A common polymorphism near the interleukin-6 gene modifies the association between dietary fat intake and insulin sensitivity

Abstract

Background

Increasing evidence suggests a role for inflammation in the development of type 2 diabetes. Elevated levels of inflammatory cytokines, including interleukin-6, have been associated with insulin resistance, and dietary lipids can increase cytokine production. The objective of this study was to determine whether a single nucleotide polymorphism near the IL6 gene (rs7801406) modifies the relationship between dietary fat and markers of insulin sensitivity.

Methods

Subjects were healthy men and women aged 20–29 years from the Toronto Nutrigenomics and Health Study. Dietary intake was estimated using a one-month semiquantitative food frequency questionnaire. Fasting blood samples were taken for genotyping and biomarker measurement.

Results

The single nucleotide polymorphism was not associated with any of the measures of insulin sensitivity. However, it modified the relationship between total dietary fat and the homeostasis model assessment of insulin resistance (P = 0.053 for interaction). Total fat intake was positively related to HOMA-IR in individuals homozygous for the G allele (β = 0.005 ± 0.002, P = 0.03), but not among heterozygotes. There was an inverse relationship between total fat intake and HOMA-IR in individuals who were homozygous for the A allele (β = −0.012 ± 0.006, P = 0.047).

Conclusion

These findings suggest that dietary fat influences insulin sensitivity differently depending on genotype.

Keywords:

• interleukin-6
• insulin sensitivity
• nutrigenomics
• dietary fat

Acknowledgments

BGB, MK, and AB received support from the Public Health Agency of Canada. The authors thank Andre Villages, Office of Biotechnology, Genomics and Population Health, Public Health Agency of Canada, for his help in identifying the proxy single nucleotide polymorphisms and the linkage disequilibrium analysis. AE-S holds a Canada Research Chair in Nutrigenomics.

Disclosure

The authors report no conflicts of interest in this work.