% and 9.1%, respectively, after ingestion of fish oil. Compared with placebo, LDL cholesterol was significantly higher (4.5 compared with 4.1 mmol/L, P = 0.01) and triglycerides lower (1.3 compared with 1.8 mmol/L, P = 0.01) after fish oil. Total and HDL cholesterol and apolipoprotein A1 and B levels did not differ.

Conclusions: Fish oil supplements do not lower plasma cholesterol levels in middle-aged men with hypercholesterolemia without elevated triglycerides. They should not be recommended as a method to lower plasma cholesterol in these patients.

Article and Author Information

From the Minneapolis Veterans Affairs Medical Center, the University of Minnesota Medical Center, and the School of Public Health of the University of Minnesota, Minneapolis, Minnesota. For current author addresses, see end of text.
Grant Support: Supported in part by grant 0325-2423-15 from the Graduate School of the University of Minnesota and by a special grant award from the Minnesota Medical Foundation.
Requests for Reprints: Timothy J. Wilt, MD, Minneapolis Veterans Administration Medical Center (111-0), 1 Veterans Drive, Minneapolis, MN 55417.
Current Author Addresses: Drs. Wilt, Nichol, and Schorer and Ms. Crespin and Mrs. Downes: Minneapolis Veterans Administration Medical Center, 1 Veterans Drive, Minneapolis, MN 55417.

Dr. Lofgren: University of Pittsburgh, Veterans Administration Medical Center (Oakland) (11G), University Drive C, Pittsburgh, PA 15240.

Dr. Eckfeldt: Box 198 University of Minnesota Health Center, Laboratory Medicine and Pathology, Harvard Street at East River Road, Minneapolis, MN 55455.