Milk exosomes show promise in boosting ellagic acid absorption and gut health

A team led by researchers at CEBAS-CSIC are exploring an innovative way to enhance the effectiveness of dietary compounds using tiny biological packages called extracellular vesicles (EVs), specifically milk-derived exosomes (EXOs). Their focus? Ellagic acid (EA), a natural antioxidant found in foods like pomegranates and berries, which typically has poor bioavailability when taken by mouth.

In this study, the researchers encapsulated ellagic acid inside milk exosomes (creating what they call EXO-EA) and administered them to mice and rats to see if this approach would improve how much EA the body could absorb and whether it would affect gut bacteria. The results were mixed.

(A) Experimental design for the plasma and brain kinetic disposition study in rats. (B) Experimental design for the oral bioavailability study in mice. At the end of each study, blood samples and perfused organs (brain, liver, ovaries, or prostate, depending on the study) were collected and analyzed by UPLC-qTOF-MS.

In rats, intravenous delivery of EXO-EA resulted in a dramatic increase, four times higher, in ellagic acid levels in the blood, with detectable amounts even reaching the brain. This indicates that exosomes may be effective carriers for systemic delivery of EA when administered directly into the bloodstream.

However, when EXO-EA was given orally to mice, the protective exosome coating couldn’t withstand digestion in the gastrointestinal tract, and no significant increase in systemic EA levels was observed. Despite this limitation, EXO-EA did have an impact in the gut, especially in male mice. The male group showed increased production of beneficial compounds like urolithin A and short-chain fatty acids (SCFAs), along with a more favorable gut microbiota composition, including bacteria associated with gut health like Christensenellaceae and Ruminococcus. In female mice, both EXO-EA and regular EA increased the abundance of bifidobacteria, beneficial microbes often found in probiotics.

The study highlights that while milk exosomes have potential as natural delivery systems for bioactive compounds like ellagic acid, challenges such as digestive stability and encapsulation efficiency must be addressed before this strategy can be used effectively for oral therapies. Notably, the research also emphasizes that biological sex may influence how individuals respond to such interventions—an important consideration for future personalized nutrition strategies.