Understanding the determinants of sweet taste liking in the African and East Asian ancestry groups in the U.S.-A study protocol

Abstract

Background: The liking for sweet taste is a powerful driver for consuming added sugars, and therefore, understanding how sweet liking is formed is a critical step in devising strategies to lower added sugars consumption. However, current research on the influence of genetic and environmental factors on sweet liking is mostly based on research conducted with individuals of European ancestry. Whether these results can be generalized to people of other ancestry groups warrants investigation.

Methods: We will determine the differences in allele frequencies in sweet-related genetic variants and their effects on sweet liking in 426 adults of either African or East Asian ancestry, who have the highest and lowest average added sugars intake, respectively, among ancestry groups in the U.S. We will collect information on participants' sweet-liking phenotype, added sugars intake (sweetness exposure), anthropometric measures, place-of-birth, and for immigrants, duration of time living in the U.S. and age when immigrated. Ancestry-specific polygenic scores of sweet liking will be computed based on the effect sizes of the sweet-related genetic variants on the sweet-liking phenotype for each ancestry group. The predictive validity of the polygenic scores will be tested using individuals of African and East Asian ancestry from the UK Biobank. We will also compare sweet liking between U.S.-born individuals and immigrants within each ancestry group to test whether differences in environmental sweetness exposure during childhood affect sweet liking in adulthood.

Discussion: Expanding genetic research on taste to individuals from ancestry groups traditionally underrepresented in such research is consistent with equity goals in sensory and nutrition science. Findings from this study will help in the development of a more personalized nutrition approach for diverse populations.

Trial registration: This protocol has been preregistered with the Center for Open Science (https://doi.org/10.17605/OSF.IO/WPR9E).

Fig 1. Study design flowchart.

Fig 2. Test-retest reliability of the Simple Sweet Test between 2 different test days.

Individual sweet liking scores were calculated using the slopes of the degree of the average liking for the 0.09 M and 1.05 M solutions for each participant. (A) the test-retest reliability of all participants. (B) the test-retest reliability of the African ancestry group. (C) the test-retest reliability of the East Asian ancestry group. The number on the plot represents participant IDs.

Fig 3. Distribution of the sweet liking score assessed using the Simple Sweet Test.

Individual sweet liking scores were calculated using the slopes of the degree of the average liking for the 0.09 M and 1.05 M solutions for each participant.