Food groups and intermediate disease markers: a systematic review and network meta-analysis of randomized trials

Am J Clin Nutr. 2018 Sep 1;108(3):576-586. doi: 10.1093/ajcn/nqy151.

Abstract

Background: In previous meta-analyses of prospective observational studies, we investigated the association between food groups and risk of chronic disease.

Objective: The aim of the present network meta-analysis (NMA) was to assess the effects of these food groups on intermediate-disease markers across randomized intervention trials.

Design: Literature searches were performed until January 2018. The following inclusion criteria were defined a priori: 1) randomized trial (≥4 wk duration) comparing ≥2 of the following food groups: refined grains, whole grains, nuts, legumes, fruits and vegetables, eggs, dairy, fish, red meat, and sugar-sweetened beverages (SSBs); 2) LDL cholesterol and triacylglycerol (TG) were defined as primary outcomes; total cholesterol, HDL cholesterol, fasting glucose, glycated hemoglobin, homeostasis model assessment insulin resistance, systolic and diastolic blood pressure, and C-reactive protein were defined as secondary outcomes. For each outcome, a random NMA was performed, and for the ranking, the surface under the cumulative ranking curves (SUCRA) was determined.

Results: A total of 66 randomized trials (86 reports) comparing 10 food groups and enrolling 3595 participants was identified. Nuts were ranked as the best food group at reducing LDL cholesterol (SUCRA: 93%), followed by legumes (85%) and whole grains (70%). For reducing TG, fish (97%) was ranked best, followed by nuts (78%) and red meat (72%). However, these findings are limited by the low quality of the evidence. When combining all 10 outcomes, the highest SUCRA values were found for nuts (66%), legumes (62%), and whole grains (62%), whereas SSBs performed worst (29%).

Conclusion: The present NMA provides evidence that increased intake of nuts, legumes, and whole grains is more effective at improving metabolic health than other food groups. For the credibility of diet-disease relations, high-quality randomized trials focusing on well-established intermediate-disease markers could play an important role. This systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42018086753.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Animals
  • Beverages / analysis
  • Biomarkers / blood*
  • Cholesterol / blood
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Chronic Disease / prevention & control*
  • Diet*
  • Dietary Sugars / administration & dosage
  • Dietary Sugars / analysis
  • Fabaceae
  • Fishes
  • Food*
  • Fruit
  • Glycated Hemoglobin A / analysis
  • Humans
  • Meat
  • Network Meta-Analysis
  • Nuts
  • Randomized Controlled Trials as Topic
  • Triglycerides / blood
  • Whole Grains

Substances

  • Biomarkers
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Dietary Sugars
  • Glycated Hemoglobin A
  • Triglycerides
  • Cholesterol