Sunday, January 16, 2011

Fatty liver: 70% to 90% of people with obesity or diabetes develop fatty liver.



Related : Hepatitis C and Fatty Liver: Still unhappy bedfellows?
NAFLD/NASH Utilizing Ultrasound and Liver Biopsy
20% of American adults have some degree of fatty liver disease


Posted: Jan. 16, 2011
HARVARD MEDICAL SCHOOL ADVISER

QUESTION: My doctor told me I have fatty liver disease, but I don't even drink alcohol. She said that it could have to do with the excess weight I have put on and that it could eventually harm my heart. What can I do?

ANSWER: The diagnosis of fatty liver disease is more common than you may realize -- perhaps as many as 20% of American adults have some degree of the problem.

Fatty liver disease was once diagnosed mainly in people who drink alcohol excessively. But the current surge of fatty liver disease in people who do not abuse alcohol is because of the dual epidemics of obesity and diabetes. Some 70% to 90% of people with obesity or diabetes develop fatty liver.

The prevailing theory is that fatty liver gets started because of insulin resistance, which is a common consequence of obesity, particularly when excess fat builds up in the abdomen.

When people are insulin resistant, their muscle, fat and liver cells don't respond normally to insulin. This causes levels of the hormone -- and the blood sugar it normally ushers into cells -- to build up in the blood. Insulin resistance is a complicated metabolic state that also includes an increase in the amount of free fatty acids circulating in the blood.

Fatty liver disease occurs when some of those fat molecules accumulate inside liver cells. These cells can trigger inflammation in the liver and damage to surrounding liver tissue.

When alcohol is not the culprit, the condition is called NASH -- nonalcoholic steatohepatitis ("steato" for fat and "hepatitis" because the liver is inflamed).

NASH is often a relatively stable, low-grade condition that people live with for years, with few if any symptoms. But it can start a cascade of serious damage to the liver and attempts by the organ to regenerate itself that culminate in an abundance of scar tissue and impaired liver function -- a condition called cirrhosis. Cirrhosis is irreversible and can lead to total failure of the liver. It also is associated with an increased risk for developing liver cancer.

It's just a theory, but an article published in the New England Journal of Medicine late last year argued that the inflammation and other factors pumped out by a fat-afflicted liver promote the atherosclerotic process that damages arteries and makes blood more likely to clot. This combination can lead to heart attack or stroke.

Treatments for NASH include diabetes medications, cholesterol-lowering statin drugs, vitamin E and even fish oil. But there is not enough evidence yet to endorse them. This leaves weight loss as the only recommended treatment for most cases of fatty liver disease and NASH.

It's important to protect your vulnerable liver from alcohol and talk to your doctor about hepatitis vaccinations.

In many cases, weight loss seems to have a very direct effect: As people lose weight, the fatty liver becomes less fatty. Crash dieting is a bad idea, though, because rapid weight loss (losing 4 pounds a week or more) can wind up damaging the liver.

In addition to weight loss, doctors will often advise people with diabetes who have fatty liver disease or NASH to be vigilant about controlling their blood sugar levels.

Many parts of the body come to grief once people become obese or develop diabetes. It's not surprising that our livers do, too.



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