ATLANTA (Jan. 25, 2019) – Miriam Vos, MD, MSPH, a Pediatric Hepatologist, Director of the Nonalcoholic Fatty Liver Disease at Children’s Healthcare of Atlanta and Professor of Pediatrics at Emory University School of Medicine, is senior author of a new study published this week in JAMA. The randomized clinical study of adolescent boys with nonalcoholic fatty liver disease (NAFLD) found that a diet low in free sugars—meaning those sugars added to foods and beverages, and occurring naturally in fruit juices—resulted in significant improvement in NAFLD compared to a usual diet.
NAFLD is the most common liver disease in children, and it significantly increased from 1988 to 2010. NAFLD is associated with increased risk of Type 2 diabetes, end-stage liver disease, liver cancer and cardiovascular disease, thus diagnosis and prompt treatment is very important to long-term health.
“Although pediatric guidelines for managing nonalcoholic fatty liver disease recommend a healthy diet, focused reduction of sugary foods and beverages was an unproven treatment,” Dr. Vos said. “Our results show that if a child with NAFLD consumes a very low amount of sugars in their diet, both fat and inflammation in the liver improves. We are excited by the highly significant results but also realize that a longer study will be needed in order to understand if sugar reduction is sufficient to ‘cure’ NAFLD.”
The clinical study, conducted from August 2015 to July 2017 at Emory University, Children’s and University of California–San Diego School of Medicine, included 40 boys aged 11 to 16 years with NAFLD, 95% of whom were Hispanic. The participants were randomized into two groups. Half of the boys, along with their families, were provided a diet low in free sugars (less than 3% of daily caloric intake), and half ate their usual diets. Twice a week, telephone calls assessed adherence to the diet. The boys with a reduced free sugar diet had a reduction in NAFLD from 25% to 17%, while the boys with a usual diet had a reduction in NAFLD from 21% to 20%. Reducing free sugars in the diet involves decreasing glucose, fructose, and sucrose commonly consumed in sweetened foods and beverages and in naturally sweet fruit juices.
The primary outcome measured was change in hepatic steatosis, estimated by magnetic resonance imaging proton density fat fraction measurement—a precise, state-of-the-art method to quantify lipids in liver. Twelve secondary outcomes were also measured, with several having significant changes as well. The decrease in alanine aminotransferase level (a test used to measure liver enzymes and liver function) was significantly greater for the intervention diet group than for the usual diet group, and decrease in cholesterol levels was significantly greater in the intervention group. In addition, adherence to the diet was high, with 18 of 20 participants/families reporting intake of fewer than 3% of calories from free sugar during the intervention. There were no adverse events related to participation in the study.
“Despite the counseling provided by physicians to patients and families, implementing an effective sugar-reducing diet, along with long-term adherence and sustainability are often very challenging,” notes first author Jeffrey B. Schwimmer, MD, Professor of Clinical Pediatrics at UC–San Diego. “Our study shows that children and their families can follow a diet low in free sugars for up to eight weeks when the research team plans, purchases and provides all meals. Although this would not be widely practical, it shows that this kind of intervention reduces NAFLD biomarkers at least in the short-term.”
The authors note that further studies will be needed to demonstrate longer-term clinical benefit in both girls and boys and all ethnicities, and to solve the challenges of implementing a diet low in free sugars for patients in clinical practice.