Coffee is a source of inflammation-fighting antioxidants. Now a new study suggests that adding a dash of milk that contains protein can boost the health benefits of your cup of coffee.
Researchers from the University of Copenhagen in Denmark examined how antioxidants called polyphenols interacted with amino acids, the building blocks of proteins, and found that combining them has twice the effect on fighting cellular inflammation as polyphenols alone.
Polyphenols can be found in many foods, including coffee and tea, fruits and vegetables, red wine, and beer. Like other antioxidants, past studies suggest some polyphenols can prevent and slow the oxidation of healthy chemicals and protect our bodies from disease.
They are thought to do this in part by controlling inflammation, a complex immune response involving cells called macrophages that release several inflammatory mediators. Inflammation helps protect against infection, but if it isn't controlled properly, it can lead to diseases like type II diabetes, Alzheimer's, and Parkinson's.
多酚通过抑制炎症实现部分抗氧化作用，炎症是一种复杂的免疫反应，是巨噬细胞释放多种炎症介质引起的。炎症有助于防止感染，但如果控制不当，可能会导致 II 型糖尿病、阿尔茨海默病和帕金森病等疾病。
Caffeic acid (CA) and chlorogenic acid (CGA) are polyphenols that are well known to have antioxidant and anti-inflammatory effects, but the authors wanted to find out if reactions that these polyphenols have with other chemicals can further affect immune regulation.
咖啡酸 (CA) 和绿原酸 (CGA) 是公认的多酚类物质，具有抗氧化和抗炎作用。研究人员希望弄清这些多酚类物质与其他化合物的反应是否会进一步影响免疫调节。
Adducts are products that are made when two or more molecules come together. In this case, the amino acid cysteine (Cys) – found in milk products – was combined with the polyphenols CA and CGA – found in coffee – to make the adducts CA–Cys and CGA–Cys.
加合物是当两个或多个分子聚集在一起时产生的产物。在这种情况下，奶制品中的氨基酸半胱氨酸（Cys）与咖啡中的CA和CGA结合，形成加合物 CA–Cys 和 CGA–Cys。
To support this research, the authors successfully showed in another new study that polyphenols bind to proteins in a coffee drink with milk.
"Our result demonstrates that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that we studied. In fact, the reaction happens so quickly that it has been difficult to avoid in any of the foods that we've studied so far," says food scientist and co-author on both studies, Marianne Nissen Lund.
In this study, the researchers used RNA-sequencing to study the immune-regulating effects of CA–Cys and CGA–Cys in macrophage cells subjected to artificial inflammation.
在这项研究中，研究人员使用 RNA 测序来分析 CA–Cys 和 CGA–Cys 在有炎症的巨噬细胞中的免疫调节作用。
They also tested the effects of CA and CGA alone and compared them to a control group of macrophages not exposed to the polyphenols or the Cys adducts.
他们还单独测试了 CA 和 CGA 的作用，并将它们与未暴露于多酚或 Cys 加合物的巨噬细胞对照组进行了比较。
As they expected, the polyphenols CA and CGA inhibited inflammatory responses, in particular the production of reactive oxygen species (ROS), prostaglandin E2 (PGE2), and the cytokines interleukin-6 and tumor necrosis factor (TNF).
正如预期那样，多酚 CA 和 CGA 抑制了炎症反应，特别是活性氧 (ROS)、前列腺素 E2 (PGE2) 以及细胞因子白细胞介素 6 和肿瘤坏死因子 (TNF) 的产生。
But when polyphenols CA and CGA were combined with amino acid cysteines found in milk proteins, their anti-inflammatory effects received a boost.
Macrophage cells exposed to polyphenols on their own, for instance, showed more than 2.5 times as much TNF activity as they did in the face of a polyphenols-cysteine adduct.
例如，暴露于多酚中的巨噬细胞表现出的 TNF 活性是其暴露于多酚-半胱氨酸加合物时的 2.5 倍以上。
The only exception was ROS, which inexplicably increased in the macrophage when the polyphenol-amino acid combo was present compared to when the polyphenol was on its own.
"It is interesting to have now observed the anti-inflammatory effect in cell experiments. So, the next step will be to study the effects in animals," says immunologist and senior author Andrew Williams.
Further research is needed to figure out why and what these results mean practically for human health. This study only examined how a single type of immune mediator reacts to coffee-like chemicals in a laboratory setting.
"Our results can be used as an important reference in applications of adducts formed from phenolic compounds and amino acids in future functional food or medicinal products that aim to modulate metabolic, neurological, or immune-related diseases," the researchers conclude in their paper.
The research has been published in the Journal of Agricultural and Food Chemistry.