Genetic variation in the AMY1 gene is associated with dietary carbohydrate and starch intake in a young adult population

Abstract

BackgroundGenetic variation contributes to individual differences in energy and nutrient intake and may be a contributing factor to the selection of certain foods and macronutrient preference. Salivary amylase is encoded by the AMY1 gene, which displays high copy number variation (CNV) and plays an important role in starch digestion. Research has found that AMY1 CNV is positively correlated with both salivary amylase concentration and activity and higher AMY1 copy numbers have been found in populations with high starch diets. Individual single nucleotide polymorphisms (SNPs) near the amylase genes have been found to correlate with AMY1 copy number within populations. The objective of this study was to determine whether common variants in the AMY1 gene are associated with habitual dietary intake.MethodsFasting blood samples were drawn from a total of 1,600 ethno‐culturally diverse participants aged 20–29 years from the Toronto Nutrigenomics and Health Study for genotyping of 9 SNPs associated with AMY1 copy number: rs4244372 (T/A), rs11577390 (C/T), rs1566154 (A/G), rs10881197(G/C), rs2132957 (A/G), rs11185098(G/A), rs1999478(C/A), rs1330403(A/G) and rs6696797(A/G). Dietary intake was assessed using a one‐month, 196‐item Toronto‐modified Willett food frequency questionnaire. An analysis of covariance adjusted for age, sex, ethnicity, BMI, and physical activity was used to determine the association between AMY1 genotypes and dietary intake.ResultsAmong Caucasians (n = 620), carriers of the minor allele in rs10881197 had a significantly lower energy intake (1838 vs 2089 kcal/day, p = 0.005). Carriers of the minor allele in rs11185098 had significantly higher total carbohydrate (CHO) and starch intakes (273 vs 266 g CHO/day, p =0.03 and 122 vs 117g starch/day, p= 0.02 respectively). Among East Asians (n = 465), carriers of the minor allele in rs1999478 had significantly higher total energy and sugar intakes (1985 vs 1828 kcal/day, p = 0.02 and 113 vs 105 g sugar/day, p = 0.03 respectively). No other associations were observed between AMY1 variants and carbohydrate or starch intake.ConclusionPolymorphisms in the AMY1 gene are associated with dietary intake patterns. Identifying the genetic determinants of dietary intake and food preference may enhance our understanding of excessive caloric intake and obesity, a common risk factor of many chronic conditions and provide further evidence to support the use of personalized nutrition recommendations.Support or Funding InformationResearch support from Mitacs