Interaction between grape seed polyphenols and dairy-based bacteria: implications for vascular health

Abstract

We have previously demonstrated that 2 g/d of grape seed extract (GSE) in yogurt with viable bacteria improves blood vessel function, but could not confirm this with a similar doses of GSE in cordial, either chronically or acutely. We hypothesised that this may be due to metabolism of the GSE by the yogurt bacteria into phenolics acids. We showed that GSE in yogurt produced lower levels of intact catechins that GSE in cordial, but higher levels of an important metabolite of the catechins 4-ortho methoxy gallic acid. We also showed that GSE in yogurt had a beneficial effect on vascular function over the first four hours after consumption, compared with cordial or milk, suggesting bacterial metabolism of GSE was important.