Does fish oil lower blood pressure
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The Impact of Fish Oil on Blood Pressure: A Comprehensive Review
Introduction to Fish Oil and Blood Pressure
Fish oil, rich in omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been widely studied for its potential cardiovascular benefits, including its effects on blood pressure (BP). This article synthesizes findings from multiple research studies to determine whether fish oil can effectively lower blood pressure.
Meta-Analyses and Systematic Reviews on Fish Oil and Blood Pressure
Meta-Analysis Findings
A meta-analysis of 31 placebo-controlled trials involving 1356 subjects found that fish oil supplementation resulted in a mean reduction in blood pressure of -3.0/-1.5 mm Hg1. The analysis highlighted a dose-response relationship, with higher doses of fish oil leading to more significant reductions in BP. Specifically, doses of less than 3 g/day resulted in a reduction of -1.3/-0.7 mm Hg, while doses of 15 g/day led to a reduction of -8.1/-5.8 mm Hg1.
Systematic Review Insights
A systematic review of 17 studies with 1524 participants also supported the BP-lowering effects of fish oil, particularly in hypertensive individuals. The review found a statistically significant reduction in systolic BP by 2.56 mm Hg and diastolic BP by 1.47 mm Hg in hypertensive participants3. However, the effects were modest and not significant in normotensive individuals3.
Specific Populations and Conditions
Hypertensive and Older Adults
Research indicates that fish oil is particularly effective in older adults and those with hypertension. A metaregression analysis of 36 trials found that fish oil reduced systolic BP by 2.1 mm Hg and diastolic BP by 1.6 mm Hg, with more pronounced effects in older and hypertensive populations2. Another study showed that even low doses of EPA and DHA (0.7 g/day) could significantly reduce systolic BP by 5 mm Hg in individuals with isolated systolic hypertension6.
Normotensive Individuals
In contrast, studies involving normotensive individuals have generally shown minimal or no significant BP-lowering effects. For instance, a study involving 350 normotensive participants found no significant differences in BP changes between those taking fish oil and those taking a placebo8. Similarly, another study with 18 mildly hypertensive subjects reported no substantial BP changes with moderate doses of fish oil10.
Combined Dietary Interventions
Fish Oil and Sodium Restriction
Combining fish oil supplementation with other dietary interventions, such as sodium restriction, has shown promising results. A study involving elderly participants found that a low-sodium diet supplemented with fish oil significantly reduced both systolic and diastolic BP7. This suggests that fish oil may be more effective when combined with other BP-lowering dietary strategies.
Conclusion
Overall, the evidence suggests that fish oil can lower blood pressure, particularly in hypertensive and older adults. The effects are dose-dependent, with higher doses leading to more significant reductions. However, the BP-lowering effects in normotensive individuals are minimal. Combining fish oil with other dietary interventions, such as sodium restriction, may enhance its effectiveness. While fish oil shows promise, it should not replace conventional BP-lowering medications but can be considered a complementary approach for managing hypertension.
Sources and full results
Most relevant research papers on this topic
Does Fish Oil Lower Blood Pressure? A Meta‐Analysis of Controlled Trials
Fish oil has a dose-response effect on blood pressure, with the strongest hypotensive effect in hypertensive subjects and those with clinical atherosclerotic disease or hypercholesterolemia.
Meta-Analysis
Highly CitedBlood pressure response to fish oil supplementation: metaregression analysis of randomized trials
High intake of fish oil may lower blood pressure, especially in older and hypertensive individuals, but the antihypertensive effect of lower doses (0.5 g/day) remains to be established.
Meta-AnalysisHighly CitedA systematic review of fish-oil supplements for the prevention and treatment of hypertension
Fish-oil supplements show small but significant reductions in blood pressure in hypertensive individuals, but their modest effects make them a less recommended alternative to blood pressure-lowering drugs.
Meta-AnalysisHighly CitedLack of effect of fish oil supplementation on blood pressure in treated hypertensives.
Fish oil supplementation has a small additional effect on blood pressure in treated hypertensives with controlled blood pressures, making its reduction in antihypertensive drug therapy unlikely.
RCTFish oil affects blood pressure and the plasma lipid profile in healthy Danish infants.
Fish oil supplementation in infants improves blood pressure and lipid profile, similar to adult studies, with long-term health implications warranting further investigation.
RCTHighly CitedConsumption of Fish Oil Providing Amounts of Eicosapentaenoic Acid and Docosahexaenoic Acid That Can Be Obtained from the Diet Reduces Blood Pressure in Adults with Systolic Hypertension: A Retrospective Analysis.
Fish oil containing as little as 0.7g of EPA+DHA can significantly reduce blood pressure in adults with isolated systolic hypertension, potentially lowering cardiovascular disease risk.
RCT
Large Human Trial
Very Rigorous JournalA low-sodium diet supplemented with fish oil lowers blood pressure in the elderly
Dietary fish oil supplementation combined with sodium restriction significantly lowers diastolic blood pressure in the elderly.
RCTHighly CitedShort report : the effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the trials of hypertension prevention
Moderate doses of fish oil (6g/day) are unlikely to lower blood pressure in normotensive individuals, but may increase HDL2-cholesterol, particularly in women.
RCTLarge Human TrialThe effect of fish oil on blood pressure and high‐density lipoprotein‐cholesterol levels in phase I of the Trials of Hypertension Prevention
Moderate doses of fish oil (6g/day) are unlikely to lower blood pressure in normotensive individuals but may increase HDL2-cholesterol, particularly in women.
RCTLarge Human TrialThe effect of fish oil on blood pressure in mild hypertensive subjects: a randomized crossover trial.
Fish oil is not a practical treatment for mild hypertension, as it does not significantly lower blood pressure compared to an olive oil placebo.
RCT