Fatty liver disease

"As the nation gets heavier, our livers will get fatter."
---Chin Hee Kim, MD

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease AND it affects 20-30% of the US population per Drs. Kim and Younossi writing in the Cleveland Clinic Journal of Medicine(1). NAFLD can range from no big deal fat in liver through inflammation and liver cell damage (nonalcoholic steatohepatosis or NASH) to cirrhosis, liver cancer, or liver failure.

The standard, automated laboratory blood profile includes a panel of liver enzymes. These transaminases(2) which are involved in the production of amino acids are part of the biochemical equipment within liver cells. They are normally present in the bloodstream in small amounts, but disruption of liver cells causes their blood levels to rise. A case of hepatitis skyrockets transaminase levels into the 1,000s and beyond, but even very low level elevations found on lab screening are worthy of follow-up because they may indicate an ongoing, asymptomatic inflammatory liver process that can ultimately lead to cirrhosis and liver failure.

Often, elevated liver enzymes or liver function tests (LFTs) in overweight persons demonstrating signs of metabolic troubles (fat concentrated around the waistline, elevated blood pressure, elevated triglycerides, low HDL, or high blood sugar) are the first sign of NAFLD. This fatty liver business is usually asymptomatic and only noted on lab testing. In order to chase down the cause of abnormal LFTs, we next order tests to check for chronic hepatitis B or C infections, auto-immune liver disease, or metabolic diseases such as abnormally stored copper or iron in the liver. An ultrasound of the liver is fairly accurate in assessing the presence of fat in the liver.

Liver biopsy is the best way to determine if the fatty liver troubles are benign or carry a risk of progression from nonalcoholic steatohepatosis to scarring and permanent liver damage or failure. Once diagnosed, the best approach to treating fatty livers is the same strategy that improves overall health in overweight persons on the road to diabetes or heart disease. These include weight loss (including use of bariatric or gastric bypass procedures), trials of various drugs that promote insulin sensitivity such as metformin, Actos, or Avandia or drugs that lower triglycerides and raise HDL levels such as statins and gemfibrozil. Fatty livers are more sensitive to damage from regular alcohol intake.

If you tend to pack the pounds around your waistline, be sure to ask your doctor to test your liver enzymes.
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1) Kim, HK and Younossi, ZM. Nonalcoholic fatty liver disease: A manifestation of the metabolic syndrome. Cleveland Clinic Journal of Medicine. October, 2008, Vol 75, pp 721-728.
2) Aspartate transaminase (AST) and alanine transaminase (ALT) levels generally range up to 40 or so. In mild NAFLD, AST <> ALT.