Home' Trinidad and Tobago Guardian : October 3rd 2015 Contents A26
body & soul
Guardian www.guardian.co.tt Saturday, October 3, 2015
Nutritionists often praise the Mediterranean diet,
which is rich in nuts, olive oil, fish, fruits and veg-
etables. Scientists believe it s one of the world s
healthiest patterns of eating, and can protect against
a lot of chronic diseases.
In the Arctic, the typical meal looks very different.
There, a traditional plate would have some fatty
marine animal like seal or whale and not much else---
fruits and vegetables are hard to come by in the harsh
climate. And yet despite the fact that the high-fat
Arctic diet may sound like a heart attack waiting to
happen, the Inuit tend to have low rates of heart dis-
ease and diabetes.
Researchers thought maybe it was the omega-3
fatty acids in the meat and blubber that might be
protective. But a new study on Inuit in Greenland
suggests that Arctic peoples evolved certain genetic
adaptations that allow them to consume much higher
amounts of fat than most other people around the
world, according a team of researchers reporting
recently in the journal Science.
Computational biologist Rasmus Nielsen at the
University of California, Berkeley led the research,
and began by looking for genetic differences between
a 191 Inuit in Greenland, 60 Europeans, and 44 ethnic
"When we did that, it pointed directly to one group
of genes where we had an extremely strong signal,"
Nielsen says. "They regulate how much of these
omega-3s and omega-6s you make yourself naturally."
Nearly all of the Inuit in Nielsen s study had vari-
ances in these genes that researchers think slow down
the body s natural production of omega-3 and omega-
"We saw that the Inuit have such a high diet of
omega-3s, so they produce much less of it themselves,"
Nielsen says. And the genes seem to play a role in
lowering levels of LDL cholesterol, the bad kind that s
linked to heart disease. Only about three per cent of
Europeans and 15 per cent of Chinese had the same
genetic markers, the team writes.
Nielsen thinks these genes helped Inuit ancestors
survive in the brutal cold near the North Pole and
stay healthy on a diet of almost exclusively fat and
protein. And he thinks the genes are mostly unique
to humans living in this environment.
But there s a lot of uncertainty about the genes.
"The regulation of fats in your body is a really complex
network. You turn one knob, and it just changes
everything everywhere else," Nielsen says. So, he
notes, the full implication of having these mutations
still isn t well understood.
That s part of the reason why some researchers
aren t completely blown away by the study. Whether
or not these genes have helped Inuit stay slim on a
high-fat diet is still unclear, says Joel Hirschhorn, a
geneticist at Harvard Medical School. "They re taking
a leap of faith," he says.
The genes in question seem to influence so many
different processes in the body that pinpointing their
effect is difficult, he says. "It s harder to go beyond
the known biology of these genes and make con-
nections to weight."
On top of that, Hirschhorn thinks there could be
reasons other than diet for why Inuit have these
mutations. "There are lots of things about the lifestyle
in Greenland that are different and could lead to
these adaptations," he says.
Even so, Hirschhorn says he s excited about the
paper because "it s a clear example of human evo-
lution." Like the genes that have allowed groups that
practice dairying to tolerate lactose in milk, it s another
example of human adaptations to different environ-
ments or diets, says Sarah Tishkoff, a geneticist at
the University of Pennsylvania.
Nowadays, very few Greenlanders still eat a com-
pletely traditional diet. And the move away
from the high-fat, high-protein diet may be
leading to the rising rate of diabetes.
That suggests that understanding these
adaptations could eventually lead to specialised
diets for each person. "We know now that
the Inuit adapted to a very specific diet. That
may be true for other populations as well,"
he says. In other words---the answer to how
harmful a high-fat diet is for you could depend
on your genomics. (www.npr.org)
Secret to the Inuit high-fat
diet may be good genes
ate two fresh
seals that hunters
skinned at a 2009
Celebration of the
Seal event to
assert Inuit pride.
are fatty, it seems
the Inuit genes
adapted to an
diet to maintain
health in that
PHOTO: JIM BELL
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