Interactions of dietary whole-grain intake with fasting glucose- and insulin-related genetic loci in individuals of European descent: a meta-analysis of 14 cohort studies

Diabetes Care. 2010 Dec;33(12):2684-91. doi: 10.2337/dc10-1150. Epub 2010 Aug 6.

Abstract

Objective: Whole-grain foods are touted for multiple health benefits, including enhancing insulin sensitivity and reducing type 2 diabetes risk. Recent genome-wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) associated with fasting glucose and insulin concentrations in individuals free of diabetes. We tested the hypothesis that whole-grain food intake and genetic variation interact to influence concentrations of fasting glucose and insulin.

Research design and methods: Via meta-analysis of data from 14 cohorts comprising ∼ 48,000 participants of European descent, we studied interactions of whole-grain intake with loci previously associated in GWAS with fasting glucose (16 loci) and/or insulin (2 loci) concentrations. For tests of interaction, we considered a P value <0.0028 (0.05 of 18 tests) as statistically significant.

Results: Greater whole-grain food intake was associated with lower fasting glucose and insulin concentrations independent of demographics, other dietary and lifestyle factors, and BMI (β [95% CI] per 1-serving-greater whole-grain intake: -0.009 mmol/l glucose [-0.013 to -0.005], P < 0.0001 and -0.011 pmol/l [ln] insulin [-0.015 to -0.007], P = 0.0003). No interactions met our multiple testing-adjusted statistical significance threshold. The strongest SNP interaction with whole-grain intake was rs780094 (GCKR) for fasting insulin (P = 0.006), where greater whole-grain intake was associated with a smaller reduction in fasting insulin concentrations in those with the insulin-raising allele.

Conclusions: Our results support the favorable association of whole-grain intake with fasting glucose and insulin and suggest a potential interaction between variation in GCKR and whole-grain intake in influencing fasting insulin concentrations.

Publication types

  • Meta-Analysis

MeSH terms

  • Adult
  • Aged
  • Blood Glucose / genetics
  • Blood Glucose / metabolism*
  • Edible Grain*
  • European Continental Ancestry Group
  • Fasting / blood*
  • Female
  • Genetic Loci / genetics*
  • Genome-Wide Association Study
  • Genotype
  • Humans
  • Insulin / blood*
  • Insulin / genetics
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide / genetics

Substances

  • Blood Glucose
  • Insulin