The Human Sweet Tooth

Humans love the taste of sugar and the word "sweet" is used to describe not only this basic taste quality but also something that is desirable or pleasurable, e.g., la dolce vita. Although sugar or sweetened foods are generally among the most preferred choices, not everyone likes sugar, especially at high concentrations. The focus of my group's research is to understand why some people have a sweet tooth and others do not. We have used genetic and molecular techniques in humans, rats, mice, cats and primates to understand the origins of sweet taste perception. Our studies demonstrate that there are two sweet receptor genes (TAS1R2 and TAS1R3), and alleles of one of the two genes predict the avidity with which some mammals drink sweet solutions. We also find a relationship between sweet and bitter perception. Children who are genetically more sensitive to bitter compounds report that very sweet solutions are more pleasant and they prefer sweet carbonated beverages more than milk, relative to less bitter-sensitive peers. Overall, people differ in their ability to perceive the basic tastes, and particular constellations of genes and experience may drive some people, but not others, toward a caries-inducing sweet diet. Future studies will be designed to understand how a genetic preference for sweet food and drink might contribute to the development of dental caries

Short-Term Pilot Study of the Effect of Sleeve Gastrectomy on Food Preference

The effect of vertical sleeve gastrectomy (VSG) on food preference has not been examined in humans, but VSG decreases preference for fat and calorically dense foods in rodents. A validated Food Preference Questionnaire (FPQ) assessed food preference changes before and 6-weeks after VSG in humans. The FPQ was completed before and 43 ± 19 days (Mean ± SD) after VSG. Fifteen subjects (14 females) completed the study. Hedonic ratings decreased for foods high in fat and sugar (p = 0.002) and high in fat and complex carbohydrate (p = 0.007). Fat preference (p = 0.048) decreased, VSG reduced preference for calorically dense foods high in fat, sugar and complex carbohydrate, and these changes may contribute to the weight loss with VSG

Assessing established BMI variants for a role in nighttime eating behavior in robustly phenotyped Southwestern American Indians

BACKGROUND/OBJECTIVES: Nighttime eating (NE) behavior has a genetic component and predicts weight gain. We hypothesized that some genetic variants, which affect NE would also show an effect on body mass index (BMI). We aimed to determine which known BMI variants associate with NE in Southwestern American Indians (SWAIs), who are at elevated risk for obesity. METHODS: Known BMI variants from the GIANT-UK Biobank meta-analysis (N = 700,000) were analysed in SWAIs characterized for NE during an inpatient 3-day protocol. Variants were analysed for association with NE using whole-genome sequence data from 50 SWAIs (23 cases and 27 controls) and selected variants were genotyped in an additional 32 SWAIs (13 NE cases and 19 controls). Variants associated with NE in a meta-analysis of the two SWAI samples were further analysed for association with nightly caloric intake and functionality in hypothalamus, pituitary, and adrenal tissues. RESULTS: Variants were identified where the allele that associated with increased BMI in the GIANT-UK Biobank meta-analysis (P ≤ 1 × 10-8) also had a P < 0.01 for increased NE in the SWAI meta-analysis. These variants were captured by six tagSNPs. Comparison of the nightly calorie intake by genotype and eQTL data from relevant tissues highlighted rs3753612 upstream of HCRTR1. CONCLUSIONS: Our strategy led to the HCRTR1 locus, which has previously been linked to sleep regulation and feeding. Although this is an intriguing candidate gene for NE, further studies in larger samples and different populations are required to validate the role of HCRTR1 in NE