Oral and intestinal sweet and fat tasting: impact of receptor polymorphisms and dietary modulation for metabolic disease

The human body has evolved with a disposition for nutrient storage, allowing for periods of irregular food availability and famine. In contrast, the modern diet is characterized by excessive consumption of fats and sugars, resulting in a surge in the rates of obesity and type 2 diabetes. Although these metabolic disorders arise from a complex interaction of genetic, social, and environmental factors, evidence now points to fundamental changes in nutrient metabolism at the cellular level contributing to the underlying pathology. Taste receptors detect nutrients in the oral cavity and gastrointestinal tract and can influence the hormonal response to nutrients; they may also become maladaptive in conditions of excess fat or sugar consumption. Precise links between taste receptor activity, and downstream effects on energy intake and glycemia are not well defined. This review outlines the candidate taste receptors for carbohydrates and fats in the oral cavity and within the small intestine, highlighting the contributions of underlying genetics (polymorphisms) and sensory challenges (e.g., a high-fat diet) to the development of obesity and type 2 diabetes.