Yup'ik Eskimo Study
SEAFOOD.COM
NEWS [seafoodnews.com] - March 25, 2011 - A study of Yup'ik
Eskimos in Alaska, 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 such as diabetes and
heart disease.
The study, led by researchers
at Fred Hutchinson Cancer Research Center and conducted
in collaboration with the Center for Alaska Native Health
Research at the University of Alaska-Fairbanks, was published
online March 23 in the European Journal of Clinical Nutrition.
'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,' said lead author Zeina Makhoul, Ph.D.,
a postdoctoral researcher in the Cancer Prevention Program
of the Public Health Sciences Division at the Hutchinson
Center.
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.
Researchers analyzed data
from a community-based study of 330 people living in the
Yukon Kuskokwim Delta region of southwest Alaska, 70 percent
of whom were overweight or obese. As expected, the researchers
found that in participants with low blood levels of DHA
and EPA, obesity strongly increased both blood triglycerides
(a blood lipid abnormality) and C-reactive protein, or
CRP (a measure of overall body inflammation). Elevated
levels of triglycerides and CRP increase the risk of heart
disease and, possibly, diabetes.
'These results mimic those
found in populations living in the Lower 48 who have similarly
low blood levels of EPA and DHA,' said senior author Alan
Kristal, Dr. P.H., a member of the Hutchinson Center's
Public Health Sciences Division. 'However, the new finding
was that obesity did not increase these risk factors among
study participants with high blood levels of omega-3 fats,'
he said.
'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 said. 'It
appeared that high intakes of omega-3-rich seafood protected
Yup'ik Eskios from some of the harmful effects of obesity.'
While Yup'ik Eskimos have
overweight/obesity levels similar to those in the U.S.
overall, their prevalence of type 2 diabetes is significantly
lower - 3.3 percent versus 7.7 percent.
'While genetic, lifestyle
and dietary factors may account for this difference,'
Makhoul said, '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.'
For the study, the participants
provided blood samples and health information via in-person
interviews and questionnaires. Diet was assessed by asking
participants what they ate in the past 24 hours and asking
them to keep a food log for three consecutive days. Height,
weight, percent body fat, blood pressure and physical
activity were also measured.
The median age of the participants
was 45 and slightly more than half were female. The women
were more likely than the men to be heavy, and body mass
index (height-to-weight ratio) for all increased with
age.
'Residents of Yup'ik villages
joined this research because they were interested in their
communities' health and were particularly concerned about
the health effects of moving away from their traditional
ways and adopting lifestyle patterns similar to those
of residents in the lower 48 states,' Makhoul said.
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 that 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.
'If the results of such
a trial were positive, it would strongly suggest that
omega-3 fats could help prevent obesity-related diseases
such as heart disease and diabetes,' she said.
|
