The real story of omega-3s in heart health

On March 31, The New York Times published an article titled, “Fading claims on fish oils.” The article suggests that the majority of clinical trials measuring effects of fish oil have found “no evidence that fish oil lowers risk for heart attack or stroke.” An important question the article did not address is, “What are the heart health benefits of fish oil?” Here is a more complete answer to that question.

The EPA and DHA omega-3s found in fish oils are just like any other nutrient—they are important for your whole body and are a basic part of human nutrition and a building block for every cell membrane in our body.  Experts believe, based on numerous gold-standard research studies, that omega-3s EPA and DHA are good for heart health.  Let’s look at what the science says:

Reducing Cardiovascular Death Risk

Cardiovascular disease is caused by many factors, including genetics, level of exercise and diet quality. A single factor, like consumption of omega-3s, is not going to completely prevent cardiovascular issues or death. However, taking omega-3s may reduce overall risk. Every meta-analytical review published in the last 10 years that considered the whole body of human clinical evidence for cardiac or coronary death consistently finds a significant benefit to omega-3 consumption. I pulled the data from all of these studies into the table below. The results have shown fish oil consumption reduces cardiac death risk between approximately 10% and 30%:

 

Meta-Analysis	Number of Studies	Coronary Death Risk Reduction
Wen et al, 2014	14	12%  (p=0.003)
Casula et al, 2013	11	32%  (p<0.05)
Kotwal et al, 2012	20	14%  (p=0.03)
Rizos et al, 2012	20	9%  (p=0.01)
Kwak et al, 2012	14	9%  (p<0.05)
Chen et al, 2011	10	19%  (p<0.05)
Marik et al, 2009	11	13%  (p=0.002)
Zhao et al, 2009	8	29%  (p=0.05)
Leon et al, 2008	11	20%  (p=0.002)
Wang et al, 2006	4	35% (p<0.05)

 

Maintaining a Healthy Blood Pressure

Elevated blood pressure is a significant risk factor for heart disease.  If you are diagnosed with high blood pressure, most people know you should make simple lifestyle changes, like reducing sodium intake, exercising and limiting alcohol consumption. The most recent meta-analysis of EPA/DHA’s impact on blood pressure found that fish oil can reduce systolic blood pressure by approximately the same amount as lifestyle interventions in people who are not being treated with pharmaceutical drugs for high blood pressure. The table below compares the systolic blood pressure effect from this study to that of these other lifestyle changes, as reported in a 2006 study by Dickinson et al.   

Lifestyle Intervention	Blood Pressure Reduction*
Consuming EPA and DHA omega-3s	4.5 mm Hg
Reduced dietary sodium	3.6 mm Hg
Increased physical activity	4.6 mm Hg
Decreased alcohol consumption	3.8 mm Hg

* Values represent average reductions in systolic blood pressure (SBP) as effects of various lifestyle interventions and omega-3 consumption in untreated hypertensives

The study also found that EPA and DHA could slightly reduce diastolic blood pressure and even benefit people who don’t have high blood pressure. This is important because blood pressure is one of the few causal risk factors for cardiovascular disease, so reducing blood pressure can have a significant impact on coronary heart disease risk.

The meta-analysis was a comprehensive study that analyzed the results from 70 of the gold-standard randomized, double-blind, placebo-controlled clinical trials.  Meta-analyses this large are rare in the nutrition field, so the significance of the effect is important.   For full disclosure, this meta-analysis was funded by GOED, but conducted by independent researchers and published in the American Journal of Hypertension, a top-tier peer-reviewed journal.

 

Maintaining Healthy Triglyceride Levels

Triglycerides are an emerging risk factor for cardiovascular disease and are part of your total cholesterol calculation. The American Heart Association notes that 31% of Americans have borderline high triglycerides or higher, so it is a problem that needs to be addressed on a large scale. EPA and DHA are so effective at lowering triglycerides that the FDA has approved three high-dose, fish oil-derived pharmaceuticals for people with very high triglycerides.  On average, fish oil supplementation lowers fasting triglycerides by 30-40%.  The evidence on the beneficial effects of EPA and DHA consumption on triglyceride levels is very convincing and consistent. To date, 22 meta-analyses of clinical trials have been published looking at the triglyceride-lowering effects of EPA and DHA, and every single one has concluded that they reduce triglyceride levels. The effect has been observed in healthy people, diabetics, cardiovascular disease patients, people with HIV, kidney transplant patients, and more, so the benefits are widespread throughout the population.

How did The New York Times come to a different conclusion, then?

The conclusions that were drawn in the article focus on the potential benefits of fish oil for treating specific cardiovascular diseases in populations with advanced disease. Remember, that except for three approved drugs for treating very high triglycerides, EPA and DHA omega-3s are nutrients. They are not used for treating diseases, but instead they help improve nutrition and health.

There are many factors that contribute to heart health, and getting enough omega-3s is one of those factors. The evidence consistently shows that EPA and DHA omega-3s reduce risk of cardiac death, help maintain healthy blood pressure, and keep triglycerides in check.

Unfortunately, most Americans do not eat enough of the right kinds of fatty fish, like salmon, mackerel and sardine, to get recommended amounts of omega-3s. Eating enough omega-3-rich fish and/or taking supplements are healthy habits everyone should follow. A healthier diet also means a healthier heart.