Jeffrey B. Schwimmer
An 8-week diet low in free sugar content significantly improved hepatic steatosis among adolescent boys with nonalcoholic fatty liver disease compared with their usual diet, according to a study published in JAMA.
“There are no approved pharmacological therapies for the treatment of NAFLD,” Jeffrey B. Schwimmer, MD, from the University of California in San Diego, and colleagues wrote. “Pediatric guidelines recommend ‘lifestyle modification to improve diet,’ but do not support one specific diet over another because of the limited available evidence. Among the various dietary options, limiting sugar intake is easily targetable in part because sugar is not a required nutrient.”
According to Scwhimmer and colleagues, data from the National Health and Nutrition Examination Survey showed that sugar added to foods and beverages during processing accounted for 13% to 17% of dietary calories among U.S. children and adolescents. In contrast, the current WHO guidelines state that daily free sugar intake should be limited to less than 10% for all people and less than 5% in specific circumstances.
To ensure that daily free sugar intake was well below these targets, the researchers set a limit of less than 3% of daily calories in the intervention diet group. The study comprised 40 adolescent patients with NAFLD whom the researchers randomly assigned 1:1 to either the intervention group or the usual diet group.
Eighteen of the 20 patients in the intervention group reported maintaining the 3% limited diet during the 8-week study, which was designed and provided by the research team. The researchers note that use of artificial sweeteners was prohibited in the intervention diet due to the ongoing controversy regarding their effect on body weight and insulin sensitivity.
At week 8, hepatic steatosis decreased more significantly among patients in the intervention group from baseline (25% vs. 17%) compared with the usual diet group (21% vs. 20%) for a mean adjusted difference of 6.23% (95% CI, 9.45% to 3.02%).
Additionally, alanine aminotransferase (P < .001), aspartate aminotransferase (P = .005), gamma-glutamyl transpeptidase (P < .001), and total cholesterol (P = .006) were significantly lower in the intervention group at 8 weeks from baseline compared with the usual diet group.
“Despite the time spent by physicians counseling patients and families, implementation, long-term adherence, and sustainability of a healthy diet remain challenges for patients, researchers, and physicians,” Schwimmer and colleagues wrote. “This clinical trial has shown that children and families can follow a diet low in free sugars for up to 8 weeks when the research team plans, purchases, and provides all meals. This is not practical to generalize widely; however, it shows that a low sugar diet reduces biomarkers of NAFLD activity at least in the short term.”
Schwimmer and colleagues noted several other limitations to the study, including an all-male patient population and a higher proportion of Hispanic patients compared with other ethnicities — preventing generalization for all adolescent patients — as well as self-reported adherence.
“Further studies will be needed to assess longer-term clinical benefit such as preventing progression or lowering the incidence of complications and to solve the challenges of implementing a low free sugar diet for patients with NAFLD in clinical practice,” the researchers concluded. – by Talitha Bennett
Disclosure: Schwimmer reports he has received research support from Galmed and Intercept. Please see the full study for the other authors’ relevant financial disclosures.