A diet of Alaska salmon rich in Omega-3 fatty acids appears to protect Yup'ik people from diabetes and heart disease -- even when the individuals in question have become obese, according to a recent study that examined eating habits and health in the Yukon Kuskokwim Delta region.
Scientists found that Yup'ik people in general consume about 20 times more of the complex fish oils every year than do people in the Lower 48 states, a subsistence-driven cuisine that may actually shield them from many health problems blamed on obesity, junk food and inactivity.
Y-K residents show similar levels of obesity as the overall U.S. population, yet experience far lower prevalence of the adult-onset diabetes linked to poor diet and weight issues -- about 3.3 percent versus about 7.7 percent.
The findings underscore what Alaska nutritionists and Native health experts have long argued: Eating wild Alaska salmon along with other traditional foods is uniquely healthy and trumps outdated, often misunderstood dietary recommendations that people should limit their intake of fish.
In this instance, "it appeared that high intakes of Omega-3-rich seafood protected Yup'ik Eskimos from some of the harmful effects of obesity," said Zeina Makhoul, Ph.D., a postdoctoral researcher in the Cancer Prevention Program of the Public Health Sciences Division at the Hutchinson Center, in a story posted online.
"While genetic, lifestyle and dietary factors may account for this difference, it is reasonable to ask, based on our findings, whether the lower prevalence of diabetes in this population might be attributed, at least in part, to their high consumption of Omega-3-rich fish."
Alaska Native village elders supported diet studies
The study, published March 23 in the European Journal of Clinical Nutrition, took some of the data gathered over the past decade by the Center for Alaska Native Health Research and performed a new analysis led by researchers at the Fred Hutchinson Cancer Research Center. Makhoul, the lead author, was one of 11 collaborators from Fairbanks, Seattle and Davis, Calif.
Scientists at the Native health center at the University of Alaska Fairbanks began working closely with Yup'ik leaders in the early 2000s in a federally funded investigation of the relationships among traditional diet, obesity and diabetes.
With the support and consultation of village elders, the scientists tested and interviewed 1,003 adults and teenagers spread among 10 southwest Alaska communities between 2003 and 2006 in pursuit of a public health mystery: How were certain people who ate the high-fat diets of traditional subsistence foods able to remain so healthy despite being overweight?
"What we've found is that the prevalence of obesity among Yup'ik Eskimos is no different than other people. It's no different than Caucasians living a very Western lifestyle," center co-director Bert Boyer told the Fairbanks Daily News-Miner in 2007 in a story about early results.
"But the intriguing part, and the exciting part, is that the prevalence of Type II diabetes in Yup'ik Eskimos is very low. That really piqued our curiosity."
That kind of diabetes typically strikes adults as a result of poor diet and weight gain over many years, and is thought to be just one consequence of an obesity epidemic triggering devastating health problems across the country.
"It turns out Yup'ik Eskimos have among the lowest levels of metabolic syndrome (or risk of obesity-related diseases such as diabetes) of any group worldwide, yet they are as overweight as anyone else in America," Boyer told the News-Miner.
Something was different, and it didn't appear to be genetics.
"We think the uniqueness comes from the food they eat," Boyer said at the time.
"Yup'ik people in our study are metabolically healthy and that diet and life style provide a delicate combination of protective and risk factors," concluded one of their reports in 2007.
Wild foods the answer to America's obesity epidemic?
Traditional Alaska Native foods aren't lean. But scientists say the kind of polyunsaturated fat oozing out of a sizzling salmon filet or packed within a hunk of seal has very different impacts on human health than the saturated fat in beef, fried foods and pastries.
Could the answer lie in the biochemistry of wild food?
That people ought to eat a lot more salmon and other high-fat fish is now an official national recommendation, though that wasn't always the case. Alaska public health officials and national diet gurus sometimes clashed in the 2000s, with previous federal guidelines cautioning people against eating too much fish due to potential exposure to mercury, and Alaskan experts urging as much salmon as the plate might hold.
The debate has now swung conclusively in favor of finners and jumpers, according to a new Harvard study released last week.
"There is strong evidence that eating fish or taking fish oil is good for the heart and blood vessels," added recommendations by the Harvard School of Public Health. "An analysis of 20 studies involving hundreds of thousands of participants indicates that eating approximately one to two 3-ounce servings of fatty fish a week -- salmon, herring, mackerel, anchovies, or sardines -- reduces the risk of dying from heart disease by 36 percent."
In their follow-up work with Alaska's Yup'ik people, Makhoul and her team focused on the salmon angle, trying to dial in on the impact of ingesting all those Omega-3 fatty acids.
"Because Yup'ik Eskimos have a traditional diet that includes large amounts of fatty fish and have a prevalence of overweight or obesity that is similar to that of the general U.S. population, this offered a unique opportunity to study whether Omega-3 fats change the association between obesity and chronic disease risk," they wrote.
They took a closer look at 330 Y-K Delta residents, drawn from seven of the 10 original communities. Slightly more than half were female, with a median age of 45, and 70 percent were overweight or obese. The participants had answered questions about their diet, kept a food log, and underwent measurements and tests.
Among other things, the scientists compared their levels of triglycerides and indicators of inflammation with blood levels of the healthy fats found in fish like salmon, sardines and tuna -- docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA.
Among obese Yup'ik people who carried low levels of those two Omega-3 fatty acids, there was no difference from similarly overweight folk in the Lower 48. But load up their blood with fish fat, and something remarkable occurred. The incidence of diabetes and heart disease fell.
"Obesity did not increase these risk factors among study participants with high blood levels of Omega-3 fats," said senior author Alan Kristal, Dr. P.H., a member of the Hutchinson Center's Public Health Sciences Division.
"Interestingly, we found that obese persons with high blood levels of Omega-3 fats had triglyceride and CRP concentrations that did not differ from those of normal-weight persons," Makhoul concluded.
While the study suggests that overweight or obese people will definitely benefit by eating more salmon, more studies are needed before the scientists would become willing to recommend taking fish oil pills as nutritional supplements.
"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."
Contact Doug O'Harra at doug(at)alaskadispatch.com
Alaska Dispatch Publishing