Effect of fructose consumption on insulin sensitivity in nondiabetic subjects: a systematic review and meta-analysis of diet-intervention trials

Am J Clin Nutr. 2016 Dec;104(6):1562-1576. doi: 10.3945/ajcn.116.137786. Epub 2016 Nov 9.

Abstract

Background: High fructose consumption has been suggested to contribute to several features of metabolic syndrome including insulin resistance, but to our knowledge, no previous meta-analyses have investigated the effect of fructose on insulin sensitivity in nondiabetic subjects.

Objective: We performed a systematic review and meta-analysis of controlled diet-intervention studies in nondiabetic subjects to determine the effect of fructose on insulin sensitivity.

Design: We searched MEDLINE, EMBASE, and the Cochrane Library for relevant trials on the basis of predetermined eligibility criteria. Two investigators independently performed the study selection, quality assessment, and data extraction. Results were pooled with the use of the generic inverse-variance method with random effects weighting and were expressed as mean differences (MDs) or standardized mean differences (SMDs) with 95% CIs.

Results: Twenty-nine articles that described 46 comparisons in 1005 normal-weight and overweight or obese participants met the eligibility criteria. An energy-matched (isocaloric) exchange of dietary carbohydrates by fructose promoted hepatic insulin resistance (SMD: 0.47; 95% CI: 0.03, 0.91; P = 0.04) but had no effect on fasting plasma insulin concentrations (MD: -0.79 pmol/L; 95% CI: -6.41, 4.84 pmol/L; P = 0.78), the homeostasis model assessment of insulin resistance (HOMA-IR) (MD: 0.13; 95% CI: -0.07, 0.34; P = 0.21), or glucose disposal rates under euglycemic hyperinsulinemic clamp conditions (SMD: 0.00; 95% CI: 20.41, 0.41; P = 1.00). Hypercaloric fructose (∼25% excess of energy compared with that of the weight-maintenance control diet) raised fasting plasma insulin concentrations (MD: 3.38 pmol/L; 95% CI: 0.03, 6.73 pmol/L; P < 0.05) and induced hepatic insulin resistance (SMD: 0.77; 95% CI: 0.28, 1.26; P < 0.01) without affecting the HOMA-IR (MD: 0.18; 95% CI: -0.02, 0.39; P = 0.08) or glucose disposal rates (SMD: 0.10; 95% CI: -0.21, 0.40; P = 0.54). Results may have been limited by the low quality, small sample size, and short duration (mostly <60 d) of included trials.

Conclusions: Short-term fructose consumption, in isocaloric exchange or in hypercaloric supplementation, promotes the development of hepatic insulin resistance in nondiabetic adults without affecting peripheral or muscle insulin sensitivity. Larger and longer-term studies are needed to assess whether real-world fructose consumption has adverse effects on insulin sensitivity and long-term outcomes.

Keywords: fructose; glucose clamp; glucose disposal; insulin; insulin resistance; meta-analysis.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Blood Glucose / metabolism
  • Body Weight
  • Databases, Factual
  • Diabetes Mellitus
  • Diet*
  • Dietary Carbohydrates / administration & dosage
  • Fasting
  • Fructose / administration & dosage
  • Fructose / adverse effects*
  • Humans
  • Insulin / blood
  • Insulin Resistance*
  • Randomized Controlled Trials as Topic

Substances

  • Blood Glucose
  • Dietary Carbohydrates
  • Insulin
  • Fructose