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This study examined how quickly the gut microbiome and immune system respond when mice switch between standard and Western diets after 8 weeks of initial feeding. Researchers found that gut bacterial communities restructured within two weeks of diet switching, but microbial metabolic outputs (short-chain fatty acids) changed more slowly and some bacterial populations retained signatures of the previous diet. Immune system changes occurred progressively, with activation markers responding rapidly to diet changes while memory and regulatory immune cells maintained longer-lasting imprints from prior dietary exposure.
Why it matters
The findings suggest that short-term dietary interventions can quickly alter gut bacteria and certain immune responses, but complete reversal of diet-induced changes requires longer periods. This has implications for understanding how dietary modifications might be used therapeutically to improve metabolic and immune health in individuals with poor long-term dietary habits.
Understand the Science
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Diet is a major determinant of the gut microbiome and immune homeostasis, yet the extent to which short-term dietary interventions can remodel established microbial communities and reprogramme immune phenotypes following long-term western diet consumption remains poorly understood. Here, we investigated temporal dynamics of the gut microbiome, microbial metabolites, intestinal barrier function and local and systemic immune responses following diet switching. Mice were fed either a standard chow or a western diet for 8 weeks before remaining on these diets or switching to the alternate diet for 2 or 4 weeks. Long term consumption of chow and western diets resulted in distinct gut microbial communities and differences in intestinal permeability. Diet switching rapidly remodelled microbial community structure within two weeks, with substantial bidirectional changes in community composition. Despite these changes, the relative abundance of several taxa remained influenced by prior dietary exposure. In contrast, faecal SCFA profiles remained largely associated with long-term diet, indicating that microbial metabolic outputs were altered more slowly than microbial community composition. Mass cytometry revealed progressive remodelling of local (MLN) and systemic (PBMC and spleen) immune responses following dietary switching. Activation-associated immune phenotypes, including Ki67+ and PD-1+ B and T cells, inflammatory monocytes and ROR{gamma}t+ regulatory T cells, rapidly responded to diet switching, whereas overall B cells, regulatory T cells and effector memory T cells retained signatures of long-term dietary exposure. Together, these findings demonstrate distinct temporal dynamics across the diet-microbiome-immune axis, whereby gut microbial composition and immune activation states remain highly plastic, while microbial metabolic outputs and several memory and regulatory immune phenotypes exhibit persistent dietary imprinting. These findings highlight the potential utility of short-term dietary interventions to modulate host-microbiome interactions and immune homeostasis.