The inhibitory effect of milk on the absorption of dietary phenolic acids and the change in human plasma antioxidant capacity through a mechanism involving both milk proteins and fats

Authors


Correspondence: Dr. Fazheng Ren, College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 287, No. 17 Qinghua East Road, Haidian, Beijing 100083, P. R. China

E-mail: renfazheng@263.net

Fax: +86-10-62736344

Abstract

Scope

We assessed the effects of milk proteins and fats, alone and in combination, on the absorption of phenolic acids and the change in plasma antioxidant capacity after jujube juice intake in humans.

Methods and results

Twenty volunteers received the following four treatments each in a 4 × 4 Latin square design with a minimum 1 week interval: 200 mL of jujube juice plus 200 mL of (1) water; (2) whole milk; (3) skimmed milk; or (4) milk fat. The results showed that skimmed milk extended the time to reach maximum increase of plasma phenolic acids concentrations and plasma antioxidant capacity. However, neither the skimmed milk nor the milk fat had a significant effect on the absorption of phenolic acids. In contrast, whole milk significantly reduced the absorption of phenolic acids and the increase in plasma antioxidant capacity (p < 0.05). In vitro results suggested the formation of complexes during digestion that involved milk proteins, milk fats, and phenolic acids, which were responsible for the inhibitory effect of whole milk.

Conclusion

Milk proteins and fats together, but not alone, are responsible for the inhibitory effect of milk on the absorption of phenolic acids and the change in plasma antioxidant capacity.

Ancillary