When it comes to the benefits of a food or nutrient (or even a drug), one of the best indications of efficacy is a reduced risk of death. This makes sense, of course—if a food or nutrient helps us live longer, that’s a good thing. A recent study published in the Annals of Internal Medicine investigated the connection between increased omega-3 levels in the blood and risk of death.

The researchers found that increased omega-3 levels may be able to lower the risk of death from all causes by up to 27 percent—and may lower the risk of death from heart disease by up to 35 percent. That’s good news, of course, and not at all surprising to me, given the vast body of research validating the health benefits of this important nutrient.

This study is important because they looked at actual blood levels of omega-3, and not just dietary intake. I do wonder why they chose plasma levels of omega-3 over the red blood cell membrane levels (which are considered the best marker of long-term omega-3 intake). At any rate, assessing omega-3 levels should be a part of any omega-3 study, and these researchers recognize that.

The researchers measured levels of certain omega-3 fatty acids found in fish: DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid), and DPA (docosapentaenoic acid). DHA and EPA are the two omega-3s most known for their beneficial effects on health. The study found that increased DHA levels was strongly related to a reduced risk of heart disease health, especially due to heart arrhythmias, or irregular heartbeats. Increased EPA and DPA were strongly related to lower risk of stroke death and EPA levels associated with lower risk of nonfatal heart attack.

To increase your omega-3 levels, eat fish high in omega-3 fats, yet low in mercury (sardines, salmon, and herring are great choices), and supplement with a high-quality, purified fish oil.