Protein & Cholesterol May Increase Risk Of Cirrhosis & Hepatocellular Carcinoima
Dietary changes -- in particular limiting protein consumption -- were traditionally recommended for people with advanced liver disease, but diet modification is no longer regarded as a mainstay of liver disease management. As this shift suggests, much remains to be learned about the impact of food on liver disease progression.
George Ioannou of the Veterans Affairs Puget Sound Health Care System and colleagues sought to determine whether dietary intake is associated with the risk of hospitalization or death related to cirrhosis or liver cancer, which are often the result of chronic hepatitis B or C virus infection.
The researchers evaluated 9221 adults without evidence of cirrhosis at study entry or during the first 5 years of follow-up. Participants were subsequently followed for an average of 13.3 years as part of the first National Health and Nutrition Examination Survey (NHANES). Dietary intake was determined at baseline using a 24-hour food consumption recall questionnaire.
The investigators looked at associations between advanced liver disease outcomes and various potential risk factors and confounders, including patient sex, race/ethnicity, age, education, U.S. geographical region, body mass index, subscapular-to-triceps skinfold ratio (a measure of body fat), diabetes, and daily consumption of protein, carbohydrates, fat, tea or coffee, and alcohol.
During follow-up, 123 of 9221 participants (1.3%) were diagnosed with cirrhosis (118 cases) or liver cancer (cases 5), according to hospital records or death certificates (36 were diagnosed only on the basis of death certificates).
Participants who reported a diet high in protein were at a higher risk for hospitalization or death due to cirrhosis or liver cancer (P = 0.001).
Individuals who reported a diet high in carbohydrates were at a lower risk for advanced liver disease outcomes (P = 0.003), after adjusting for potential confounders.
Although total fat consumption was not significantly associated with the risk of cirrhosis or liver cancer, cholesterol consumption was associated with higher risk (P = 0.007).
However serum cholesterol levels -- which do not always reflect dietary cholesterol consumption -- were not associated with risk of cirrhosis or liver cancer.
"Many determinants of liver disease progression are currently unknown, as evidenced by the fact that we cannot predict accurately which patients with any of the major liver diseases (hepatitis C virus, hepatitis B virus, nonalcoholic fatty liver disease, and alcoholic liver disease) will progress to cirrhosis and which ones will have a relatively benign course," the investigators wrote. "Our study raises the possibility that dietary factors may be important, modifiable, and hitherto unrecognized determinants of liver disease progression."
This study adds further support to a growing body of evidence linking liver disease with the metabolic syndrome, a constellation of manifestations including insulin resistance, high blood pressure, elevated blood lipids, and abdominal obesity.
Rather than severely restricting protein, most experts now recommend a balanced diet low in fat and high in fruits, vegetables, and whole grains to patients with liver disease.
Veterans Affairs Puget Sound Health Care System, Seattle , WA ; University of Washington , Seattle , WA .