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Study finds Asians more at risk from
abdominal fat
Concentration greater than Caucasians with
similar body types A new study by B.C. scientists suggests being
overweight is particularly dangerous for those of Chinese and South Asian
descent -- who, the study found, actually accumulate fat differently than
Caucasians.
Researchers measured the body fat of more
than 800 volunteers in Greater Vancouver of various ethnic backgrounds.
What they found is that, for the same amount
of total body fat, Chinese and South Asian people had a far greater
concentration of fat in their inner abdomen -- where it poses the greatest risk
for diabetes and heart disease.
For example, the study found that a
moderately overweight Chinese person has, on average, 36 per cent more
inner-abdominal fat than a Caucasian person of the same size. And a South Asian
of average weight has 23 per cent more inner-abdominal fat than someone
Caucasian.
Aboriginals showed no difference from
Caucasians.
Scott Lear, professor of kinesiology at Simon
Fraser University who led the study, said the ethnic gap is so profound that it
may be necessary to redefine what obesity means for Asians.
At the moment, regardless of ethnic
background, you are considered at risk of health problems if you have a waist
circumference larger than 102 centimetres (40 inches) for men or 88 centimetres
(35 inches) for women.
Given the added health risks weight seems to
pose for Asians, said Lear, it may make sense to create new, ethnic-specific
weight standards for them -- such as 90 centimetres (35 inches) for men and 80
centimetres (32 inches) for women.
Lear said the definition of overweight under
the Body Mass Index -- a calculation based on height and weight -- may also need
to change for Asians, dropping from 25 to 23.
"We're in the process of coming up with
some guidance for what the [new] targets should be," he said.
Lear doesn't know why Asians accumulate fat
differently.
But the ethnic gap persists even after
controlling for things like diet, height and level of exercise -- suggesting it
has something to do with genetics.
One theory, said Lear, is that Asia underwent
more famines than Europe -- causing its people to evolve the ability to store
fat more easily.
In recent years, scientists have discovered
that overall weight is far less important for good health than where that weight
is distributed -- with abdominal, or belly, fat most closely linked with heart
disease and diabetes.
And while most people focus on subcutaneous
fat -- the belly fat they can pinch under their skin -- it is actually the
abdominal fat deep within the body that is the most dangerous.
It is this fat that Lear's team studied by
taking CT scans of people's bellies.
Exactly why inner-abdominal fat is so
unhealthy is not known, though it may be that it puts greater stress on the
liver.
Rema Sanghera, a dietitian at BC Women's
Hospital, works with pregnant women from various ethnic backgrounds to reduce
their risk of diabetes.
"Our hope is that, since mom is the
chief cook in the family, that changes she makes will have a trickle-down effect
for other family members as well," she said.
Sanghera said the incidence of diabetes among
South Asians is several times that of the general population.
She said she hopes Lear's study results in
new guidelines for health workers like herself -- so they can do a better job of
identifying unhealthy weight in Asians.
Lear's study was published in the current
edition of the American Journal of Clinical Nutrition. -
by Chad Skelton VANCOUVER
SUN 2007 August 23
Tight abs equal long life
Tight abs do more than just make you look good
on the beach. A new study says they could help you live longer, too.
People with low levels of stomach muscle strength and
endurance tend to die earlier, researchers concluded after tracking thousands of
Canadians who participated in a national fitness survey.
Oddly, the scientists reported that muscles associated
with performing push-ups do not extend one's lifespan.
While it is common knowledge that aerobic fitness
increases longevity, the new research provides hard evidence of something
exercise experts have long suspected -- muscular strength can also add years to
your life.
"Yes, it is important to maintain aerobic
physical activities, for sure," said Dr. Peter Katzmarzyk, co-author of the
study.
"But we also can't ignore the muscular strength,
endurance, flexibility aspects of it. We need to be incorporating these into our
lifestyles, particularly as we get older."
The benefits of strong abdominal muscles tend to flow
to those in the top 25% of the population in terms of abdominal strength, he
said.
Dr. Katzmarzyk is with York University's school of
kinesiology and health science in Toronto; his co-author, Dr. Cora Craig, is
with the Canadian Fitness and Lifestyle and Research Institute in Ottawa.
Their paper, published this month in the U.S.-based
journal Medicine and Science in Sports and Exercise, says it is not completely
clear why strong stomach muscles stave off death, but they do have some
theories.
One is that maintaining adequate strength and
endurance is important to keeping mobile and independent as people age.
Another is that muscles are a significant site for the
deposit of glucose. In other words, Dr. Katzmarzyk said, more muscles and less
fat tend to protect people from type 2 diabetes, hypertension and other
metabolic diseases.
Yet neither of those theories explains why strong
stomach muscles, but not other muscle groups, would extend life.
The researchers tracked 8,116 men and women, aged 20
to 69, who participated in the 1981 Canada Fitness Survey. Among other things,
the survey tested strength by examining abilities to perform sit-ups and
push-ups, as well as measuring grip strength.
The results were correlated to 238 deaths that
occurred in the subsequent 12 years. The major causes of death were cancer, at
39%, and cardiovascular disease, at 26%.
After filtering out other health-related factors such
as aerobic fitness, the study found men and women with low levels of abdominal
strength, as indicated by their sit-up performance, were significantly more
likely to have died than others.
The authors wondered whether the link between
abdominal strength and death had more to do with people's waist size, which has
long been identified as an important health factor. But when they reworked the
data to remove waist circumference as an issue, they obtained the same results.
The study also discovered that trunk flexibility had
little effect on mortality rates. That suggests flexibility might be related
more to maintaining quality of life and independent living in the elderly than
in preventing early death, the paper said. - by
Tom Blackwell National
Post 14 May 2002
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