Genetic sensitivity to 6-N-propylthiouracil (PROP): Associations with food acceptance, intake, and body weight in preschool children

The ability to taste bitter thiourea compounds, such as 6-n-propylthiouracil (PROP), is inherited. Approximately 70% of US adults and children are PROP tasters and 30% are nontasters. PROP tasters are more sensitive to other bitter, sweet, hot, and fat tastes and often dislike strong tasting foods. Preliminary data have also linked PROP taste ability to lower body weights. No study has explored the relationship between PROP and the food habits of young children. In the following experiments, we classified a total of 120 preschool children as tasters or nontasters of PROP using a standard screening solution and measured acceptance of familiar foods with bitter, sweet, and fat taste qualities. Parents completed questionnaires to assess children's food preferences and intake at home. Children's anthropometric measures were taken in the laboratory. In the first 67 children, tasters gave lower liking ratings to raw broccoli and cheese (p ≤ 0.05). Girl nontasters gave higher liking scores to full-fat milk (p ≤ 0.05) and had higher parentally reported discretionary fat intakes (p ≤ 0.05).; The purpose of the follow-up investigation was to further investigate food preferences, intake, and body weight. Modifications were made to reflect information gathered from the first experiment. Children in the second study (N = 53) were significantly heavier (65% vs. 55% weight-for-height). In the laboratory, tasters of both genders disliked grapefruit-orange juice, while girl tasters gave higher ratings to sweetened cereals (p ≤ 0.05). In the second data set, boy nontasters had higher parentally reported discretionary fat consumption and higher weight-for-height percentiles than boy tasters (p ≤ 0.05), but these relationships were opposite for girls. Nontasters of both genders reported higher meat consumption, while tasters of both genders reported higher consumption of sweet-snacks (cookies, doughnuts, brownies, etc.). These data suggest relationships between PROP status and intake of certain high-fat food groups that differ as a function of taster status, gender, and possibly, complex PROP-gender interactions. Taste genetics interact with a multitude of environmental factors to influence eating behaviors and body weight in children. These experiments provide a valuable starting point for characterizing the nutritional significance of the PROP phenotype.