Reduction of blood pressure and plasma triglycerides by omega-3 fatty acids in treated hypertensives.
OBJECTIVE
To assess the effects of omega-3 (n-3) fatty acid supplementation on blood pressure and plasma lipids in hypertensives treated with diuretics or beta-blockers.


METHODS
Double-blind placebo-controlled cross-over trial consisting of a 4-week run-in phase and two 6-week intervention phases.


METHODS
A total of 43 patients of either sex taking a beta-blocker only (n = 29), a diuretic only (n = 3) or a beta-blocker plus diuretic (n = 11) for hypertension were recruited from general practice. One patient from the latter group was withdrawn.


METHODS
Seated blood pressure was measured every 2 weeks in the clinic with a Dinamap. After the run-in phase, participants were randomly assigned to take a supplement of either Omacor (85% n-3 fatty acid concentrate) or corn oil (four 1-g capsules/day) for 6 weeks, after which they crossed over to the other supplement. Fasted blood samples were taken at the end of each phase for lipid analysis.


METHODS
The within-individual differences in systolic and diastolic pressure and plasma lipids between Omacor and corn oil treatment.


RESULTS
Systolic/diastolic blood pressures measured during the run-in phase were normal (132 +/- 2/76 +/- 1 mmHg, n = 42) but decreased further with n-3 fatty acid supplementation. The mean within-individual difference in blood pressure compared with corn oil supplementation was 3.1 +/- 1.0/1.8 +/- 0.6 mmHg (P < 0.01). This was accompanied by a 21% reduction in plasma triglycerides (P < 0.01) and a 15% increase in high-density lipoprotein-2 cholesterol (P < 0.01) but there were no significant differences in total or low-density lipoprotein cholesterol.


CONCLUSIONS
The antihypertensive and hypotriglyceridaemic effects of n-3 fatty acid supplementation seen in the present study suggest that it may be a useful adjunct to antihypertensive therapy with beta-blockers or diuretics.
CSIRO Division of Human Nutrition, Adelaide, South Australia.
Y K
YK
Lungershausen
M
M
Abbey
P J
PJ
Nestel
P R
PR
Howe
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D004042:Dietary Fats, Unsaturated; D004232:Diuretics / Q000627:therapeutic use; D004311:Double-Blind Method; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy*; D007206:Individuality; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood*
D000319:Adrenergic beta-Antagonists; D004042:Dietary Fats, Unsaturated; D004232:Diuretics; D015525:Fatty Acids, Omega-3; D014280:Triglycerides