Researchers from Denmark found that antioxidants in coffee bind with milk proteins which may double the drink’s anti-inflammatory benefits.
Polyphenols are antioxidant compounds that help protect cells from damage. They are found in fruits, vegetables, and drinks, including coffee, tea, wine, and beer. You can also get concentrated doses of polyphenols from supplements.
However, the body does not easily absorb polyphenols, and few studies have examined what occurs when these antioxidants react with other molecules, such as proteins.
Previous studies by researchers from the Department of Food Science and the Department of Veterinary and Animal Sciences at the University of Copenhagen found that polyphenols bind to proteins in milk, meat, and beer. Still, the scientists weren’t sure if this binding action impacted how polyphenols work in the body.
For this study, published on January 30 in the Journal of Agricultural and Food Chemistry, the scientists investigated the anti-inflammatory effects of combining proteins with polyphenols. To conduct the study, the researchers induced artificial inflammation in immune cells. Then, they treated one group of cells with polyphenols that had reacted with an amino acid and another group with polyphenols alone. In addition, a third control group of cells did not receive either the polyphenols or polyphenol/amino acid combination.
The team discovered that immune cells treated with the amino acid/polyphenol combination were twice as effective at fighting inflammation than cells dosed with polyphenols alone.
The study authors note that they plan to explore these findings further using animal studies. Then, they hope to secure funding to continue investigating the effects in humans.
Testing this effect in coffee
Because coffee beans are rich in polyphenols and milk is rich in proteins, another new study tested whether the polyphenols bind to protein molecules when milk is added to coffee.
According to Professor Marianne Nissen Lund, from the Department of Food Science at the University of Copenhagen, Denmark, their results showed that reactions between polyphenols and proteins also occurred in coffee with milk.
Because of these results, the study authors suggest that drinking coffee with milk may offer better anti-inflammatory effects than consuming coffee without milk.
"I can imagine that something similar happens in, for example, a meat dish with vegetables or a smoothie, if you make sure to add some protein like milk or yogurt," Lund said in a news release.
She explained, "Because humans do not absorb that much polyphenol, many researchers are studying how to encapsulate polyphenols in protein structures which improve their absorption in the body. This strategy has the added advantage of enhancing the anti-inflammatory effects of polyphenols."
- Journal of Agricultural and Food Chemistry. Phenolic Acid–Amino Acid Adducts Exert Distinct Immunomodulatory Effects in Macrophages Compared to Parent Phenolic Acids.
- Food Chemistry. Covalent bonding between polyphenols and proteins: Synthesis of caffeic acid-cysteine and chlorogenic acid-cysteine adducts and their quantification in dairy beverages.
- University of Copenhagen. Coffee with milk may have an anti-inflammatory effect.