Just how much eating fish is good for you has been a question of debate for some time, and now a new study adds some more data to the pile.
Older adults who have high blood levels of omega-3 fatty acids — as found in fatty seafood — “may be able to lower their overall mortality risk by as much as 27 percent and their mortality risk from heart disease by about 35 percent,” according to a Harvard Gazette account of a new study from Harvard School of Public Health (HSPH) and the University of Washington.
“Researchers found that older adults who had the highest blood levels of the fatty acids lived, on average, 2.2 years longer than those with lower levels,” reported the paper.
“Although eating fish has long been considered part of a healthy diet, few studies have assessed blood omega-3 levels and total deaths in older adults,” lead author Dariush Mozaffarian, associate professor in the Department of Epidemiology at HSPH, told the Gazette. “Our findings support the importance of adequate blood omega-3 levels for cardiovascular health, and suggest that later in life these benefits could actually extend the years of remaining life.”
The study was the first to compare blood biomarkers of fish intake to total mortality and specific causes of mortality. It was published online this week in Annals of Internal Medicine.
Ocean Views has reached out to Mozaffarian for comment, and will update this post if we connect with him.
In the meantime, we checked in with National Geographic Fellow Barton Seaver, a chef who is working on improving the sustainability of the choices we make, especially when it comes to seafood.
“The fact that eating seafood has been significantly linked to a longer lifespan and not just the absence of disease is a big deal,” Seaver said.
Seaver pointed to National Geographic’s just-updated Seafood Decision Guide as a tool that can help people find the best fish for them. Users can filter based on the mercury content of fish, omega-3 content, or choose special options like the choices for pregnant or nursing mothers.
“If people are living a little longer, don’t they also want a good planet?” Seaver asked.
For those who don’t want to eat any fish, for taste or ethical reasons, there may be another way to get some omega-3s, suggested National Geographic Explorer-in-Residence Sylvia Earle. She recently pointed out that fish pick up omega-3s from plant material they eat, so it should be possible for people to start going to the original source (people may have to re-learn to enjoy the finer tastes of seaweeds.)
Drilling Down on Results
The researchers analyzed 16 years worth of data from 2,700 Americans aged 65 and older. They concluded, according to the Harvard Gazette:
The researchers analyzed the total proportion of blood omega-3 fatty acids, including three specific ones, in participants’ blood samples at baseline. After adjusting for demographic, cardiovascular, lifestyle, and dietary factors, they found that the three fatty acids — both individually and combined — were associated with a significantly lower risk of mortality. One type in particular, docosahexaenoic acid, or DHA, was most strongly related to lower risk of death from coronary heart disease (CHD) (40 percent lower risk), especially CHD death due to arrhythmia (an electrical disturbance of the heart rhythm) (45 percent lower risk). Of the other blood fatty acids measured, eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA), DPA was most strongly associated with a lower risk of stroke death, and EPA most strongly linked to a lower risk of nonfatal heart attack. None of these fatty acids were strongly related to other, non-cardiovascular causes of death.
Overall, the study participants with the highest levels of all three types of fatty acids had a 27 percent lower risk of total mortality due to all causes.