Energy and macronutrient intake heritability: a systematic review and meta-analysis of twin and family-based studies

Background /Aims: The current meta-analysis aimed to examine the heritability and familial resemblance of dietary intakes, including energy and macronutrients in both twin and family-based studies. Methods The online literature databases, including PubMed, Scopus, and Web of Science were searched comprehensively until 2023 to identify the relevant studies. The heritability index in family studies was h2 and the heritability indices for twin studies were h2, A2, and E2. Three weighted methods were used to calculate the mean and SE of heritability dietary intakes. Results Eighteen papers including 8 studies on familial population and 12 for twin population studies were included in the present meta-analysis. The heritability of dietary intakes in twin studies(range of pooled estimated h2, A2, and E2 was 30-55%, 14-42%, and 52-79%, respectively) was higher than family studies (range of pooled estimated h2= 16-39%). In family studies, the highest and lowest heritability for various nutrients was observed for the fat (%Kcal)(h2 range:36-38%) and carbohydrate in g(h2 range:16-18%), respectively. In twin studies, based on mean h2, the highest and lowest heritability for various nutrients was reported for the fat (%Kcal)(h2 range:49-55%) and protein intake in g(h2 range:30-35%), respectively. Also, based on the mean of A2, the highest and lowest heritability was observed for carbohydrates(% Kcal) (A2 range:42-42%), and protein(% Kcal)(A2 range:14-16%), respectively. Furthermore, in twin studies, the highest and lowest mean of E2 was shown for saturated fats(E2 range:74-79%) and energy intake (E2 range:52-57%), respectively. Conclusion Our analysis indicated that both environmental factors and genetics have remarkable contributions in determining the heritability of dietary intakes. Also, we observed higher heritability in twins compared to family studies.