A new study published in Prostaglandins, Leukotrienes, and Essential Fatty Acids shows that people likely need to eat more fish and take an omega-3 supplement to reach a cardioprotective Omega-3 Index level of 8 percent or higher.

The goal of this study was to answer the question: “What combination of (non-fried) fish intake and omega-3 supplement use is associated with a cardioprotective Omega-3 Index level (i.e., 8 percent or above)?” according to lead researcher Kristina Harris Jackson, a registered dietician who has a doctorate in nutritional sciences. Jackson is a research associate with OmegaQuant, a laboratory dedicated to “advancing the science and use of omega-3 fatty acids to improve health.” She also is the daughter of Bill Harris, the founder of OmegaQuant and the inventor of the Omega-3 Index.  

In 2018, the American Heart Association (AHA) updated its 2002 recommendations regarding fish and seafood consumption to “...1 to 2 seafood meals per week” from “...a variety of (preferably oily) fish at least twice a week.”

“This apparent downgrade in the recommendation (i.e., removal of ‘preferably oily’ and ‘at least’) was made despite evidence that consuming fish more frequently (such as daily or multiple times per day) may impart even greater cardioprotection,” Jackson said. “Further, an online commentary by Louis Kuller, M.D. (University of Pittsburgh) that accompanied the publication of the new AHA guidelines argued that fish intake recommendations should not be one-size-fits-all, but instead be based on the amount needed to achieve cardioprotective blood omega-3 levels.”

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Dr. Kuller, who also has a doctorate in public health, wrote in that study, “It is unclear why one to two servings were selected. … The successful DASH diet recommended ½ serving per day or about three to four servings per week.”

For this new study, Jackson and her team evaluated blood levels of omega-3s EPA and DHA from almost 3,500 people, and asked questions about their fish and supplement intake.

Individuals reporting no fish intake and taking no omega-3 supplements had an average Omega-3 Index of about 4.1 percent, which reflects the average for most Americans and is considered “deficient.”

At the other extreme, the average Omega-3 Index of people who reported taking a supplement and eating three servings of fish a week was 8.1 percent, which is the level defined in the research as being “cardioprotective.”

Thus, Jackson and her colleagues believe an 8 percent Omega-3 Index is most likely to be found in people eating at least three non-fried fish meals per week and taking an omega-3 EPA/DHA supplement.

“The AHA currently recommends one to two fish meals per week and it does not recommend supplementation for the general population. In light of our findings, this regimen is unlikely to produce a cardioprotective Omega-3 Index of 8 percent,” Jackson said. “Having dietary recommendations that aim to achieve a target blood level would likely be more effective at reducing the risk for heart disease.”

In 2018, data from a pooling project of 10 cohort studies confirmed that individuals with an Omega-3 Index of 8 percent or higher were 35 percent less likely to die from cardiovascular disease compared with those having an Omega-3 Index below 4 percent. Additional research has shown that higher omega-3 blood levels are beneficially related to cognitive function and even overall longevity.

Source: OmegaQuant