Association of the melanocortin-4 receptor V103I polymorphism with dietary intake in severely obese persons

Abstract

Background: Several studies have reported that carriers of the 103I allele of the melanocortin-4 receptor (MC4R) gene had lower body weight than did persons with the wild-type genotype. A recent study found an association of the MC4R 103I variant with carbohydrate intake, which may mediate some of the association of this variant with leanness. Objective: The purpose of the study was to investigate the association between the MC4R V 103I polymorphism and the dietary intake of persons with severe obesity, which was derived by using the Willett food-frequency questionnaire. Design: The MC4R V103I polymorphism was genotyped in a group of 1029 severely obese white subjects with an average body mass index (BMI; in kg/m2) of 46.0 (range: 33-92). Results: Carriers of the 103I allele had significantly higher daily energy (364 kcal/d or 19%; P = 0.03) and carbohydrate (57 g/d or 27%; P = 0.01) intakes than did noncarriers, but there was no relation with BMI. No notable association of this polymorphism with lipid and glucose variables of the metabolic syndrome was observed. Conclusions: The higher dietary intake of carbohydrates in severely obese persons with the MC4R 103I variant is in line with previous findings. It may indicate a differential effect on body size measures in extremely obese subjects as compared with the general population. © 2008 American Society for Nutrition.