Higher levels of certain omega-3 fatty acids in the bloodstream were linked to a lower risk of death from a variety of causes, according to a new analysis published in the journal Nature Communications.
The researchers noted that there is some controversy surrounding the health effects of omega-3 fatty acids, which are found in high levels in a variety of seafood and plant foods. Many past studies have found health benefits linked to consuming omega-3s, including in the area of heart health. There is also evidence that they may help improve insulin sensitivity, which could be especially beneficial for people with type 2 diabetes. But other studies have found only a weak link between a higher omega-3 intake and health outcomes.
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For the latest analysis, the researchers looked at the relationship between blood levels of omega-3s and health outcomes — with a focus on the risk of death — in 17 different studies. Looking at blood levels of omega-3s — rather than trying to figure out how much of these fats people consume based on dietary surveys — has the benefits of being more precise and of examining the biological effects of these fats in a more direct way, since eating the same amount of omega-3s won’t lead to the same blood levels in every person. The studies included 42,466 people who were followed for a median period of 16 years, during which 15,720 participants died.
Long-chain omega-3s linked to lower death risk
After controlling for relevant risk factors that were known to affect the risk of death from various causes, the researchers found that participants who ate the highest levels of long-chain omega-3s (those with a carbon chain of 20 to 22) — the top 20% of participants — were 15% to 18% less likely to die during the study period than people in the bottom 20% for long-chain omega-3 consumption. Long-chain omega-3s — known by the abbreviations for their chemical names EPA, DPA, and DHA — are found mostly in fatty fish and other seafoods. The researchers also found a similar risk reduction for death caused specifically by cardiovascular disease, cancer, and other causes.
But when the researchers looked at intake of a shorter-chain omega-3 (ALA, with an 18-carbon chain) found in plant foods, they found no relationship between consumption levels and the risk of death. These results suggest that plant sources of omega-3s in the form of ALA — such as flaxseed, walnuts, and canola oil — may not offer the same health benefits as seafood sources of EPA, DPA, and DHA.
Want to learn more about omega-3 fats? Read “Are Omega-3 Fats Good for Diabetes?”
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