Print

Email story

Comment

Letter to the editor

Fatty liver can start an unhealthy trend

By TOM VALEO
Published July 27, 2004

In the documentary Super Size Me, Morgan Spurlock chronicles the 30 consecutive days he spent eating every meal only at McDonald's. Spurlock is in superb health at the beginning of his experiment, according to the three doctors he consults. His blood pressure is normal, his body fat is low, his blood contains low levels of bad cholesterol and fat, and his liver is working precisely as it should.

Two weeks later, Spurlock's cholesterol has skyrocketed, the triglycerides in his blood have risen to unhealthy levels, he feels exhausted and depressed, and he complains of mild erectile dysfunction.

Most alarming, however, is that his liver is filling up with fat. "Your liver is turning into pate," one of Spurlock's doctors says.

Spurlock was developing Non-Alcoholic Fatty Liver Disease, or NAFLD, which has become the most prevalent liver disease in the United States.

Not recognized until 1980, NAFLD affects up to 25 percent of the population. The result, doctors believe, of a diet loaded with sugar and fat. Approximately 90 percent of obese people may have a fatty liver, which makes them more susceptible to cirrhosis of the liver, a leading cause of liver failure.

Dr. Ariel Feldstein of the Mayo Clinic was the principal investigator in a study that blames fatty liver disease on high levels of fatty acids in the blood. As the liver removes them, these fatty acids trigger a protein reaction that causes inflammation and can lead to cell death or cirrhosis.

The liver also ends up converting excess amounts of sugar in the blood to fat, according to Dr. Thomas Soderman of the University of South Florida College of Medicine.

"Every cell needs sugar except the liver, which sucks it up," Soderman said. "The extra blood sugar then gets turned into fat."

Unfortunately, the liver cells tend to hang on to that fat, which is what damages them.

Fatty liver disease is closely linked to insulin resistance, a common consequence of aging made worse by obesity. Insulin resistance means the body's cells become insensitive to insulin, the hormone that enables cells to absorb glucose (sugar) and use it for energy. When cells become resistant to the effects of insulin, the pancreas starts to secrete even more.

"What causes most cases (of fatty liver disease) is chronic elevation of insulin levels," said Dr. Brent Tetri, a professor of internal medicine at St. Louis University and one of eight investigators in a study funded by the National Institutes of Health on the association between obesity and fatty liver disease. "Insulin is a signal to cells, and when cells become a little deaf to the signal, the pancreas makes more insulin to yell at the cells. Then the cells get it, but the liver suffers from these high insulin levels."

How do you know if you're developing a fatty liver?

You probably won't experience any symptoms until your liver already has been badly damaged, and by then, the fat may have disappeared in a process known as "burned-out cirrhosis."

"Cirrhosis seems to drive the fat out," said Soderman.

The best way to detect a fatty liver is through ultrasound, a CAT scan or an MRI, which is the best test for fatty liver, but the most expensive.

The most effective way to prevent and reverse fatty liver disease is through exercise and weight loss.

"It seems that exercise is more important than weight loss," said Tetri. "Exercise changes the way muscle responds to insulin. It makes muscle more responsive. I still stress weight loss, but I emphasize exercise much more."

Avoid foods that cause blood sugar levels to rise quickly. A rush of sugar into the blood forces the pancreas to pump out large quantities of insulin. Straight sugar is the worst offender, of course. In Super Size Me, Spurlock points out the vast amounts of sugar in McDonald's products. But other foods, such as white rice and white flour, break down into sugar much faster than whole grains and vegetables, which take longer to digest. Paradoxically, many low-fat foods may actually contribute to fatty liver because they substitute sugar for fat.

Still, it is possible to make healthy changes in diet and lifestyle to prevent developing fatty liver. Get plenty of exercise, eat a healthful diet and keep your weight normal. If you suspect that you might be insulin resistant despite these efforts, see your doctor. Medications are available to make your cells more sensitive to insulin.

- Tom Valeo is a freelance writer who reports on medical and health issues. Write to him c/o Seniority, the St. Petersburg Times, P.O. Box 1121, St. Petersburg, FL 33731 or e-mail features@sptimes.com

[Last modified July 23, 2004, 13:21:22]