Many randomised clinical trials have shown that omega-3s can reduce blood pressure and produce other heart-health benefits
Omega-3 fatty acids are good for health — especially heart health. So good, in fact, that current dietary guidelines encourage people to consume at least half a gram per day of a combination of the omega-3s eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). That recommendation goes up to 1g a day for people with diagnosed cardiovascular disease.
Many randomised clinical trials have shown that omega-3s can reduce blood pressure and produce other heart-health benefits. However, these studies have mostly been based on much larger doses than those noted above. The majority have used dosages greater than 3g per day, which are hard to attain through diet alone.
A double-blind, randomised, placebo-controlled, dose-response, crossover study trial published in the Journal of Nutrition in 2016 sought to determine whether levels of EPA+DHA achievable through diet could have an impact on blood pressure and microvascular function.
The trial included 312 healthy men and women who were randomly assigned to one of three arms consisting of a 3.2g control oil (80:20 mixture of palm oil and soybean oil) or 3.2g of fish oil providing 1.8g of EPA+DHA (as 1.4 ratio of DHA to EPA), or a 50:50 mixed control oil and fish oil providing 0.7g of EPA +DHA. Each participant was assigned each of the interventions (one at a time) for 8 weeks each. Fasting blood pressure and microvascular function were assessed.
The researchers found that fish oil consumption in either dosage was associated with a statistically significant reduction in systolic blood pressure (5mm HG) in people with isolated systolic hypertension.
The minimum dosage that had an effect — 0.7g a day — is easily achieved by eating two to three portions of oily fish per week. The 5mm HG reduction in systolic blood pressure has the potential to reduce cardiovascular disease risk in middle age by about 20%. The fact that such a moderate amount of fish consumption can have such a significant impact on heart disease risk is encouraging.