מאמר שהתפרסם לאחרונה
Vitamins E and C Beneficial in Fatty Liver Disease Supplementing with vitamins E and C may improve liver fibrosis in people with nonalcoholic steatohepatitis (NASH), according to a new study in The American Journal of Gastroenterology (2003;98:2485–90). NASH is an advanced form of a group of conditions collectively referred to as nonalcoholic fatty liver disease. Nonalcoholic fatty liver disease is usually not life threatening; however, in some cases the NASH form may lead to the progressive formation of abnormal fibrous tissue in the liver (fibrosis), eventually culminating in generally irreversible liver damage (cirrhosis of the liver), liver failure, or liver cancer. NASH is often associated with obesity, high blood levels of fats (called lipids), diabetes, and high blood pressure. Although the disease process is not completely understood, some factors are thought to contribute to the development of NASH. These include insulin resistance (the reduced ability of the body to respond to circulating levels of insulin); free-radical damage to fatty acids in the body, leading to inflammation and eventual tissue death and liver fibrosis; and dietary habits that cause blood fats to accumulate in the liver. Since there is no cure for NASH, most treatment plans are aimed at reducing the risk factors. Current recommendations may include lipid regulation (reduction of blood fats by dietary changes, nutritional supplementation, or lipid-lowering medications), gradual weight loss, insulin sensitizers (agents that enhance the body’s response to insulin), and supplementation with antioxidants. New drugs are also being investigated. This study was designed to determine the response of various parameters of liver health in people with NASH when treated with the antioxidant vitamins E and C. Specifically, liver inflammation and tissue death (necrosis), liver fibrosis, and liver enzymes (a measure of liver inflammation) were assessed. People with a diagnosis of NASH were randomly assigned to take either (1) vitamin E (1,000 IU) and vitamin C (1,000 mg) or (2) placebo every day for six months. Both groups were encouraged to follow a weight-loss program and to consume less than 30 grams of fat per day. The vitamin group participants had a higher incidence of diabetes than the placebo group. Liver biopsies were performed pre- and post-treatment. No significant side effects were noted in the 45 people who completed the trial. At the end of the six-month period, there was a small, yet statistically significant improvement in fibrosis scores in the vitamin group but not the placebo group. No difference was noted in the inflammation or necrosis scores between the groups. In general, there was a trend toward more improvement in fibrosis scores in those people with more severe fibrosis. Among non-diabetic participants, there was no significant change in fibrosis during the study in either group. Diabetics receiving vitamins E and C were found to have the most initial fibrosis and subsequently the most improvement in fibrosis during the study period. These results seem to indicate more benefit in diabetics with more severe fibrosis. However, because the number of diabetics in the vitamin group was not matched in the placebo group it cannot be said with certainty that people with NASH who take vitamins E and C will benefit. Further studies are needed to investigate the usefulness of vitamin E and C supplementation in people with NASH and to confirm the finding of selective improvement in diabetics with more severe fibrosis. Little or no change was seen in the level of liver enzymes during the study. Previous preliminary studies have reported similar findings of reduced liver inflammation and fibrosis and lowered liver enzymes following treatment with vitamin E. NASH may be best treated using a multifaceted approach aimed at addressing the underlying causes and preventing further damage. The results of this study are promising, as fibrosis scores actually improved over the study period. Since the amount of fibrosis is more predictive of disease severity than liver enzyme levels, an improvement in fibrosis may translate to a decreased likelihood of progression to cirrhosis and liver failure.
