Restricting Fructose Consumption May Reduce Liver Fat Accumulation

SAN DIEGO — Restricting dietary fructose, but not calories, in obese Latino and African-American children may decrease liver fat and the conversion of sugar to fat in the liver, according to a new study presented at ENDO 2105. 

Previous studies have shown that consuming high sugar, specifically fructose, is associated with liver fat accumulation and/or hypertriglyceridemia, which may increase the risk for type 2 diabetes and cardiovascular disease (CVD).  

 “A lot of correlative studies have linked fructose consumption to fatty liver and metabolic syndrome, but the causal link is more difficult to document. We wanted to see if removing fructose from the diets of obese children with high habitual fructose/sugar intake could reverse some of these effects. We substituted foods containing complex carbohydrates, such as is found in bread, pasta, rice, etc.,” said lead study author Jean-Marc Schwarz, PhD, who is a professor of biochemistry at Touro University California in Vallejo and an associate research endocrinologist at the University of California, San Francisco.

Dr. Schwarz and his colleagues studied 22 obese Latino and African American children aged 9 to 18 years who habitually ate high-sugar foods. The cohort included 10 boys and 12 girls with a BMI z-score of 2.4.

For 10 days, the researchers provided all the children’s meals, which contained the same caloric and macronutrient composition as their standard diet, but the sugar was substituted with other carbohydrates. 

The children were weighed daily, and their diets were adjusted to maintain their baseline weight. The conversion of sugar to fat in their liver was measured with Gas Chromatography/Mass Spectrometry (GC/MS) using stable isotope tracers. The liver fat percentage was determined by Magnetic Resonance Spectroscopy (MRS).

After 10 days of fructose restriction, the children’s conversion of sugar to fat declined by about 58% (P<.001) and their liver fat decreased by about 29% (P<.001).

The researchers found that hepatic de novolipogenesis (DNL) during feeding was significantly reduced with fructose restriction, beginning 50 minutes after initiation of tracer/feeding and continuing throughout the tracer/feeding procedure, on days 0 and 10 (P<.003).

Dr. Schwarz said he did not expect to see such a dramatic effect.

“The results of this short-term study suggest that reducing dietary sugar intake, for example, by decreasing consumption of soda may be an effective non-pharmacologic way to reduce lipogenesis and liver fat in obese children — a population that is at high risk for hepatic steatosis, prediabetes and lipid disorders,” Dr. Schwarz told Endocrinology Advisor.

He said even though fructose and high fructose corn syrup consumption are high in the U.S. population, dietary fructose restriction is an achievable goal and it could bring a myriad of important health benefits.  

Dr. Schwarz also said the results from this study demonstrate that the detrimental effects of fructose can be reversed by reducing fructose consumption. Further, hepatic DNL may be an important pathogenic mechanism leading to liver fat accumulation in children, and it is one that can be reversed by something as simple as fructose restriction, he noted.

Reference

1. Schwarz JM et al. Abstract THR-549. Presented at: The Endocrine Society’s 97th Annual Meeting & Expo (ENDO 2015); March 5-8, 2015; San Diego.