Association of MAOA and COMT gene polymorphisms with palatable food intake in children

Several studies have implicated dopamine (DA) in appetite regulation. The enzymes catechol-o-methyltransferase (COMT) and monoamine oxidase A (MAOA) control DA availability and their genes have well-characterized functional variants. In this study, we examined three polymorphisms in these genes, T941G and MAOAu-VNTR in the MAOA gene and Val158Met in the COMT gene, to investigate how heritable variations in enzymes that determine DA levels might influence food intake and nutritional status. This investigation was a cross-sectional examination of 354 Brazilian children of three to four years old. Polymorphisms were analyzed by PCR-based methods. Means of dietary and anthropometric data were compared among genotypes by one-way analyses of variance or Kruskal Wallis tests. The MAOAu-VNTR and COMT Val158Met polymorphisms were associated with the amount of palatable food intake in boys. Presence of the MAOAu-VNTR⁎long allele was associated with higher intake of lipid-dense foods (LDF) when compared with the ⁎short allele (P=.009); the amount of sugar-dense foods (SDF) intake was also higher in males carriers of the MAOAu-VNTR⁎long allele than in carriers of the ⁎short allele (P=.034). In the girls' sample, MAOAu-VNTR polymorphism was not associated with food intake and nutritional status. Carriers of the COMT Val158Met⁎Val allele presented higher intake of LDF when compared with Met/Met homozygotes (P=.008). This study provides the first indication that genetic variants of enzymes that control DA availability might be involved in determination of the amount of palatable food intake in children.