How ketogenic and vegan diets shape host immunity and gut microbial functions

Link V, Subramanian P, Cheung F, et al. Differential peripheral immune signatures elicited by vegan versus ketogenic diets in humans. Nat Med 2024; 302: 560–572. doi: 10.1038/s41591-023-02761-2.

Nutritional intervention has therapeutic potential against diseases directly or via the gut microbiota. However, the link between nutrition and the host immunity remains largely unknown. Link et al applied a multiomics approach including flow cytometry, transcriptomic, proteomic, metabolomic and metagenomic analysis to collectively access the effect of diet and dietary switch on host immunity and gut microbiota. A group of 40 participants admitted to the study were divided into two groups, and provided with a 2-week ketogenic diet and a 2-week vegan diet on a different order. RNA sequencing of whole blood and flow cytometry analysis on peripheral blood mononuclear cells has revealed a change, independent of dietary order, in host immunity following nutritional intervention. The ketogenic diet resulted in an upregulation of pathways linked to adaptive immunity driven by B cells and T cells, and a vegan diet upregulated pathways associated with innate immunity driven by neutrophils. Plasma transcriptomic profile together with the proteosome showed an enrichment in erythropoiesis and heme metabolism following the vegan diet. While nutritional intervention altered the composition of the gut microbiota, numerous microbial pathways were downregulated following the ketogenic diet, especially in biosynthesis of amino acid and vitamins. As an increased host amino acid metabolism revealed by the targeted metabolomics on plasma samples following the ketogenic diet, it suggested a reduced host reliance on microbial biosynthesis when the availability of dietary amino acid is high. Interestingly, dietary order had no impact on the host immunity or functions of gut microbiota. In summary, this study highlighted the potential of dietary intervention in disease mitigation.

A novel biomarker for atezolizumab–bevacizumab response in hepatocellular carcinoma

Zeng Q, Klein C, Caruso S, et al. Artificial intelligence-based pathology as …