Starch Digestion-Related Amylase Genetic Variant Affects 2-Year Changes in Adiposity in Response to Weight-Loss Diets: The POUNDS Lost Trial

Abstract

Salivary and pancreatic amylases (encoded by AMY1 and AMY2 genes, respectively) are responsible for digesting starchy foods. AMY1 and AMY2 show copy number variations that affect differences in amylase amount and activity, and AMY1 copies have been associated with adiposity. We investigated whether genetic variants determining amylase gene copies are associated with 2-year changes in adiposity among 692 overweight and obese individuals who were randomly assigned to diets varying in macronutrient content. We found that changes in body weight (BW) and waist circumference (WC) were significantly different according to the AMY1-AMY2 rs11185098 genotype. Individuals carrying the A allele (indicating higher amylase amount and activity) showed a greater reduction in BW and WC at 6, 12, 18, and 24 months than those without the A allele (P < 0.05 for all). The association was stronger for long-term changes compared with short-term changes of these outcomes. The genetic effects on these outcomes did not significantly differ across diet groups. In conclusion, the genetic variant determining starch metabolism influences the response to weight-loss dietary intervention. Overweight and obese individuals carrying the AMY1-AMY2 rs11185098 genotype associated with higher amylase activity may have greater loss of adiposity during low-calorie diet interventions.

Trial registration: ClinicalTrials.gov NCT00072995.

© 2017 by the American Diabetes Association.

Figures

Figure 1

Trajectories of BW (A) and WC (B) over 2 years in participants according to the AMY1-AMY2 rs11185098 genotype. Data are after adjustment for age, sex, ethnicity, diet group, and value for the respective outcome traits at the baseline examination (either BW or WC).

Figure 2

Effects of AMY1-AMY2 rs11185098 genotype on trajectories of changes in fasting glucose concentrations over 2 years in response to weight-loss diets. Data are after adjustment for age; sex; ethnicity; diet group; baseline values of BMI, WC, and fasting glucose; antihypertensive medication use; lipid-lowering medication use; and concurrent weight changes. m, months.