A Matter of Taste: How Genetics Shapes Our Food Preferences and Obesity Risk

Our perception of taste – sweet, sour, salty, bitter, and umami (savory), along with fat taste – is not uniform. Significant individual variation exists, driven in large part by genetic differences in the genes encoding taste receptors located on our tongues and throughout the digestive tract. These genetic variations can influence food preferences, dietary habits, and ultimately, contribute to obesity risk and metabolic health.

The Genetics of Basic Tastes

Sweet Taste: Primarily mediated by the TAS1R2/TAS1R3 receptor complex. Variations in these genes have been linked to differences in sweet taste sensitivity, preference for sugary foods and drinks, and potentially BMI or T2D risk.
Umami Taste: Also mediated by the TAS1R1/TAS1R3 complex. Variations may influence preference for savory, protein-rich foods.
Bitter Taste: Mediated by a large family of ~25 TAS2R receptors. Variations in TAS2R genes (most famously TAS2R38, responsible for detecting PTC/PROP bitterness) strongly influence sensitivity to bitter compounds found in many vegetables (e.g., cruciferous vegetables), potentially affecting their consumption. Reduced bitter sensitivity might paradoxically increase liking for some bitter alcoholic beverages or fatty foods.
Sour and Salty Taste: The genetic basis is less well understood compared to sweet, umami, and bitter, involving ion channels rather than G-protein coupled receptors. Variations likely contribute to differences in salt sensitivity and preference for sour foods.

Fat Taste Perception (Oleogustus)

Increasing evidence suggests humans can perceive the taste of non-esterified fatty acids (NEFAs), sometimes termed "oleogustus," mediated by receptors like CD36 and GPR120:

CD36 Variations: Polymorphisms in the CD36 gene have been linked to differences in oral fat detection thresholds, preference for high-fat foods, and potentially obesity risk and altered lipid metabolism. Individuals less sensitive to fat taste might consume more fatty foods before achieving satisfaction.
GPR120 Variations: Also implicated in fat taste signaling and linked to metabolic outcomes.

Impact on Food Preferences and Dietary Intake

Genetic variations in taste perception can translate into observable differences in eating behavior:

Vegetable Intake: Individuals highly sensitive to bitterness (e.g., TAS2R38 "supertasters") may consume fewer bitter green vegetables, potentially impacting micronutrient intake and overall diet quality.
Sweet Preference: Higher sensitivity or preference for sweetness might lead to greater consumption of sugary drinks and desserts, contributing to excess calorie intake.
Fat Preference: Lower sensitivity to fat taste might encourage higher intake of energy-dense fatty foods.
Compensatory Behaviors: Reduced sensitivity to one taste (e.g., sweetness) might lead individuals to seek out foods higher in other palatable components like fat or salt.

These preferences, established early in life (childhood obesity link), can track into adulthood.

Link to Obesity and Metabolic Health

While the link is complex and often moderated by environmental factors (food environment), taste genetics likely contribute to obesity risk:

Caloric Intake: Taste-driven preferences can influence overall energy intake.
Diet Quality: Aversion to bitter vegetables or preference for sweet/fatty foods can lead to less healthy dietary patterns.
Metabolic Signaling: Taste receptors are also found in the gut and pancreas, where they play roles in hormone secretion (e.g., GLP-1) and nutrient sensing (nutrient sensing pathways), potentially linking taste genetics directly to metabolic regulation beyond just food choice.

Nutrigenomic Implications

Personalized Dietary Guidance: Understanding an individual's taste genotype could help tailor dietary advice. For example, suggesting specific preparation methods (e.g., roasting) to reduce bitterness for TAS2R38 supertasters, or strategies to manage sweet cravings for those genetically predisposed. This aligns with broader personalized nutrition goals.
Explaining Variability: Taste genetics might help explain why some individuals struggle more than others to adhere to certain healthy eating patterns.
Product Development: Food industry could potentially use this knowledge to develop healthier products tailored to different taste profiles.

Conclusion

Our perception of taste is biologically determined, with genetics playing a significant role. These genetic variations influence our food preferences and dietary choices, contributing, alongside environmental factors, to our risk for obesity and metabolic disease. Incorporating taste genetics into nutrigenomic research provides a more complete understanding of eating behavior and opens possibilities for more nuanced and potentially effective personalized dietary strategies. However, it's crucial to avoid genetic determinism (ethical considerations) and recognize the powerful influence of environment and conscious choice.