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Keywords:

  • Bioavailability;
  • Caco-2;
  • Chlorogenic acid;
  • Interactions;
  • Milk proteins

Abstract

According to epidemiologic studies, dietary phenolic antioxidants, such as chlorogenic acid (CQA), could prevent coronary heart diseases and some cancers. Coffee is the main source of CQA in the human diet. The aim of this study was to assess the effect of usual coffee consumption conditions, such as the addition of milk, on CQA bioavailability. Interactions between CQA and milk proteins were shown, using an ultrafiltration technique. These interactions proved to be slightly disrupted during an in vitro digestion process. CQA absorption and bioavailability were then studied in vitro using a Caco-2 cell model coupled with an in vitro digestion process, and in vivo, in a chronic supplementation study in which rats were fed daily coffee or coffee and milk for 3 weeks. Both experiments showed that CQA absorption under its native form is weak, but unmodified by the addition of milk proteins, and slightly reduced by the addition of Maillard reaction products. These data show that there are some interactions between coffee phenolics and milk proteins, but these have no significant effect on CQA bioavailability from coffee in the rat. CQA is poorly absorbed under its native form in the body, when ingested in a realistic food matrix.