Cutting Sugar Intake Improves Liver Function in Obese Children

Short-term isocaloric fructose restriction is associated with decreased liver fat, visceral fat, and de novo lipogenesis, and improved insulin kinetics in children with obesity, according to a recent study.

It is well-established that sugar intake is associated with obesity, type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular disease. However, de novo lipogenesis, or the conversion of fructose to fat in the liver, may be a modifiable pathogenetic pathway.
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To explore the specific impact of sugar restriction on de novo lipogenesis, the researchers assessed 41 Latino and African American children with obesity with a habitual high sugar consumption of more than 50 g/d. Patient ages ranged from 9 to 18 years.

The researchers provided participants with meals for 9 days, which were similar in macronutrient and energy composition to their usual diets but sugar was substituted with starch. Meals contained 4% of total kilocalories of sugar.

Metabolic assessments were conducted prior to and after fructose restriction. Magnetic resonance spectroscopy and imaging were used to measure liver fat, visceral fat, and subcutaneous fat. Stable isotope tracers and gas chromatography/mass spectrometry were used to determine the fractional de novo lipogenesis area under the curve value. Glucose tolerance tests were used to calculate insulin kinetics. Change from baseline to day 10 was measured in each child via paired analyses.

Results indicated that liver fat had decreased from a median 7.2% at baseline to 3.8% on day 10. Visceral fat had decreased from 123 cm³ to 110 cm³. The de novo lipogenesis area under the curve had decreased from 68% to 26%, and insulin kinetics had improved. These changes occurred regardless of baseline liver fat, the researchers noted.

“Short-term (9 days) isocaloric fructose restriction decreased liver fat, [visceral fat], and [de novo lipogenesis], and improved insulin kinetics in children with obesity,” the researchers concluded. “These findings support efforts to reduce sugar consumption.”

—Christina Vogt

Reference:

Schwarz JM, Noworolski SM, Erkin-Cakmak A, et al. Effects of dietary fructose restriction on liver fat, de novo lipogenesis, and insulin kinetics in children with obesity. Gastroenterology. 2017;153(3):743-752.  https://dx.doi.org/10.1053/j.gastro.2017.05.043.