Fats in Liver Can Lead to More Health Risks
WASHINGTON - For years, scientists have warned people that having an apple-shaped figure or a beer belly is a health risk.
They said people with wide girths are more likely to have visceral or intra-abdominal fat, which increases their risk of diabetes, heart disease, stroke and some types of cancer.
But new research, presented Sunday at the annual meeting of the Obesity Society, shows that belly fat may not be the biggest bad guy behind some of the medical issues. "Fat in the liver is a more important indicator of health problems," says Samuel Klein, director of the Center for Human Nutrition at Washington University School of Medicine in St. Louis.
Klein and colleagues recruited 31 obese men and women and looked at their visceral fat, which surrounds the organs in the belly, and their liver fat. Some people had high amounts of liver fat; others had normal amounts. A normal liver contains 5 percent fat or less, but a severe fatty liver may contain up to 50 percent, Klein says. The latter is referred to as non-alcoholic fatty liver disease.
Using several different medical tests, the researchers found that people with fatty livers:
- Make more triglycerides, which are released from the liver into their bloodstream and can increase the risk of heart disease.
- Are more likely to be resistant to the action of their own insulin, meaning their bodies don't regulate blood sugar properly, which can lead to type 2 diabetes, Klein says. Over time, high sugar levels damage large and small blood vessels, leading to heart disease, stroke, nerve damage, amputations, blindness and kidney disease.
"We do not yet know whether the liver fat is causing these health problems or is simply a very good indicator of health risk," he says. "Even though it looks like visceral fat itself might not cause harm, it is often high in people with increased liver fat."
About 30 percent of adults and a third of overweight children and adolescents have too much liver fat, he says. If you are obese, 30 or more pounds over a healthy weight, you are at a higher risk of having non-alcoholic fatty liver disease.
The bottom line: If you're too heavy, it's a good idea trim down, he says. A weight loss of as little as 2 percent to 5 percent can cause a marked reduction in liver fat.
In a related study, Elisa Fabbrini of Washington University School of Medicine found that severely obese people who lost weight after gastric bypass surgery significantly lowered the fat in the liver.