Genetic influences on diet in young Swedish adults: a twin study

Dietary choices are shaped by both genetic predisposition and environmental exposures, yet the relative influence of these factors remains insufficiently understood across populations and age groups. Young adulthood represents a critical period when long-term eating habits take form, and clarifying the determinants of dietary behavior in this life stage may inform strategies to promote sustained health.

This twin study aimed to estimate genetic and environmental contributions to food, energy, and nutrient intakes, and taste preferences in young adults in Sweden.

The study included 2832 Swedish twins (858 monozygotic and 1974 dizygotic; mean age 24 y; 59.5% female). Participants completed a validated dietary questionnaire assessing food intake frequencies and taste preferences. Additive genetic (A), shared environmental (C), and nonshared environmental (E) influences on a priori dietary indices, specific food and nutrient intakes, and taste preferences were estimated using classical ACE twin models and nested models fitted in OpenMx.

Heritability estimates across dietary traits ranged from 20% to 61%. Genetic influences on overall dietary pattern indices exceeded 40%. Heritability varied across food groups (e.g., 61% for venison; 24% for potatoes) and nutrient intakes (50% for fiber; 20% for sodium), indicating differing degrees of genetic impact across dietary components. Taste preferences also showed substantial genetic contributions (21%-61%), with the strongest effects observed for bitter foods (e.g., black coffee, grapefruit), followed by sweet foods (e.g., jam/marmalade).

This large-scale twin study provides a comprehensive overview of genetic and environmental influences on dietary behavior in young adults, showing substantial genetic and nonshared environmental contributions across diverse dietary traits. These results provide a foundation for future research on diet-disease relationships and may support the development of prevention and intervention strategies, including emerging precision-nutrition approaches.