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Fish oil capsules are a source of omega-3 fatty acids, but experts have some words of caution about supplementation. HUIZENG HU/Getty Images
  • Researchers are recommending people consume 3 grams of omega-3 fatty acids per day to help lower blood pressure.
  • Experts say the best source for these acids is fresh fish such as salmon and tuna.
  • They note there are some plant-based alternatives such as walnuts and chia seeds, too.
  • They say using supplements such as fish oil can be beneficial if fresh fish isn’t available, but they do have some cautions about relying on supplements.

Lowering your blood pressure with omega-3 fatty acids may be possible, but how many grams a day does it take to make a difference?

Until now, there was no clear answer.

The National Institutes of Health says an adequate daily amount is between 1.1 and 1.6 grams for adults, depending on factors such as age and gender.

However, a new research review published in the Journal of the American Heart Association suggests the optimal daily dose for lowering blood pressure is 3 grams of omega-3s.

The researchers say the omegas can be from supplements or fatty fish, such as salmon, tuna, sardines, trout, herring, and oysters.

The study was funded by the Macau Science and Technology Development Fund and Faculty Research Grants of the Macau University of Science and Technology.

Among the key findings are:

  • People who consumed between 2 and 3 grams daily of combined DHA and EPA omega-3 fatty acids demonstrated reduced systolic (top number) and diastolic (bottom number) blood pressure by an average of about 2 mm Hg.
  • Systolic blood pressure decreased by an average of 4.5 mm Hg for those with hypertension and about 2 mm Hg on average for those without.

The reviewers noted that consuming more than 3 grams of omega-3 fatty acids daily may have additional blood pressure-lowering benefits for adults at a higher risk of heart disease.

For example, they said that with 5 grams a day of omega-3s, systolic blood pressure declined an average of nearly 4 mm Hg for those with hypertension and less than 1 mm Hg on average for those without.

Larger declines in blood pressure were also seen in people with high blood lipids and among those older than age 45.

Three grams per day was established as the optimal dose after researchers examined the relationship between blood pressure and the omega-3 fatty acids DHA and EPA (either individually or combined) in people aged 18 and older with or without high blood pressure or cholesterol disorders.

Overall, they reviewed 71 clinical trials published globally from 1987 to 2020, including nearly 5,000 participants ranging in age from 22 to 86 years. Participants took dietary and/or prescription supplement sources of fatty acids for an average of 10 weeks.

The researchers said the study aligns with the Food and Drug Administration (FDA) statement that there is some credible evidence that EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease by lowering high blood pressure, especially among people already diagnosed with hypertension.

However, they noted that although their study adds a layer of evidence in the case for omegas lowering blood pressure, it does not meet the threshold to make an authorized health claim for omega-3 fatty acids in compliance with FDA regulations.

Kristin Kirkpatrick, MS, RDN, a nutritionist and the author of “Skinny Liver,” says she recommends consumption of DHA and EPA from fatty fish in the same approximate amounts in about 2 servings per week, which would be more than adequate for the 3 grams recommended.

“If cost is a concern as it pertains to eating fish, try farm or ocean-raised versus wild, which is typically much less expensive and still provide a high intake of omega 3s,” said Lon Ben-Asher, MS RD, LDN, a nutritionist at Pritikin Longevity Center.

He also suggests adding avocado and edamame beans to your meals.

Christina Meyer-Jax, MS, RDN, LDN, a health advisor for Lifesum, says when she works with clients, she encourages a whole foods diet that focuses on a balance of healthy fats.

A whole foods diet in this case means obtaining omega-3s from fatty fish, nuts, and seeds will provide the variety of omega-3 fatty acids that are needed for overall health, she notes.

“Supplements should only be consumed if you can’t get an adequate intake of nutrients to meet the body’s demands. There is a nutrient deficiency with symptoms present affecting one’s health, as well as if an individual has a malabsorptive disorder,” Ben-Asher told Healthline.

Otherwise, he says, stick to the whole fish, which provides an adequate amount of omega-3s and is more easily absorbed and used in the body.

If you do need supplementation, here’s what Meyer-Jax told Healthline she recommends:

  • Find a balance of omega-3s (ALA, DHA, EPA) but with concentrations of DHA and EPA are at higher levels overall.
  • Check that the supplements are made from quality fish and that they are being produced by a supplement manufacturer that follows or even exceeds the FDA’s Good Manufacturing Practices guidelines.
  • Look for third-party certification.
  • Add in supplements slowly to allow for your body to adjust and to see how your body responds.

The risk for taking 3g of omega-3 supplementation is low for the general population, says Kirkpatrick, but if someone is on medications to thin blood, for example, then having excess omega 3 supplementation for example could thin blood further.

Therefore, “if a supplement is what the patient is interested in, I would look at all other factors first. Like most things, keeping levels to moderate is often the best approach,” says Kirkpatrick.

Meyer-Jax agrees, saying each individual may respond differently to supplements which are often at much higher levels of nutrients, including omega-3s, than eating foods that contain them.

“More is not always better and it’s good to consult with a registered dietitian or physician who will understand other factors that could affect whether a person should take the supplements,” she said.

Omega 3’s are traditionally found in fatty fish such as salmon and tuna. However, there are also many plant-based sources, says Kirkpatrick.

Some people, says Meyer-Jax, may not be able to take fish oil supplements due to allergies. These persons may need to use algae and flax-based omega-3 supplements instead.

Kirkpatrick told Healthline she encourages people to get their omega’s through a variety of sources to obtain the greatest spectrum of nutrient density.

Examples of plant-based sources of omega-3 fatty acids include:

  • Walnuts
  • Chia seeds
  • Algae
  • Flax seeds