Eating fish could slash an older person's risk of dying prematurely by more than a quarter, and their risk of dying from heart disease by more than a third, a new study from the Harvard School of Public Health and the University of Washington has found.
Indeed researchers discovered that older adults with the highest blood levels of the fatty acids found in fish lived, on average, 2.2 years longer than those with lower levels.
"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," said lead author Dariush Mozaffarian, associate professor in the Department of Epidemiology at Harvard, in a press release. "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."
Researchers have long linked the consumption of unsaturated fats in fish with a reduced risk of dying from heart disease. And the American Heart Association recommends eating fish -- especially fatty fish -- at least twice a week.
But this is the first time researchers have linked levels of fish consumption with death rates.
In their study, researchers examined 16 years of data pertaining to 2,700 healthy U.S. adults aged 65 or older who participated in the Cardiovascular Health Study (CHS). The researchers also analyzed the total proportion of blood omega-3 fatty acids -- including three specific ones -- in participants' blood samples at baseline. After adjusting for dietary, lifestyle and other factors, they found that the fatty acids were linked with a significantly lower risk of mortality.
One type in particular -- docosahexaenoic acid (DHA) -- was most strongly related to a 40 percent lower risk of coronary heart disease death. Of the other blood fatty acids measured -- eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) -- DPA was most strongly associated with lower risk of stroke death, and EPA most strongly linked with lower risk of nonfatal heart attack, according to a press release. None of these fatty acids were dramatically related to other, noncardiovascular causes of death.
Overall, 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.
When researchers examined how the consumption of omega-3 fatty acids related to blood levels, the greatest rise in blood levels occurred when going from a very low intake to about 400 mg per day. After that, blood levels rose much more gradually.
"The findings suggest that the biggest bang-for-your-buck is for going from no intake to modest intake, or about two servings of fatty fish per week," Mozaffarian said.
The study was published online April 1 in Annals of Internal Medicine.
The types of fish that contain high levels of omega-3 include mackerel, trout, tuna, salmon, herring, sardines and anchovies.