By: Adin Smith, MS
Omega-3 fatty acids found in fish (EPA+DHA) are believed to have a positive impact on heart health.1,2 Evidence supporting this claim comes from studies tracking large groups of people and linking higher omega-3 blood levels with a lower risk of major cardiovascular problems.3,4
These findings led the American Heart Association (AHA) to recommend that individuals with poor cardiovascular health consume a minimum of 1 gram of omega-3s from fish or fish oil capsules per day.5
Consuming 500 mg of omega-3 per day is difficult for many, especially for Americans. In fact, about 90% of Americans consume less than the daily recommendation of omega-3s, with 80% not meeting even the minimum daily target of 250 mg recommended in the Dietary Guideline for Americans.6,7
Clearly, Americans could be doing a better job supporting their heart health by consuming more fish, but what about taking fish oil capsules?
A recent (2020) analysis of 40 studies found that supplementing with omega-3 fish oil (up to 5500 mg/day) was linked to a:1
The researchers in this analysis also looked at whether taking higher doses of omega-3 fish oil provided enhanced cardiovascular benefits. They found that the additional intake of 1 gram per day of omega-3 fish oil delivered an additional 9% reduction in heart artery obstruction and a 5.8% reduction in the risk of cardiovascular events.1 These results show that higher doses of omega-3 EPA+DHA may provide additional heart health support.
Although this data is compelling, it’s important to take a broad view of the research. Not all studies looking at the effects of omega-3 supplementation on heart health have reported positive results, and there are some specific influential factors that may help explain why.
Research shows that people must reach a certain level of omega-3s in the bloodstream to benefit from taking omega-3 supplements.8,9 For instance, one study evaluated omega-3 blood levels and cardiovascular health among participants taking 1800 mg per day of omega-3 fish oil for five years.9 At trial end, the individuals achieving omega-3 blood levels above a certain threshold had a 20% lower risk of major cardiovascular problems compared to individuals with omega-3 blood levels below that threshold. Notably, a surprising 40% of the individuals taking 1800 mg per day of omega-3 for five years did not achieve the omega-3 blood level required to make a significant difference in heart health.
These findings suggest that 1800 mg of omega-3 fish oil per day can effectively raise omega-3 blood levels enough to promote heart health for some people, but that higher doses are implicated for many others.
Certain health factors may lead to lower omega-3 levels in the body. For instance, researchers recently found that omega-3 blood levels were much lower among overweight individuals than normal-weight individuals—despite both groups having an equal dietary intake of omega-3s.10 This would suggest that some people need to consume omega-3s in much higher amounts to achieve the blood levels necessary for supporting heart health.
Other health factors linked to lower levels of omega-3 in the body include:
Based on this list of health factors, many people will need to increase their intake of the omega-3 fatty acids (EPA+DHA). Adding daily EPA+DHA capsules or liquids to the diet is a practical option for many and offers a number of important advantages for heart health.
Platelets are small cells in the bloodstream responsible for blood clotting. When injury occurs, these tiny cells coordinate by sticking together to form clots. While blood clotting is vital for tissue repair, chronic elevations in platelet activity may lead to poor cardiovascular health.23
For instance, researchers measured platelet activity in healthy men and women and tracked them for 20 years to see who developed a heart attack or stroke.24 At the trial end, those with elevated platelet activity had a 68% higher risk of heart attack or stroke than those with normal platelet activity.
Roughly two decades ago, researchers looked to see if omega-3 intake might lead to platelet activity changes.25 As it turns out, increasing omega-3 intake results in higher concentrations of omega-3 EPA+DHA within the body’s platelets.26 An extensive analysis of several studies later reported that individuals taking omega-3 supplements had significant platelet activity reductions compared to the placebo group.26 These results suggest that omega-3 intake plays a vital role in supporting healthy platelet activity.
Excess buildup of fat, cholesterol, and other blood substances can lead to plaque buildup and poor artery health. In a study evaluating the effects of omega-3 on artery plaque in those with poor artery health, participants were assigned to receive 3360 mg of omega-3 fish oil or no omega-3 for 30 months to measure differences in plaque progression.27 Upon completion, the participants supplementing with omega-3 fish oil who achieved higher blood levels of omega-3 had no signs of plaque progression. In contrast, all participants with lower omega-3 blood levels experienced worsening artery health—even among those taking supplements.
These results suggest that levels of omega-3s within the body need to reach a certain threshold to maintain optimal heart health. Notably, this evidence also indicates that doses greater than roughly 3500 mg per day are needed to make a significant difference in heart health among those with unhealthy arteries.
Triglycerides are an important type of fat (lipid) in the blood that help support the body’s energy needs. However, excessive amounts of these blood fats may lead to poor cardiovascular health. Several studies show that supplementing with omega-3 fish oil supports healthy triglyceride levels.28 For instance, a 12-week study analyzing the effects of omega-3 supplements on triglycerides found that compared to placebo, individuals supplementing with 4000 mg per day increased their omega-3 blood levels by 650% and had roughly 21% healthier blood fat levels.29,30 A recent review from the American Heart Association also found that 4000 mg per day of omega-3 EPA can promote healthier triglyceride levels by 30% or more among people with high amounts of blood fats.31
Research shows that individuals with healthy blood pressure also tend to have higher omega-3 blood levels.32,33 When responding to stress, healthy blood vessels dilate (expand), which increases blood flow and lowers blood pressure. In contrast, individuals with poor blood vessel dilation have an increased risk of cardiovascular events.34 Many studies report that omega-3 fatty acids help maintain healthy blood pressure ranges by supporting artery dilation.35,36
For instance, in a 12-week study measuring the effects of omega-3 on artery health, participants taking 2000 mg per day of EPA+DHA had greater increases in artery flexibility and dilation than the placebo group.37 These results suggest that omega-3 fatty acids have artery-supportive properties that help the body’s blood vessels adapt to physical stressors. And indeed, a recent analysis of 20 trials reported that omega-3 supplements helped support healthy blood pressure ranges —especially for the participants with high triglyceride levels.38
The number of times your heart beats per minute while at rest is an indicator of cardiovascular health.39 A resting heart rate between 60-100 beats per minute (bpm) is considered normal, but some experts believe ideal rates range between 50-70 bpm or less.39,40 In fact, people with resting heart rates over 70 bpm are more likely to have artery narrowing, high blood pressure, and many other cardiovascular problems.40 In contrast, people with the highest fitness levels typically have healthier arteries and resting heart rates below 60 bpm.39
People with a higher dietary intake of omega-3s also tend to have lower resting heart rates.41 For instance, an analysis of 51 studies reported that those supplementing with omega-3 fish oil had lower resting heart rates than participants taking a placebo pill.42 This research suggests that a higher intake of omega-3 fatty acids supports a healthy resting heart rate.
The research reviewed throughout this article suggests that people with low omega-3 blood levels are particularly vulnerable to heart-related problems and cardiovascular risk factors (i.e., high blood pressure, higher resting heart rate, high blood fat levels) and that a higher omega-3 status is associated with greater cardiovascular health. Importantly, the evidence also shows that achieving higher omega-3 blood levels is necessary for enjoying the heart health benefits of omega-3s. Based on the research reviewed here, consuming at least 2000 mg of omega-3s (EPA+DHA) per day can provide adequate cardiovascular support for most people. However, we encourage you to speak with a healthcare professional about the dosage implicated by your specific heart-health needs.
Adin Smith, MS is a Science Researcher and Writer for Nordic Naturals. He holds a Masters Degree in Nutrition, and believes that many health conditions are the result of suboptimal nutrient status. For this reason, Adin is committed to informing others about the latest research in nutrition, lifestyle modification, and dietary supplements.
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