Abdominal fat and what to do about it
Though the term might sound dated, “middle-age spread” is
a greater concern than ever. As people go through their middle years,
their proportion of fat to body weight tends to increase — more
so in women than men. Extra pounds tend to park themselves around the
midsection
At one time, we might have accepted these changes as an inevitable fact
of aging. But we’ve now been put on notice that as our waistlines
grow, so do our health risks. Abdominal, or visceral, fat is of particular
concern because it’s a key player in a variety of health problems — much
more so than subcutaneous fat, the kind you can grasp with your hand.
Visceral fat, on the other hand, lies out of reach, deep within the abdominal
cavity, where it pads the spaces between our abdominal organs.
Visceral fat has been linked to metabolic disturbances and increased
risk for cardiovascular disease and type 2 diabetes. In women, it is
also associated with breast cancer and the need for gallbladder surgery.
Fat accumulated in the lower body (the pear shape) is subcutaneous,
while fat in the abdominal area (the apple shape) is largely visceral.
Where fat ends up is influenced by several factors, including heredity
and hormones. As the evidence against abdominal fat mounts, researchers
and clinicians are trying to measure it, correlate it with health risks,
and monitor changes that occur with age and overall weight gain or loss.
.
The good news is that visceral fat yields fairly easily to exercise
and diet, with benefits ranging from lower blood pressure to more favorable
cholesterol levels. Subcutaneous fat located at the waist — the
pinchable stuff — can be frustratingly difficult to budge, but
in normal-weight people, it’s generally not considered as much
of a health threat as visceral fat is.
Research suggests that fat cells — particularly abdominal fat
cells — are biologically active. It’s appropriate to think
of fat as an endocrine organ or gland, producing hormones and other substances
that can profoundly affect our health. Although scientists are still
deciphering the roles of individual hormones, it’s becoming clear
that excess body fat, especially abdominal fat, disrupts the normal balance
and functioning of these hormones.
Scientists are also learning that visceral fat pumps out immune system
chemicals called cytokines — for example, tumor necrosis factor
and interleukin-6 — that can increase the risk of cardiovascular
disease. These and other biochemicals are thought to have deleterious
effects on cells’ sensitivity to insulin, blood pressure, and
blood clotting.
One reason excess visceral fat is so harmful could be its location near
the portal vein, which carries blood from the intestinal area to the
liver. Substances released by visceral fat, including free fatty acids,
enter the portal vein and travel to the liver, where they can influence
the production of blood lipids. Visceral fat is directly linked with
higher total cholesterol and LDL (bad) cholesterol, lower HDL (good)
cholesterol, and insulin resistance.
Insulin resistance means that your body’s muscle and liver cells
don’t respond adequately to normal levels of insulin, the pancreatic
hormone that carries glucose into the body’s cells. Glucose levels
in the blood rise, heightening the risk for diabetes. Now for the good
news
So what can we do about tubby tummies? A lot, it turns out. The starting
point for bringing weight under control, in general, and combating abdominal
fat, in particular, is regular moderate-intensity physical activity — at
least 30 minutes per day (and perhaps up to 60 minutes per day) to control
weight. Strength training (exercising with weights) may also help fight
abdominal fat. Spot exercising, such as doing sit-ups, can tighten abdominal
muscles, but it won’t get at visceral fat.
Diet is also important. Pay attention to portion size, and emphasize
complex carbohydrates (fruits, vegetables, and whole grains) and lean
protein over simple carbohydrates such as white bread, refined-grain
pasta, and sugary drinks. Replacing saturated fats and trans fats with
polyunsaturated fats can also help.
Scientists hope to develop drug treatments that target abdominal fat.
For example, studies of the weight-loss medication sibutramine (Meridia),
have shown that the drug’s greatest effects are on visceral fat.
Rimonabant (Acomplia) — not yet FDA-approved — is the first
of a new class of drugs that block a receptor in the brain that increases
appetite. Acomplia has been shown to modestly reduce the accumulation
of fat at the waist.
For now, experts stress that lifestyle, especially exercise, is the
very best way to fight visceral fat.
February 2007 update
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