Cardiovascular Risk: DHA Supplements Help Reduce Heart Rate

Supplementation with EPA and DHA can lower heart rate, which is the number of heartbeats per minute—a parameter that, if too high, can represent a cardiovascular risk factor. Treatment with omega-3 supplements is associated with an average reduction in resting heart rate of more than 2 bpm (beats per minute), and when analyzed individually, DHA has a greater effect than EPA. Therefore, omega-3 supplements could represent a simple strategy to reduce overall mortality and the risk of heart disease, especially for those who do not regularly consume fish in their diet.

This emerges from a meta-analysis study published in the European Journal of Clinical Nutrition conducted by a team of researchers from Soochow University (China).

Effects of Omega-3 on Cardiovascular Health

The results of this new study join those of numerous researches, starting from the 1970s thanks to Dr. Jorn Dyerberg, that have highlighted the role of omega-3s in reducing cardiovascular risk. EPA and DHA are linked to a series of positive effects on heart and vessel health, ranging from improvement in blood lipid levels, reduction in blood pressure and heart rate, and thus lowering the risk of coronary disease and cardiac death.

The potential cardioprotective effects of marine-derived omega-3 fatty acids and fish intake have been the subject of many studies, especially concerning sudden cardiac death. A recent meta-analysis published in Mayo Clinic Proceedings indicated that EPA and DHA obtained from food and supplements can reduce the risk of coronary disease.

Specifically, data from 18 clinical trials indicated that omega-3s were associated with a 6% reduction in coronary disease risk across all populations, while the risk reduction increased up to 18% when analyzing data from 16 prospective studies, where individuals who habitually consumed or did not consume omega-3s were followed.

Clinical trial results, where omega-3s or placebo were administered to two groups, also showed a statistically significant reduction in the likelihood of coronary disease in higher-risk subjects: 16% in those with high triglycerides and 14% in those with elevated LDL cholesterol. A 2014 meta-analysis reported that untreated hypertensive subjects had an average reduction in systolic and diastolic blood pressure of 4.51 mmHg and 3.05 mmHg, respectively, associated with omega-3s. In 2012, a meta-analysis by Chinese researchers revealed an association between 56 days of omega-3 supplementation and a 2.3% improvement in flow-mediated dilation, a measure indicating blood vessel ability to relax and thus vessel “health.” As mentioned, data from various studies show that consuming fatty fish or fish oil supplements reduces the risk of sudden cardiac death.

Although the exact physiological mechanisms behind this preventive effect remain unclear, it has been suggested that omega-3s may exert protective action against cardiac death by lowering heart rate, which is the number of heartbeats per minute. Elevated resting heart rate represents a potential risk factor for cardiovascular morbidity and mortality. A study conducted among physicians without pre-existing cardiovascular disease revealed that those who consumed fish at least once a week had a lower risk of sudden cardiac death. Moreover, blood omega-3 reference levels were inversely associated with sudden cardiac death in this population.

DHA Significantly Reduces Heart Rate

For the meta-analysis—a statistical study including results from multiple researches—researchers collected data from 51 studies that met their inclusion criteria, encompassing about 3,000 people in total. All selected studies tested the ability of omega-3 EPA and DHA to reduce heart rate and were found using specific databases such as PubMed. The meta-analysis results indicate that omega-3 supplementation is associated with a significant reduction in heart rate, with effects more attributable to DHA than EPA. Specifically, data showed that compared to placebo, omega-3 supplementation was associated with a slight but significant average reduction in heart rate of 2.23 beats per minute.

When researchers analyzed studies evaluating EPA and DHA separately, they found DHA was associated with an average heart rate reduction of 2.47 bpm, while no statistically significant reduction was observed for EPA alone. According to the study authors, this meta-analysis provides important and updated clinical evidence demonstrating the effect of omega-3 supplementation on reducing heart rate.

As scientists emphasized, it should be considered that the heart rate of most participants included in this study was within the normal range. However, at the population level, the reduction in heart rate could have important public health implications, as a reduction of 3.2 bpm roughly corresponds to a 7.5% decrease in the risk of sudden cardiac death.

Toward More In-Depth Research

According to the Chinese researchers, the new study provides updated evidence on heart rate reduction thanks to omega-3 supplementation, although this chronotropic effect is attributable only to DHA.

Despite some limitations, the results obtained may have valuable clinical and public health implications; omega-3 supplements could represent a lifestyle factor useful to reduce mortality and heart disease risk, especially in those who do not consume enough fatty fish. Therefore, future investigations are needed to evaluate whether heart rate reduction is associated with patient improvements or a better public health profile.

Source: K. Hidayat, et al. “Effect of omega-3 long-chain polyunsaturated fatty acid supplementation on heart rate: a meta-analysis of randomized controlled trials”. European Journal of Clinical Nutrition. risk of coronary disease and cardiac death