Dietary proanthocyanidins for improving gut immune health

Proanthocyanidins (PACs) are bioactive polyphenols with varying distribution in plants. Most dietary PACs are highly polymerized with limited absorption in the gastrointestinal tract. However, emerging evidence highlights that incorporating PACs into the diet enhances immune function through gut-mediated mechanisms. These include modulating gut microbiota, inhibiting microbes, dampening immunocytes and inflammatory pathways, improving gut barrier function, and enhancing antioxidant activity. Nevertheless, further research is needed to determine the structure–function relationships of PACs with these potential immune benefits. Additional human intervention studies are needed to clarify the dose–response and mechanisms responsible for improving health. Addressing these gaps will aid in developing specific dietary recommendations for PACs to enhance gut immune health and reduce chronic disease risk.