A diet loaded with salmon may help keep some diseases at bay

Fish-rich diet linked to reduction in markers of chronic disease risk among overweight Yup’ik Eskimos

Think of it as delicious disease protection

By Colleen Steelquist, Hutchinson Center Science Editor

The Yukon–Kuskokwim Delta is one of the largest river deltas in the world, about the size of Oregon. Located where Alaska’s two largest rivers empty into the Bering Sea on the state’s west coast, it’s home to Yu’pik Eskimos.

Most of these Alaska Natives subsist by hunting, fishing and gathering, the way their ancestors did before them. The area has virtually no roads; travel is by bush planes, boats or snowmobiles.

Come spring and summer, it’s salmon time in the delta. A time when bears get fat and fishermen don’t sleep. And it’s also a time to indulge my taste buds with a succulent, buttery slab of roasted salmon.

For me, wild salmon is always a treat. For the people of rural Alaska, it’s a way of life. The warmer months are spent catching, cleaning, smoking, freezing and canning salmon. And, it turns out, that protein mainstay is keeping obesity related diseases at bay for the Yup’ik Eskimos.

A recent study of the Yup’ik Eskimos, who on average consume 20 times more omega-3 fats from fish than people in the lower 48 states, suggests that a high intake of these fats helps prevent obesity-related chronic diseases like diabetes and heart disease.

Paula Ayunerak and Cecilia Tucker of the Yukon-Kuskokwim Delta region of Alaska clean fresh-caught salmon at their fish camp. Photo courtesy of Gunnar Ebbesson

Hutchinson Center researchers Drs. Zeina Makhoul and Alan Kristal collaborated with colleagues at the Center for Alaska Native Health Research at the University of Alaska-Fairbanks, on the study.

Similar to the general U.S. population, 70 percent of the Yup’ik Eskimos studied were overweight or obese. Their fish-loaded traditional diet offered a unique opportunity to study whether omega-3 fats change the association between obesity and chronic disease risk.

The fats the researchers were interested in measuring were those found in salmon, sardines and other fatty fish: docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA.

The researchers found obese participants with low blood levels of DHA and EPA had elevated levels of two blood markers linked to increased risk of heart disease and possibly diabetes, much like the rest of the U.S. population.

But overweight and obese Yup’ik Eskimos who had high levels of omega-3 fats, thanks to their fish consumption, did not have those risk factors.

“It appeared that high intakes of omega-3-rich seafood protected Yup’ik Eskimos from some of the harmful effects of obesity,” Makhoul said.

Indeed, the prevalence of type 2 diabetes is significantly lower—3.3 percent versus 7.7 percent—in the Yup’ik Eskimos than in the U.S. population overall.

The researchers said that while genetic, lifestyle and dietary factors may account for the difference, it’s reasonable to attribute the lower prevalence of diabetes in this population, at least in part, to their high consumption of omega-3-rich fish.

Based on these findings, should overweight and obese people concerned about their chronic disease risk start popping fish oil supplements or eat more fatty fish?

“There are good reasons to increase intake of fatty fish, such as the well-established association of fish intake with reduced heart disease risk,” Makhoul said. “But we have learned from many other studies that nutritional supplementation at very high doses is more often harmful than helpful.”

Before making a public health recommendation, the researchers said a randomized clinical trial is needed to test whether increasing omega-3 fat intake significantly reduces the effects of obesity on inflammation and blood triglycerides.

Until that study happens, it certainly couldn’t hurt to enjoy salmon more often—or other heart-healthy sources of omega-3 fats like halibut, avocados and walnuts. Hungry yet?