Resistant Potato Starch Supplementation Increases Serum Antioxidant Levels in a Randomized Trial

Background/Objectives: The prebiotic effect of resistant potato starch (RPS) has been demonstrated, but the antioxidant properties associated with this ingredient have not been explored. Methods: We performed post hoc analysis of serum metabolomic data from a clinical trial evaluating 3.5 g RPS per day consumption (n = 24) versus a placebo (n = 24) for 4 weeks in a randomized clinical trial (NCT05242913). Results: Levels of the exogenous antioxidants all-trans retinol and α-tocopherol increased in the RPS-consuming group. Among endogenous antioxidants, the concentration of coenzyme Q10 (CoQ10) increased in both treatment groups, while uric acid was unaffected. Hippuric acid, a marker of polyphenol metabolism, was unaffected by treatment, as was the abundance of the tryptophan metabolites kynurenine and 3-hydroxyanthranillic acid. However, levels of 3-hydroxykynurenine were decreased in both treatment groups. Levels of the advanced glycation end products NƐ-(1-carboxymethyl)-L-lysine and NƐ-(1-carboxyethyl)-L-lysine, markers of chronically elevated oxidative stress, were unaffected by treatment. Notably, increases in serum all-trans retinol were correlated with increases in Akkermansia. Conclusions: RPS enhances the absorption of antioxidants all-trans retinol and α-tocopherol from the diet and also influences CoQ10 levels and tryptophan metabolism. Future studies assessing the physiological consequences of enhanced antioxidant absorption in people consuming RPS over a longer duration are warranted.