Effect of a Low Free Sugar Diet vs Usual Diet on Nonalcoholic Fatty Liver Disease in Adolescent Boys: A Randomized Clinical Trial
来源：JAMA. 2019;321(3):256-265. doi:10.1001/jama.2018.20579
Key Points 关键点
Question Does restricting dietary free sugars reduce hepatic steatosis in children with nonalcoholic fatty liver disease?
Findings In this randomized clinical trial that included 40 adolescent boys aged 11 to 16 years with nonalcoholic fatty liver disease followed up for 8 weeks, provision of a diet low in free sugars compared with usual diet resulted in a greater reduction in hepatic steatosis from 25% to 17% in the low free sugar diet group and from 21% to 20% in the usual diet group, a statistically significant difference of −6.23% when adjusted for baseline.
Meaning These preliminary findings suggest potential benefit of a diet low in free sugars for children with nonalcoholic fatty liver disease, but further research is needed to assess long-term and clinical outcomes.
Importance Pediatric guidelines for the management of nonalcoholic fatty liver disease (NAFLD) recommend a healthy diet as treatment. Reduction of sugary foods and beverages is a plausible but unproven treatment.
Objective To determine the effects of a diet low in free sugars (those sugars added to foods and beverages and occurring naturally in fruit juices) in adolescent boys with NAFLD.
Design, Setting, and Participants An open-label, 8-week randomized clinical trial of adolescent boys aged 11 to 16 years with histologically diagnosed NAFLD and evidence of active disease (hepatic steatosis >10% and alanine aminotransferase level ≥45 U/L) randomized 1:1 to an intervention diet group or usual diet group at 2 US academic clinical research centers from August 2015 to July 2017; final date of follow-up was September 2017.
Interventions The intervention diet consisted of individualized menu planning and provision of study meals for the entire household to restrict free sugar intake to less than 3% of daily calories for 8 weeks. Twice-weekly telephone calls assessed diet adherence.
Usual diet participants consumed their regular diet.
Main Outcomes and Measures The primary outcome was change in hepatic steatosis estimated by magnetic resonance imaging proton density fat fraction measurement between baseline and 8 weeks. The minimal clinically important difference was assumed to be 4%. There were 12 secondary outcomes, including change in alanine aminotransferase level and diet adherence.
Results Forty adolescent boys were randomly assigned to either the intervention diet group or the usual diet group (20 per group; mean(SD) age, 13.0(1. 9）years; most were Hispanic 95%) and all completed the trial. The mean decrease in hepatic steatosis from baseline to week 8 was significantly greater for the intervention diet group (25% to 17%) vs the usual diet group (21% to 20%) and the adjusted week 8 mean difference was −6.23% (95% CI, −9.45% to −3.02%; P < .001).
结果：40例青少年男性随机分为干预饮食组和常规饮食组（每组20例，平均年龄13±1.9岁，95%为白种人），所有患儿均完成研究。自基线开始随访8周后，干预饮食组(25% to 17%) 脂肪变性的平均下降率比常规饮食组(21% to 20%) 显著升高，校正后8周平均差异为−6.23% (95% CI, −9.45% to −3.02%; P <0 .001)。
Of the 12 prespecified secondary outcomes, 7 were null and 5 were statistically significant including alanine aminotransferase level and diet adherence. The geometric mean decrease in alanine aminotransferase level from baseline to 8 weeks was significantly greater for the intervention diet group (103 U/L to 61 U/L) vs the usual diet group (82 U/L to 75 U/L) and the adjusted ratio of the geometric means at week 8 was 0.65 U/L (95% CI, 0.53 to 0.81 U/L; P < .001).
12个预先设置的次要终点中，7个无效，5个有显著性改变，包括ALT水平和饮食依从性的改变。自基线开始随访8周后，干预饮食组 (103 U/L to 61 U/L) 的ALT水平几何平均减少幅度明显高于常规饮食组(82 U/L to 75 U/L) ，8周时几何均数的校正比率为0.65 U/L (95% CI, 0.53 to 0.81 U/L; P < 0.001)。
Adherence to the diet was high in the intervention diet group (18 of 20 reported intake of <3% of calories from free sugar during the intervention). There were no adverse events related to participation in the study.
Conclusions and Relevance In this study of adolescent boys with NAFLD, 8 weeks of provision of a diet low in free sugar content compared with usual diet resulted in significant improvement in hepatic steatosis. However, these findings should be considered preliminary and further research is required to assess long-term and clinical outcomes.