• serum levels of aminotransferases [ Time Frame: months 12 and 24 ] [ Designated as safety issue: Yes ]
  

• Liver histology (inflammation and fibrosis) [ Time Frame: month 24 ] [ Designated as safety issue: No ]
  

InChildren or adolescents with well-characterized and liver biopsy confirmed NAFLD will be enrolled. They will be randomized to treatment with alpha tocopherol 600 IU/d plus ascorbic acid 500 mg/d (n=45) or an identical placebo (n=45) given orally. All patients will be included in a lifestyle intervention program consisting of a diet tailored on the individual requirements and physical exercise. The body mass index (BMI) and BMI Z-score will be calculated . Obesity was defined for a percentile of BMI ≥ 95th percentile for age and gender .

Patients will undergo a medical evaluation every three months during the 24-month study period. Laboratory tests including liver enzymes and lipids will be repeated at 3-month intervals during the 24-month study duration.

Ultrasonography of the liver will be repeated at the end of the study period.

Evaluation of Glucose Metabolism and Insulin Sensitivity A 2-hour oral glucose tolerance test (OGTT) will be performed at baseline and repeated at 24 mo. of treatment with the standard 1.75 g of glucose per kg, or maximum of 75 g. Glucose tolerance status will be determined according to the classification of the American Diabetes Association in which fasting plasma glucose (FPG) levels up to 99 mg/dl are considered normal; impaired fasting glucose (IFG) is defined by a FPG of 100-125 mg/dl; impaired glucose tolerance (IGT) is defined by a 2-hour plasma glucose of 140-199 mg/dl; diabetes mellitus is defined by a FPG ≥126 mg/dl, or a 2-hour plasma glucose ≥200 mg/dl . The degrees of insulin resistance and sensitivity will be determined, respectively, by the homeostatic model assessment (HOMA-IR) using the formula: IR = (insulin*glucose)/22.5; and by the insulin sensitivity index (ISI) derived from OGTT using the formula: ISI = (10,000/square root of [fasting glucose x fasting insulin] x [mean glucose x mean insulin during OGTT]).

Liver biopsy Liver biopsy will be performed at baseline and repeated at 24 mo. of treatment. Biopsies will be routinely processed and analyzed as described previously. Pre- and post-treatment liver biopsies will be reviewed and scored by a single pathologist who will be unaware of the assigned treatment, patients' clinical and laboratory data, and liver biopsy sequence. The main histological features of NAFLD including steatosis (macro and microvesicular), inflammation (portal and lobular), hepatocyte ballooning, and fibrosis will be scored using the scoring system for NAFLD recently proposed by the NIH-sponsored NASH Clinical Research Network.