# Associations between food consumption with T cell activation and antibody responses following SARS-CoV-2 mRNA vaccination

## TL;DR

This study finds that eating yogurt and bread regularly is linked to stronger immune responses after receiving an mRNA vaccine for SARS-CoV-2.

## Contribution

The study identifies specific dietary items associated with enhanced immune responses to SARS-CoV-2 vaccination, suggesting a potential role of diet in vaccine effectiveness.

## Key findings

- Yogurt and bread consumption correlated with higher CD4+ T cell activation and antibody levels after vaccination.
- Higher yogurt and bread consumption was associated with stronger immune responses even after adjusting for age, sex, and vaccination history.
- Serum and fecal antibodies correlated, with gut microbiota and metabolites possibly influencing immune responses.

## Abstract

COVID-19 mRNA vaccines induce protective immunity, but the factors influencing individual immune responses remain incompletely understood. This study investigated associations between dietary habits, T cell activation, and antibody responses to SARS-CoV-2 vaccination. We analyzed peripheral blood mononuclear cells following spike protein stimulation and measured anti-SARS-CoV-2 S protein antibody levels. We found significant positive correlations between CD4+ activation-induced marker (AIM)+ T cells, CD4+ CD69+ T cells, and anti-SARS-CoV-2 S protein antibody levels. Among various food items, yogurt and bread consumption frequencies showed significant positive correlations with immune parameters. Participants with high yogurt consumption (daily or more) demonstrated significantly higher levels of CD4+ AIM+ T cells, CD4+ CD69+ T cells, and antibody levels compared to low consumption groups. Similar patterns were observed for bread consumption. These associations remained significant after adjusting for age, sex, vaccination count, and prior infection history. Additionally, we observed correlations between serum and fecal anti-SARS-CoV-2 antibodies, with distinct gut microbiota and metabolite profiles associated with antibody levels. Our findings suggest that regular consumption of specific foods may influence vaccine-induced immune responses, potentially through interactions with the gut environment. These results provide a foundation for investigating dietary approaches to optimize vaccine responses.