Effect of sodium restriction and fish oil supplementation on BP and thrombotic risk factors in patients treated with ACE inhibitors

Abstract

Effects of dietary sodium restriction combined with fish oil supplementation on BP and related risk factors were assessed in hypertensives treated with angiotensin converting enzyme (ACE) inhibitors. After a four week run-in phase, a six week intervention trial was conducted in which four matched groups of 14 patients, taking either captopril or enalapril, were assigned to one of four dietary treatments: low sodium (80 mmol/day) with fish oil (5 g of omega-3 fatty acids per day); normal sodium (150 mmol/day) with fish oil; low sodium with olive oil; normal sodium with olive oil. All subjects adopted a low sodium diet and adjustments of nutrient intake were made by double-blind administration of sodium and oils in supplementary tablets and capsules. BP fell in all treatment groups during intervention. However, the reduction of SBP was 4.2 mmHg greater in subjects on a low sodium intake than in those taking normal sodium. There were no differences in BP between those taking olive oil and those taking fish oil but plasma triglycerides and serum thromboxane production were reduced by 27% and 51%, respectively in the latter. Thus the antihypertensive effect of ACE inhibitors can be augmented by sodium restriction alone but supplementing the diet with fish oil may yield additional cardiovascular benefits.