Nestlé Research Center, Nestec Ltd, Lausanne, Switzerland.
Mol Nutr Food Res. 2014 Feb;58(2):301-9. doi: 10.1002/mnfr.201300349. Epub 2013 Sep 4.
Coffee contains phenolic compounds, mainly chlorogenic acids (CGAs). Even though coffee intake has been associated with some health benefits in epidemiological studies, the bioavailability of coffee phenolics is not fully understood.
We performed a dose-response study measuring plasma bioavailability of phenolics after drinking three increasing, but still nutritionally relevant doses of instant pure soluble coffee. The study design was a one treatment (coffee) three-dose randomized cross-over design, with a washout period of 2 wks between visits.
CGAs, phenolic acids, and late-appearing metabolites all increased with increasing ingested dose. Hence, the sum of area under the curve was significantly higher for the medium to low dose, and high to medium dose, by 2.23- and 2.38-fold, respectively. CGAs were not well absorbed in their intact form, regardless of the dose. CGA and phenolic acids appeared rapidly in plasma, indicating an early absorption in the gastrointestinal tract. Late-appearing metabolites were the most abundant, regardless of the dose.
This study confirmed previous findings about coffee bioavailability but also showed that coffee phenolics appear in a positive dose-response manner in plasma when drank at nutritionally relevant doses.
咖啡含有酚类化合物，主要是绿原酸（CGAs）。尽管在流行病学研究中，咖啡的摄入与一些健康益处有关，但咖啡酚类的生物利用度还不完全清楚。
我们进行了一项剂量反应研究，测量了饮用三种递增但仍具有营养相关性的速溶纯咖啡剂量后，酚类物质在血浆中的生物利用度。研究设计为一种处理（咖啡）三种剂量随机交叉设计，两次就诊之间有 2 周的洗脱期。
随着摄入剂量的增加，CGAs、酚酸和后期出现的代谢物均增加。因此，中低剂量和高到中剂量的曲线下面积总和分别显著增加了 2.23 倍和 2.38 倍。无论剂量如何，CGAs 都不能以完整的形式被很好地吸收。CGA 和酚酸迅速出现在血浆中，表明在胃肠道中有早期吸收。无论剂量如何，后期出现的代谢物都是最丰富的。
这项研究证实了以前关于咖啡生物利用度的发现，但也表明，当以营养相关剂量饮用时，咖啡酚类物质在血浆中呈现出正剂量反应方式。
