Microbiome - Human Nutrition Research Center on Aging - Tufts ...

Quieting a Gene
in Mice Helps Them
Resist Rich Food
f candy and potato chips didn’t
beckon from every street corner,
wouldn’t we all be thin?
Thankfully, science is looking
at ways to resist. <strong>Research</strong>ers
have found that silencing a particular
gene in mice keeps them
from getting fat, even when
presented with an abundance of
calorie-dense food.
Along with colleagues,
Andrew Greenberg, M.D., the
Atkins Professor in <strong>Nutrition</strong>
and Metabolism at Tufts School
of Medicine and director of
the Obesity and Metabolism
Laboratory at the HNRCA,
bred a strain of mice born
without the gene that codes for
perilipin-2, a protein that regulates
the storage of fat within
cells. They offered those mice,
along with a genetically conventional
group, the equivalent
of a Western diet—sugary,
high-fat food—and let them eat
their fill.
After 12 weeks, the mice
lacking perilipin-2 had gained
significantly less weight than
the control group, which, as
expected, continued to eat
hungrily. The perilipin-2-free
mice ate less in comparison,
and even moved around more.
They also had all the health
advantages that go along with
being lean: smaller fat cells, less
inflammation, lower triglyceride
levels and better insulin
sensitivity.
In addition to eating less
and moving more, the genetically
altered mice appeared
to have more brown fat cells,
which, unlike typical white fat
cells, actually have the ability
to burn calories.
Because humans also carry
the perilipin genes, the findings
eventually could lead to ways
to fight obesity and diabetes.
“This is an exciting observation
because it provides an opportunity
to identify new pathways
that modulate food intake,
physical activity and potentially,
metabolism of fat,” says
Greenberg, an associate professor
at the Friedman School.
The study was published in
the Journal of Lipid <strong>Research</strong>.
BIG CALORIES FROM
SMALL RESTAURANTS
Apologies, Cheesecake Factory. It turns out
you and the other big chain restaurants aren’t
the only ones who have been helping America
pack on the pounds.
HNRCA researchers found independent and
small-chain restaurants ply us with slightly
more calories on average than their equivalents
at national chains, and far more than we need.
The researchers analyzed 157 meals from
33 Mexican, American, Chinese, Italian,
Japanese, Thai, Indian, Greek and Vietnamese
restaurants in the Boston area. Not only did
the meals, which averaged 1,327 calories,
provide two-thirds of a person’s typical daily
calorie requirements, but a subset they looked
at were 6 percent more caloric than the national
chain meals.
Lorien Urban, Ph.D., N09, N11, a postdoctoral
scholar in the HNRCA Energy Metabolism
Laboratory and the first author, points out that
independent eateries, which make up half of
U.S. restaurants, are not subject to new federal
regulations that mandate that they post
calorie content information.
“Our findings suggest that routine reporting
of meal calorie content by all restaurants,
not just large chains, would encourage individuals
to make informed choices about their
diet and would discourage restaurants from
offering unhealthy portions,” she says.
ILLUSTRATIONS: ISTOCK PHOTO, MELINDA BECK (TOP)
summer 2013 tufts nutrition 5