Genetic sensitivity to the bitter taste of 6-n-propylthiouracil (PROP) and its association with physiological mechanisms controlling body mass index (BMI).

Beverly J Tepper,Iole Tomassini Barbarossa,Roberto Crnjar,Sebastiano Banni,Melania Melis

doi:10.3390/nu6093363

Beverly J Tepper, Iole Tomassini Barbarossa + Show 3 more

Open Access

https://doi.org/10.3390/nu6093363

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Journal: Nutrients	Publication Date: Aug 27, 2014
Citations: 226	License type: CC BY 4.0

Affiliation: University of Cagliari

Abstract

Taste sensitivity to the bitter compound 6-n-propylthiouracil (PROP) is considered a marker for individual differences in taste perception that may influence food preferences and eating behavior, and thereby energy metabolism. This review describes genetic factors that may contribute to PROP sensitivity including: (1) the variants of the TAS2R38 bitter receptor with their different affinities for the stimulus; (2) the gene that controls the gustin protein that acts as a salivary trophic factor for fungiform taste papillae; and (3) other specific salivary proteins that could be involved in facilitating the binding of the PROP molecule with its receptor. In addition, we speculate on the influence of taste sensitivity on energy metabolism, possibly via modulation of the endocannabinoid system, and its possible role in regulating body composition homeostasis.

Highlights

Taste is the sensory modality that enables organisms to distinguish nutrient-rich food from noxious substances, and acts as a final checkpoint for food acceptance or rejection behavior [1,2]
We studied a homogenous genetic cohort on the island of Sardinia and showed that a key factor strongly associated with PROP taste sensitivity is the polymorphism, rs2274333 (A/G), located in the gustin (CA6) gene that controls the zinc-dependent salivary protein of the same name [53,71]
Recent discoveries elucidating the role of PROP and other taste phenotypes, such as gustin, in body weight provide critical insights for understanding the influence of taste sensitivity on eating behavior, energy metabolism, BMI and health

Summary

Introduction

Taste is the sensory modality that enables organisms to distinguish nutrient-rich food from noxious substances, and acts as a final checkpoint for food acceptance or rejection behavior [1,2]. Digestive enzymes such as amylase and lipases are present in saliva that degrade macronutrients into these single units [15] These molecules can interact through a variety of oral sensing mechanisms to convey signals about the quantity and quality of the ingested nutrients contributing to the efficient metabolism and disposal of such nutrients. It would be crucial for this system to respond to danger by sensing the presence of excess free fatty acids or amino acids that may indicate the presence of food degradation or contamination by hydrolytic microorganisms. Understanding the range of oral sensibilities in human beings and how it is influenced by genetic and environmental variables may lead to important insights about the role of taste in food intake regulation and metabolism

Physiological Overview of Taste Sensitivity

Genetic Factors Contributing to PROP Sensitivity

Nutritional Implications of PROP Bitter Taste Sensitivity

Findings

Conclusions