No seafood or supplements: Walnuts and plant-based omega-3s can also boost heart health

UNIVERSITY PARK, Pa. — Omega-3 fatty acids have become wildly popular because of their benefits to the cardiovascular system, keeping the heart healthy and protecting against stroke. Many people eat more salmon and other oily fish if they’re looking to take in more omega-3, but what if you’re just not that into seafood or supplements? Researchers from Penn State are offering up a fatty acid alternative — plants.

Their study finds a plant-based version of omega-3, called alpha-linolenic acid (ALA), can protect heart health and reduce heart disease risk among people who avoid seafood.

Through a comprehensive review, the research team discovered that eating the ALA from various plant-based foods like walnuts and flaxseeds contributed to a 10-percent decline in cardiovascular disease risk and a 20-percent lower risk of fatal coronary heart disease.

“People may not want to eat seafood for a variety of reasons, but it’s still important for them to consume omega-3s to reduce the risk of heart disease and to promote overall health,” study co-author Kris-Etherton says in a university release. “Plant-based ALA in the form of walnuts or flaxseeds can also provide these benefits, especially when incorporated into a healthy diet rich in fruits, vegetables, and whole grains.”

Moreover, the analysis suggests people who avoid seafood altogether stand to benefit even more than others by eating plant-based omega-3s.

“When people with low levels of omega-3s in their diet ate ALA, they saw a benefit in terms of cardiovascular health,” adds study co-author Jennifer Fleming, an assistant teaching professor of nutrition at Penn State. “But when people with high levels of omega-3s from other sources ate more ALA, they also saw a benefit. It could be that ALA works synergistically with other omega-3s.”

Most omega-3 studies only look at fish oil

While several prior studies have found that omega-3 likely lowers heart disease risk, all of those focused primarily on fatty acids coming from fish oil. In comparison, very little research has examined the benefits of ALA.

So, researchers decided to analyze datasets collected by earlier projects, all in the hopes of accurately assessing the impact of ALA on heart disease and heart disease risk factors like blood pressure and inflammation. Those earlier studies featured both randomized controlled trials and observational projects.

While some of the observational studies asked participants to report how often they ate certain foods, others relied on biomarkers (an avenue of measuring ALA levels in the blood) as a more accurate strategy.

“With the advent of precision nutrition and personalized medicine, we are more aware than ever of the need to identify and target individuals who might get the largest benefit from increasing their consumption of ALA-rich foods,” says lead study author Aleix Sala-Vila, a researcher at the Institut Hospital del Mar d’Investigacions Mèdiques–Barcelona. “Paying close attention to the amount of ALA in the blood and how it affects heart health could help in this effort.”

How many walnuts do I need for better heart health?

All in all, the analysis suggests ALA offers “beneficial effects” in reference to reducing atherogenic lipids, lipoproteins (total cholesterol, low density-lipoprotein cholesterol, and triglycerides), inflammation, and blood pressure. According to Emilio Ros, emeritus investigator at Institut d’Investigacions Biomèdiques August Pi Sunyer, a research institution linked to Hospital Clínic of Barcelona and Barcelona University, this may partially explain why ALA benefits the heart.

“We were able to find evidence supporting current dietary guidelines that ALA should provide about 0.6%–1% of total energy in a day, which is about 1.1 grams a day for women and 1.6 grams a day for men,” Ros concludes, “and can be incorporated into the diet with foods such as walnuts, flaxseeds, and cooking oils such as canola and soybean oils.”

Eating just a half-ounce of walnuts or around one teaspoon of flaxseed oil is enough to meet these recommendations. Study authors say they would like to investigate the impact of ALA on other major chronic diseases in the future.

The study is published in Advances in Nutrition.

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