Genomic analysis of diet composition finds novel loci and associations with health and lifestyle

TLDR

Macronutrient intake phenotypes are genetically correlated yet each has a partially distinct genetic architecture. We performed GWAS of relative macronutrient intake in 235,000 European‑ancestry individuals. We identified 21 lead SNPs (14 unique to a macronutrient), found protein intake associated with obesity, type 2 diabetes, and heart disease, whereas carbohydrate and sugar intake correlated negatively with waist measures and positively with physical activity, and fat intake showed no consistent health pattern, suggesting protein may contribute to metabolic dysfunction.

Abstract

Abstract We conducted genome-wide association studies (GWAS) of relative intake from the macronutrients fat, protein, carbohydrates, and sugar in over 235,000 individuals of European ancestries. We identified 21 unique, approximately independent lead SNPs. Fourteen lead SNPs are uniquely associated with one macronutrient at genome-wide significance ( P < 5 × 10 −8 ), while five of the 21 lead SNPs reach suggestive significance ( P < 1 × 10 −5 ) for at least one other macronutrient. While the phenotypes are genetically correlated, each phenotype carries a partially unique genetic architecture. Relative protein intake exhibits the strongest relationships with poor health, including positive genetic associations with obesity, type 2 diabetes, and heart disease ( r g ≈ 0.15–0.5). In contrast, relative carbohydrate and sugar intake have negative genetic correlations with waist circumference, waist-hip ratio, and neighborhood deprivation (| r g | ≈ 0.1–0.3) and positive genetic correlations with physical activity ( r g ≈ 0.1 and 0.2). Relative fat intake has no consistent pattern of genetic correlations with poor health but has a negative genetic correlation with educational attainment ( r g ≈−0.1). Although our analyses do not allow us to draw causal conclusions, we find no evidence of negative health consequences associated with relative carbohydrate, sugar, or fat intake. However, our results are consistent with the hypothesis that relative protein intake plays a role in the etiology of metabolic dysfunction.