Implications of adding milk on the beneficial properties of coffee

Coffee is the third most consumed beverage worldwide, only after water and tea. Through its different presentations, it is consumed by around 80-90% of the adult population. In addition to its economic, social, and cultural importance, several studies have proven the positive effects of its consumption.

Among the most important benefits of coffee are its capacity to activate a state of mental alertness (which we need so much at the beginning of the week), as well as its effects on the prevention of neurological diseases such as Parkinson's, diabetes, and metabolic syndrome, in addition to its favorable effects on the health of the liver.

These properties are mainly attributed to its content of antioxidants such as phenolic compounds, caffeine, and melanoidins. Among the most studied compounds in coffee are phenolics such as those derived from chlorogenic acid (5-dicaffeoylquinic, 4-caffeoylquinic, and 3-caffeoylquinic phenolic acids, among others).

An interesting and curious fact is that, although green tea is the most consumed beverage in the world, coffee exceeds its total polyphenol content (approximately 480 vs. 276 mg per cup, respectively).

Likewise, the concentration of polyphenols in coffee can vary depending on the type of coffee (arabica or robusta), the roasting, and the way it is prepared (coffee maker, instant, French press), etcetera.

Did you know that the simple fact of adding cream or milk to your coffee could somehow affect the antioxidant content of the coffee?

Although beverages such as latte or macchiato, which are prepared with milk and milk foam, are very popular for their attractive flavor, some studies have shown that both the content of phenolic compounds and the antioxidant capacity of coffee is affected when milk is added.

Apart from the dilution effect, this may be because the antioxidant compounds in coffee interact with the milk proteins, resulting in the formation of protein-phenolic complexes. This same effect is observed when milk is added to infusions such as green tea.

On the other hand, the addition of milk has been a controversial issue in some studies, since some researchers suggest that the formation of complexes between milk proteins and coffee antioxidants can decrease the absorption of the latter, while other authors mention that there is no negative effect.

However, although the studies are not conclusive, some reports mention that the amount of milk added could be one of the important factors in this phenomenon, since it has been demonstrated that low amounts of milk do not interfere with the absorption of the phenolic antioxidants of coffee.

This could suggest that coffee, in its different forms, could provide different amounts of antioxidants to the body, since coffee without milk is the one that provides the highest amount of caffeoylquinic acids.

Finally, the decision of how to ingest coffee is up to the consumer, which is surely more influenced by the flavor and aromas. We hope that this information is useful for you to make decisions in which you can take maximum advantage of the antioxidants in beverages such as coffee.

Authors: Erick Paul Gutiérrez-Grijalva (Conacyt-CIAD Chairs), Alexis Emus-Medina (Faculty of Veterinary Medicine and Animal Husbandry, Autonomous University of Sinaloa), Laura Aracely Contreras-Angulo and José Basilio Heredia (Functional Foods and Nutraceuticals Laboratory, Center for Research in Food and Development).