Diabetes Care, Vol 17, Issue 1 37-44, Copyright © 1994 by American Diabetes Association
Effects of a small quantity of omega-3 fatty acids on cardiovascular risk factors in NIDDM. A randomized, prospective, double-blind, controlled study
L Axelrod, J Camuso, E Williams, K Kleinman, E Briones and D Schoenfeld
Diabetes Unit, Massachusetts General Hospital, Boston 02114.
OBJECTIVE--To study the effects of a low dose of omega-3 fatty acids on
platelet function and other cardiovascular risk factors in patients with
non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND
METHODS--We performed a randomized, prospective, double-blind, controlled
study of a low dose of omega-3 fatty acids (2.5 g/day) in 20 ambulatory
subjects with NIDDM. Subjects ingested five 1-g fish oil capsules each
containing 0.5 g omega-3 fatty acids or five 1-g safflower oil capsules per
day for 6 weeks followed by a 6-week washout period. RESULTS--Nine subjects
completed the study in each group. Both groups exhibited moderate control
of glucose levels; modest elevations in baseline total cholesterol,
low-density lipoprotein (LDL) cholesterol, and triglyceride (TG) levels;
and normal blood pressure values. In the fish oil group, plasma omega-3
fatty acid levels increased significantly. Fish oil significantly reduced
the slope of the dose-response curves for collagen-induced platelet
aggregation to one-third the value observed with safflower oil. No
difference was observed in collagen-induced production of thromboxane A2
(TXA2, measured as the stable derivative TXB2), or in
adenosine-5'-diphosphate- (ADP) induced platelet aggregation or TXA2
generation. Patients with high initial collagen-induced platelet TXA2
production showed a significantly larger drop after fish oil than safflower
oil. Fish oil significantly reduced TG levels by 44 mg/dl and decreased
upright systolic blood pressure (sBP) by 8 mmHg compared with safflower
oil. Fish oil caused a significant but small increase in HbA1c (0.56%) and
total cholesterol (20 mg/dl) but had no effect on fasting glucose,
high-density lipoprotein cholesterol, or LDL-cholesterol levels.
CONCLUSIONS--Small doses of fish oil inhibit platelet aggregation and TXA2
production, reduce upright sBP and TG levels, and have only a small effect
on glucose and cholesterol levels in patients with moderately controlled
NIDDM. Small quantities of omega-3 fatty acids or dietary fish are safe and
potentially beneficial in NIDDM patients.