Genetic ancestry in relation to the metabolic response to a US versus traditional Mexican diet: a randomized crossover feeding trial among women of Mexican descent.

Abstract

BackgroundCertain populations with a large proportion of Indigenous American (IA) genetic ancestry may be evolutionarily adapted to traditional diets high in legumes and complex carbohydrates, and may have a detrimental metabolic response to U.S. diets high in refined carbohydrates and added sugars. We tested whether IA ancestry modified the metabolic response to a U.S. versus traditional Mexican diet in a controlled dietary intervention.MethodsFirst and second generation Mexican immigrant women (n=53) completed a randomized crossover feeding trial testing the effects of a U.S. versus traditional Mexican diet. The metabolic response to the diets was measured by fasting serum concentrations of glucose, insulin, IGF-1, IGFBP-3, adiponectin, CRP, IL-6, and computed HOMAIR. Blood collected at baseline was used for genotyping and estimation of African, European, and IA ancestries with the use of 214 Ancestry Informative Markers.ResultsThe genetic ancestral background was 56% IA, 38% European, and 6% African. Women in the highest IA ancestry tertile (>62%) were shorter in height, less educated and less acculturated to the U.S. lifestyle, and tended to have higher waist-to-hip ratio compared to women in the middle and lowest IA ancestry tertiles, respectively. Compared to the U.S. diet, the traditional Mexican diet tended to reduce glucose, insulin, IGF-1, IGFBP-3, and HOMAIR among women in the middle IA ancestry group (IA ancestry ≤45–62%); while having no effect on biomarkers related to inflammation.ConclusionsWe observed modest interactions between IA ancestry and the metabolic response to a U.S. versus traditional Mexican diet among Mexican immigrant women.