Nonalcoholic fatty liver disease is associated with excessive calorie intake rather than a distinctive dietary pattern

A study published in Medicine sought to characterize the dietary patterns of patients with nonalcoholic fatty liver disease (NAFLD) and to assess the efficacy of dietary interventions on NAFLD related outcomes.

Researchers collected a total of 55 NAFLD patients and 88 controls to complete the study in northern Germany. All participants were subjected to a physical examination including blood analysis to measure blood glucose, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, alanine aminotransferase (ALT), aspartate transaminase (AST), and gamma-glutamyl transpeptidase (γGT). The extent of liver fibrosis was also determined. All participants were required to complete a food frequency questionnaire (FFQ), and describe their lifestyle as sedentary, low-active, or active. Nutritional data was analyzed and normalized to 1000 kcal caloric intake and analyzed again.

Researchers found that the mean body weight, body mass index (BMI), waist circumference, fat mass, ALT, AST, γGT, triglycerides, and blood glucose were all significantly higher in the NAFLD group compared to the control. HDL was significantly lower in the NAFLD group compared to the control. Of the NAFLD patients, 13 reported a sedentary lifestyle, 22 reported a low-active lifestyle, and 20 reported an active lifestyle.

The NAFLD patients consumed significantly more calories per day. The NAFLD group consumed a median daily energy intake of 2739 kcals (range: 1009-5941kcals) whereas the control consumed a median of 2173kcals (range: 1199-4320kcals). Overall, the NAFLD patients consumed more fat, carbohydrates, and protein than the control but fiber intake was comparable between both groups. When researchers normalized the nutritional data per 1000 kcals they found that the NAFLD patients had significantly lower fiber and mineral intake and significantly more protein and glucose intake per 1000 kcals compared to the controls. The fructose, carbohydrate, and fat intake per 1000 kcals in the NAFLD group was not significantly different than the controls.

A total of 24 NAFLD patients participated in a 6 month follow up study in which patients received up to 5 sessions of dietary counselling every 4 to 6 weeks. At the 6 month follow up a second FFQ was administered and patients were underwent reevaluation. The mean weight loss was 3.4%. Patients consumed fewer calories daily compared to baseline diet. Carbohydrate, protein, glucose, and fructose intake per 1000kcals did not change significantly from baseline. Conversely, patients consumed more fiber and more fat per 1000kcals at the follow up than at baseline. The ATL levels for all participants at follow up were significantly lower than at baseline; however researchers note “due to the small number of patients who were available for follow-up, we found no association between weight loss or reduction of specific nutrition components and ALT improvement.”

Researchers conclude “We found an energy-dense diet with relatively high amounts of protein and glucose, but poor in fiber and minerals to be associated with NAFLD…there was no significant difference in fructose ingestion normalized to the daily caloric intake. However, this does not exclude a dose-dependent hepatotoxic effect of fructose.”