How Does Fat Kill Thee? Many Ways

[Guest guest]

Interesting, but scary article... Marilyn

>

> How Does Fat Kill Thee? Many Ways

> Associated Press

>

> Story location: http://www.wired.com/news/medtech/0,1286,63425,00.html

>

> 02:11 PM May. 11, 2004 PT

>

> Research into the biology of fat is turning up some surprising new

> insights about how obesity kills. The weight of the evidence: It's the

> toxic mischief of the flesh itself.

>

> Experts have realized for decades that large people die young, and the

> explanation long seemed obvious. Carrying around all those extra pounds

> must put a deadly strain on the heart and other organs.

>

>

> Obvious but wrong, it turns out. While the physical burden contributes

> to arthritis and sleep apnea, among other things, it is a minor hazard

> compared with the complex and insidious damage wrought by the oily,

> yellowish globs of fat that cover human bodies like never before.

>

> A series of recent discoveries suggests that all fat-storage cells

> churn out a stew of hormones and other chemical messengers that

> fine-tune the body's energy balance. But when spewed in vast amounts by

> cells swollen to capacity with fat, they assault many organs in ways

> that are bad for health.

>

> The exact details are still being worked out, but scientists say there

> is no doubt this flux of biological cross talk hastens death from heart

> disease, strokes, diabetes and cancer, diseases that are especially

> common among the obese.

>

> " When we look at fat tissue now, we see it's not just a passive depot

> of fat, " says Dr. Rudolph Leibel of Columbia University. " It's an

> active manufacturer of signals to other parts of the body. "

>

> The first real inkling that fat is more than just inert blubber was

> the discovery 10 years ago of the substance leptin. Scientists were

> amazed to find that this static-looking flesh helps maintain itself by

> producing a chemical that regulates appetite.

>

> Roughly 25 different signaling compounds -- with names like resistin

> and adiponectin -- are now known to be made by fat cells, Leibel

> estimates, and many more undoubtedly will be found.

>

> " There is an explosion of information about just what it is and what

> it does, " Dr. Spiegel, director of the National Institute of

> Diabetes and Digestive and Kidney Diseases, says of fat. " It is a

> tremendously dynamic organ. "

>

> Fat tissue is now recognized to be the body's biggest endocrine organ,

> and its sheer volume is impressive even in normal-size people. A trim

> woman is typically 30 percent fat, a man 15 percent. That is enough

> fuel to keep someone alive without eating for three months.

>

> The fat cell's main job is to store our excess calories as fat. When

> people grow obese, their fat cells swell with fat and can plump up to

> three times normal size. As very overweight people get fatter still,

> they may also layer on many more fat cells.

>

> The problem is the volume of chemicals these oversize cells churn out,

> says Dr. Bray of Louisiana State University. " The big cell

> secretes more of everything that it secreted when it was small. When

> you get more of these things, they are not good for you. "

>

> Many scientists are trying to learn exactly what these excess

> secretions do that is so harmful. The answers will help explain -- and

> perhaps offer solutions to -- the real tragedy of the obesity epidemic,

> its disastrous effect on health.

>

> Obesity is a huge and growing killer, in the United States just

> slightly behind smoking. Moderately obese people live two to five years

> less than normal-size folks. For the severely obese, the reduction in

> life span may be five to 10 years.

>

> By far the biggest single threat of obesity is heart disease. Someone

> with a body mass index over 30 has triple the usual risk. Scientists

> can visualize many ways that fat cells' chemical flood contributes to

> heart attacks, heart failure and cardiac arrest.

>

> For instance, it has long been known that weight increases blood

> pressure. Once doctors thought this was a matter of physics, the force

> needed to push blood through the many more yards of blood vessels that

> nourish the extra flesh.

>

> But now it is clear that fat can trigger high blood pressure by making

> blood vessels narrow in several chemical ways. For instance, it

> produces a substance called angiotensinogen that is a powerful

> constrictor. At the same time, it stimulates the sympathetic nerves to

> squeeze the circulatory system. And that may just be the beginning.

>

> " It's a very complicated system, and the more we learn about it, the

> more complicated it becomes, " says Dr. Xavier Pi-Sunyer, head of

> obesity research at St. Luke's Roosevelt Hospital Center in New York

> City.

>

> One of the clearest hazards of overfilled fat cells is their influence

> on the body's production and use of insulin, the hormone that instructs

> the muscle to burn energy and the fat cells to store it. Oversize fat

> cells blunt the insulin message, in part by leaking fat into the

> bloodstream. So the pancreas must compensate by making more insulin and

> other proteins.

>

> Scientists now understand that increasing insulin levels -- part of a

> condition called insulin resistance -- are particularly harmful. They

> can directly damage the walls of arteries and lead to clogging.

>

> That leaking fat may also infiltrate the heart muscle, contributing to

> congestive heart failure. Misplaced deposits of fat can also ruin the

> liver and have become the second-leading reason for liver transplants

> after hepatitis B.

>

> Fat cells churn out a variety of proteins that cause inflammation,

> too. These may be especially destructive to the gunky buildups in the

> arteries, causing them to burst and triggering heart attacks and

> strokes.

>

> These inflammatory proteins and other fat-driven chemicals, such as

> growth hormones, may also contribute to one of the less-appreciated

> consequences of obesity -- cancer.

>

> " There is now conclusive evidence that obesity causes some cancers and

> strong evidence that it contributes to a wide variety of others, " says

> Dr. Thun, epidemiology chief at the American Cancer Society.

>

> The cancer society estimates that staying trim could eliminate 90,000

> U.S. cancer deaths a year. Among the varieties most clearly linked to

> weight are cancer of the breast, uterus, colon, kidney, esophagus,

> pancreas and gallbladder.

>

> The best evidence of how obesity causes malignancy is in breast cancer

> in older women. When the ovaries shut down after menopause, fat tissue

> becomes the primary producer of estrogen, which in turn can fuel the

> growth of breast tumors.

>

> The heavier women are when diagnosed with breast cancer, the more

> likely they are to die from the disease, says Dr. Holmes of

> Boston's Brigham and Women's Hospital. " Presumably it's because their

> cancers are dependent on estrogen, and heavier women have more

> estrogen. "

>

> Still, big-ticket killers like heart disease and cancer only start the

> long list of obesity's health ills. Among other things, obese people

> are more prone to depression, gallstones, even dying when in car

> accidents.

>

> Says Dr. Jensen of the Mayo Clinic, " There are so many ways

> that obesity can kill you. "

>

>