Non-alcoholic steatohepatitis (NASH), the most severe form of liver injury in the spectrum of non-alcoholic fatty liver disease (NAFLD), has emerged as the major cause of chronic liver disease in developed countries. Among adults in the United States, the prevalence is between 5.7% and 17%. These rates are expected to increase concurrent with the epidemics of obesity and type 2 diabetes mellitus, which are the major risk factors for NAFLD and NASH. In addition to its high prevalence, NASH is also a progressive fibrotic disease that advances to cirrhosis and liver related death in 20% and 12% of patients, respectively. Among NASH patients with cirrhosis, 40% have liver related death. Diabetics are particularly prone to experience these poor outcomes. No therapy has been proven effective for patients with NASH.

The purpose of this study is to find out whether treatment with polyunsaturated fatty acids (eicosapentaenoic acid [EPA] combined with docosahexaenoic acid [DHA] called Opti-EPA) improves NASH compared to treatment with placebo pills. The placebo pills will contain corn oil and will be contained in a capsule, but have no medical effect on the body. The investigators will determine improvement in NASH from microscopic changes in the subject's liver tissue during 48 weeks of treatment. This means that the subject will need to have a liver biopsy before and after the treatment.

Omega-3 fatty acids are a form of polyunsaturated fats, one of the four basic types of fat that the body gets from food. (Cholesterol, saturated fat, and monounsaturated fat are the others.) One's body does not make this type of fat; it comes from food sources. These fats are found in foods like cold water fish (tuna, salmon, and mackerel), and vegetable products like flaxseed oil and walnuts.

Research shows that polyunsaturated fats are good for people. Studies have shown that it is good for heart health by playing a role in keeping blood cholesterol levels low, keeping irregular heart rhythms stable, and reducing blood pressure.

The drug being studied, Opti-EPA, is a nutritional supplement. They do not have to be reviewed by the Food and Drug Administration (FDA) like medicines do. Opti-EPA is considered experimental in this study. This means that the United States Food and Drug Administration (FDA) has not approved it for use in people with nonalcoholic fatty liver disease.