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
- 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.