SAN DIEGO—A growing body of research indicates that consuming foods with high omega-3 fatty acid content, such as seafood, nuts and legumes, benefits brain health and prevents the decline of cognitive function, according to new research presented at the Experimental Biology 2014 meeting. However, many Americans do not receive adequate intake of these crucial nutrients.

Although some research shows no relation between omega-3s and cognitive health, the importance of long-chain polyunsaturated fatty acids (PUFAs) to brain health has been demonstrated in multiple previous studies. To assess whether lower dietary intake of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexanoic acid (DHA) were risk factors for cognitive decline, a team of researchers led by Tammy Scott, Ph.D., a scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University, conducted a longitudinal, observational study using the Boston Puerto Rican Health Study cohort.

Participants went through a series of cognitive tests in order, such as memory tests using a list of words, an attention test to repeat lists of numbers forward and backward, and a test of organization and planning involving copying complex figures. To determine the participants’ intake of PUFAs, they were given a questionnaire. The results were determined by comparing baseline test numbers to a follow-up test given two years later.

The researchers found that the intake of omega-3 PUFAs in the study sample of 895 participants was low. The 2010 U.S. Dietary Guidelines recommended an intake of 8 ounces (or more) of seafood per week to ensure an adequate intake of the very long chain omega-3 fatty acids (EPA and DHA). This translates to about 1,750 mg of EPA and DHA per week, which averages to 250 mg per day. Scott’s group reported that only 27% of the participants in their study met or exceeded that recommendation. The major source of EPA and DHA in their diets appeared to be from canned tuna. Based on the scientists’ findings, being in the lowest four quintiles of EPA and DHA intake was predictive of cognitive decline over two years.

“While more research is needed to determine whether intake of fatty fish such as salmon, tuna and trout can help prevent against cognitive decline, our preliminary data support previous research showing that intake of these types of fish have health benefits," Scott said.