Short-term sugar reduction yields metabolic improvements in obese children
Restriction of isocaloric fructose for up to 9 days appears to improve liver fat, visceral fat (VAT), de novo lipogenesis (DNL) and insulin kinetics in children with obesity, a study has found.
The study included 41 children aged 9 to 18 years old fed with a controlled meal for 9 days. All meals had the same energy and macronutrient composition as the standard diet of the children, although sugar was replaced with starch, yielding a final fructose content of 4 percent of total kcal.
Metabolic parameters were assessed prior to and after fructose restriction. Liver fat, VAT and subcutaneous fat were evaluated using magnetic resonance spectroscopy and imaging. The fractional DNL area under the curve value was estimated by stable isotope tracers and gas chromatography/mass spectrometry. Oral glucose tolerance tests were also performed to calculate insulin kinetics.
On day 10, a decrease from baseline was observed in liver fat (from 7.2 to 3.8 percent; p<0.001), VAT (from 123 to 110 cm3; p<0.001) and the DNL area under the curve (from 68 to 26 percent; p<0.001). Insulin kinetics also improved (p<0.001) at intervention completion. These changes occurred regardless of baseline liver fat.
Fructose has unique metabolic and neuroendocrine properties: 1) being metabolized almost exclusively in the liver, 2) serving as a substrate for DNL and driving hepatic triglyceride synthesis and accumulation, 3) engaging in nonenzymatic fructation and reactive oxygen species formation which results in cellular dysfunction, and 5) stimulating the nucleus accumbens, leading to increased reward and continued ingestion. Furthermore, the substance does not suppress the hunger hormone ghrelin, and this causes excessive consumption. [Obesity (Silver Spring) 2016;24:453–460]
In previous studies, fructose has been suggested to increase blood pressure by promoting sympathetic activity, decreasing urinary sodium excretion, increasing gut sodium absorption and elevating uric acid. In children, fructose may increase both systolic and diastolic blood pressure levels.
The present finding that short-term isocaloric fructose restriction may result in metabolic improvements in children with obesity underscores the importance of efforts to reduce sugar consumption, researchers said.