Aging modulates the effect of dietary glycemic index on gut microbiome composition in mice

Authors: ZHU, YING - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; YEO, EMILY - University Of Colorado; SMITH, KELSEY - Consultant; GREENBERG, ANDREW - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; ROWAN, SHELDON - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2024
Publication Date: 9/4/2024
Citation: Zhu, Y., Yeo, E.N., Smith, K.M., Greenberg, A., Rowan, S. 2024. Aging modulates the effect of dietary glycemic index on gut microbiome composition in mice. Journal of Nutrition. https://doi.org/10.1016/j.tjnut.2024.07.014.
DOI: https://doi.org/10.1016/j.tjnut.2024.07.014

Interpretive Summary: Diet and aging have distinct effects on gut microbiome composition, however, the interaction between diet and age has not been systematically studied. We used a mouse model to study the impact that dietary glycemic index has on mice that are young, middle-aged, or old. We found that the effect of diet on the gut microbiome was more profound in young mice than in old or middle-aged mice. We also identified specific kinds of gut bacteria that change with both age and diet.

Technical Abstract: Gut microbiome composition profoundly impacts host physiology and is modulated by several environmental factors, most prominently diet. The composition of gut microbiota change over the lifespan, particularly during the earliest and latest stages. However, we know less about diet-aging interactions on the gut microbiome. We previously showed that diets with different glycemic indices, based on the ratio of rapidly-digested amylopectin to slowly-digested amylose, led to altered composition of gut microbiota in C57BL/6J mice. Here, we examine the role of aging in influencing dietary effects on microbiota composition. We studied three age groups of mice: young (4 months), middle-aged (13.5 months), and old (22 months), all fed either high glycemic (HG) or low glycemic (LG) diets matched for caloric content and macronutrient composition. Young mice displayed lower alpha diversity scores than middle-aged counterparts but exhibited more pronounced differences in beta diversity between diets. In contrast, old mice had slightly lower alpha diversity scores than middle-aged mice, with significantly higher beta diversity distances. Within-group variance was lowest in young, LG-fed mice and highest in old, HG-fed mice. Differential abundance analysis revealed taxa associated with both aging and diet. Most differential taxa demonstrated significant interactions between diet and aging. Notably, several members of the Lachnospiraceae family increased with aging and HG diet, while taxa from the Bacteroides_H genus increased with the LG diet. Akkermansia muciniphila decreased with aging. These findings illustrate the complex interplay between diet and aging in shaping the gut microbiota, potentially contributing to age-related disease.