Blood pressure-lowering effects of long chain n-3 fatty acids from meals enriched with liquid fish oil and from microencapsulated powder

Background: Diet plays an important role in the etiology of hypertension. Blood pressure (BP)-lowering properties of long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) are promising. The aim was to investigate whether different formulations of fish oil differently affect blood pressure in community-dwelling adults. The hypothesis was that fish oil formulations would improve BP in comparison with a placebo.Methods: In this 4-week randomized, placebo-controlled, doubly-blinded dietary intervention study, participants (N=99,>50 years) from the capital area of Iceland were randomized into three groups. Group 1 (n=38) received 6 meals/week fortified with a liquid fish oil and placebo powder. Group 2 (n=30) received conventional (unfortified) meals and microencapsulated powder. Group 3 (n=31) was the control group which received conventional meals and placebo powder. Calculated on a weekly basis, the amount of EPA+DHA provided was 1.5g/d. Systolic (SBP) and diastolic BP (DBP) were measured before and after the intervention period.Results: Seventy-seven subjects finished the study (77.8%). Drop-out rates were not different between groups. According to multivariate statistics, endpoint SBP was lower in Group 1 (-7.0mmHg, p=0.037) and in Group 2 (-7.2mmHg, p=0.037) as compared with Group 3. There was no significant difference in DBP between the groups.Conclusion: Our study shows that LC n-3 PUFA from microencapsulated powder are equally effective to meaningfully reduce SBP as LC n-3 PUFA from meals enriched with liquid fish oil in comparison with a control group.