Nonalcoholic Fatty Liver Disease: Nutritional Considerations

Fatty liver disease is, in many cases, responsive to diet changes. Preliminary research suggests that weight reduction on a low–fat, high–fiber diet may be an effective treatment for nonalcoholic fatty liver diseases. Although further clinical trials are needed to establish the role of diet in treating these conditions, the key issues are as follows: 

• Weight loss: Loss of excess weight may reduce the risk for nonalcoholic fatty liver disease. Compared with a rate of 20 percent in the general population, nonalcoholic fatty liver disease affects up to 75 percent of obese individuals. Gradual, moderate weight loss (about 10 percent of body weight) may lead to improvement in liver function. However, rapid weight loss exceeding 1 pound per week in children and 3.5 pounds a week in adults may result in worsening of the disease.
  
• Plant–based diets: Plant–based diets may be particularly helpful for both prevention and treatment of fatty liver disease. Clinical trials have not yet studied low–fat, high–fiber vegetarian diets for this disease. However, these diets typically cause weight loss and can lower the levels of blood fats (e.g., triglycerides) that contribute to nonalcoholic fatty liver disease. Such diets are also associated with reduced insulin resistance and greater antioxidant protection, compared with meat–based diets.
  
• Alcohol avoidance: Alcohol intake can raise blood triglyceride concentrations, which are elevated in a majority of individuals with nonalcoholic fatty liver disease. Consumption of more than 40 grams of alcohol per day doubles the risk of fatty liver and other liver diseases. Women may be affected at even lower levels of intake (e.g., 20 to 30 grams a day). 
  
• Antioxidants: Some evidence suggests a role for dietary antioxidants. Oxidative stress, which is the imbalance between potentially harmful oxidants and protective antioxidants, occurs in individuals with fatty liver. The result is DNA damage, alterations in proteins, destruction of cell membranes, and inflammation. However, clinical trials have yet to be performed to determine the benefit of dietary or supplemental antioxidants in the prevention or treatment of this disease.