Randomized Controlled Trial of a MUFA or Fiber-Rich Diet on Hepatic Fat in Prediabetes

J Clin Endocrinol Metab. 2017 May 1;102(5):1765-1774. doi: 10.1210/jc.2016-3722.

Abstract

Context: Increased prevalence of type 2 diabetes mellitus and prediabetes worldwide is attributed in part to an unhealthy diet.

Objective: To evaluate whether 12 weeks of high monounsaturated fatty acid (MUFA) or fiber-rich weight-maintenance diet lowers hepatic fat and improves glucose tolerance in people with prediabetes.

Design: Subjects underwent a [6, 6-2H2]-labeled 75-g oral glucose tolerance test to estimate hepatic insulin sensitivity and liver fat fraction (LFF) using magnetic resonance spectroscopy before and after intervention.

Setting: Mayo Clinic Clinical Research Trials Unit.

Participants: 43 subjects with prediabetes.

Intervention: Subjects were randomized into three isocaloric weight-maintaining diets containing MUFA (olive oil), extra fiber, and standard US food (control-habitual diet).

Outcome measures: LFF, glucose tolerance, and indices of insulin action and secretion.

Results: Body weight was maintained constant in all groups during the intervention. Glucose and hormonal concentrations were similar in all groups before, and unchanged after, 12 weeks of intervention. LFF was significantly lower after intervention in the MUFA group (P < 0.0003) but remained unchanged in the fiber (P = 0.25) and control groups (P = 0.45). After 12 weeks, LFF was significantly lower in the MUFA than in the control group (P = 0.01), but fiber and control groups did not differ (P = 0.41). Indices of insulin action and secretion were not significantly different between the MUFA and control groups after intervention (P ≥ 0.11), but within-group comparison showed higher hepatic (P = 0.01) and total insulin sensitivity (P < 0.04) with MUFA.

Conclusions: Twelve weeks of a MUFA diet decreases hepatic fat and improves both hepatic and total insulin sensitivity.

Trial registration: ClinicalTrials.gov NCT01729078.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Aged
  • Chondroitin Sulfate Proteoglycans / genetics
  • Deuterium
  • Dietary Fats / therapeutic use
  • Dietary Fiber / therapeutic use*
  • Fatty Acids, Monounsaturated / therapeutic use*
  • Female
  • Genetic Predisposition to Disease
  • Glucose Tolerance Test
  • Humans
  • Insulin Resistance*
  • Lectins, C-Type / genetics
  • Lipase / genetics
  • Liver / metabolism*
  • Magnetic Resonance Spectroscopy
  • Male
  • Membrane Proteins / genetics
  • Metabolomics
  • Middle Aged
  • Nerve Tissue Proteins / genetics
  • Non-alcoholic Fatty Liver Disease / genetics
  • Non-alcoholic Fatty Liver Disease / metabolism
  • Olive Oil / therapeutic use*
  • Polymorphism, Single Nucleotide
  • Prediabetic State / diet therapy*
  • Prediabetic State / metabolism
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Transcription Factor 7-Like 2 Protein / genetics

Substances

  • Adaptor Proteins, Signal Transducing
  • Chondroitin Sulfate Proteoglycans
  • Dietary Fats
  • Dietary Fiber
  • Fatty Acids, Monounsaturated
  • GCKR protein, human
  • Lectins, C-Type
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Olive Oil
  • SREBF1 protein, human
  • Sterol Regulatory Element Binding Protein 1
  • TCF7L2 protein, human
  • Transcription Factor 7-Like 2 Protein
  • NCAN protein, human
  • Deuterium
  • Lipase
  • adiponutrin, human

Associated data

  • ClinicalTrials.gov/NCT01729078