That's the short version of three new studies from September's edition of The American Journal of Clinical Nutrition.
The studies focused on older adults and omega-3 fatty acids, which the body needs to be healthy and can only get from food (such as salmon, herring, walnuts, and flaxseeds) or supplements.
Though the three new studies all focus on older adults, omega-3 fatty acids are important for people of all ages. The new studies "underscore the potential importance of maintaining high dietary omega-3 fatty acid intakes throughout life," states an editorial published with the studies.
Omega-3s and Better Survival
Having high blood levels of the omega-3 fatty acid EPA, which is found mainly in fish but not in plants, may help longevity, one of the new studies shows.
The study took place in Norway. The researchers measured omega-3 fatty acid blood levels in 254 frail, elderly people (average age: 82) admitted to a Norwegian hospital.
Over the next three years, the patients with high blood levels of EPA were less likely to die than those with low levels of EPA.
That finding may stem from EPA's heart-healthy benefits, since heart disease was to blame for most patient deaths. Other omega-3 fatty acids -- and omega-6 fatty acids, which are more common than omega-3s in the typical American diet -- didn't affect the results.
Less Dementia With Omega-3s
In the second study, people with high blood levels of EPA were less likely to develop dementia.
The study comes from France, where researchers tracked new cases of dementia over four years among some 1,200 people aged 65 and older.
When the study began, participants provided blood samples. During the study, people with higher EPA blood levels were less likely to develop dementia. And people who ate fish regularly were less likely to develop dementia during the study.
Better Mood? Maybe Not
The third study, done in the Netherlands, showed no mood improvement from taking omega-3 supplements in healthy older adults.
The study included 302 people aged 65 and older who weren't depressed. For 26 weeks, they either took a high dose of EPA and DHA (another omega-3 fatty acid found in fish but not in plants), a lower dose of EPA and DHA, or a placebo. They didn't know what type of pill they were taking.
Before-and-after scores on depression surveys showed no mood-boosting perks for the omega-3 supplements. But that may be because participants didn't have depression to begin with, or because the surveys weren't designed to capture mood improvements in people without depression.