Why It's a Good Idea to Use Milk in Coffee

Written by Henrik Rothen

Dec.14 - 2023 7:56 AM CET

Photo: Shutterstock.com
Photo: Shutterstock.com
Why It's a Good Idea to Use Milk in Coffee.

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Recent research from the University of Copenhagen suggests that something as simple as coffee with milk might have an anti-inflammatory effect on humans. This effect is due to a combination of proteins and special antioxidants that double the anti-inflammatory properties in immune cells.

When foreign substances like bacteria and viruses enter the body, the immune system responds by releasing white blood cells and chemical substances to protect the body. This reaction, known as inflammation, also occurs when tendons and muscles are overstrained and is present in diseases like rheumatoid arthritis.

In the human body, as well as in plants, fruits, and vegetables, there is a group of antioxidants called polyphenols. In the food industry, they are used to slow down oxidation and deterioration of food quality, preventing rancid and unwanted tastes. Polyphenols are also known to be healthy for humans as they similarly help to reduce oxidative stress in the body, which often causes inflammation.

However, much is still unknown about polyphenols. Few studies have examined what happens when polyphenols react with other molecules, such as proteins in food, before consumption.

In a new study, researchers from the Department of Food Science, in collaboration with researchers from the Department of Veterinary and Animal Sciences at the University of Copenhagen, investigated how polyphenols behave when combined with amino acids, the building blocks of proteins. "In the study, we show that when a polyphenol has reacted with an amino acid, the polyphenol acts extra inhibitory on inflammation in immune cells. Therefore, it is obvious to imagine that this cocktail could also have a beneficial effect on inflammation in humans. We now need to investigate this further, initially in animals, and then we hope to get research funds to examine it in humans as well," says Professor Marianne Nissen Lund from the Department of Food Science, who led the study.

To examine the anti-inflammatory effect of combining polyphenols with proteins, the researchers applied artificial inflammation to immune cells. Some cells received different doses of polyphenols that had reacted with an amino acid, while others only received polyphenols in the same doses. There was also a control group that did not receive anything. The researchers observed that the immune cells with the combination of polyphenols and amino acids were twice as effective at combating inflammation as those cells that only received polyphenols.

"It's interesting that we have now observed the anti-inflammatory effect in cell experiments, and it has certainly made us more interested in understanding the more detailed health effects, so the next step will be to investigate the effects in animals," says Associate Professor Andrew Williams from the Department of Veterinary and Animal Sciences at the Faculty of Health Sciences, who is also a senior author of the study.

The researchers have previously shown that polyphenols bind to proteins in meat products, milk, and beer. In another new study, they tested whether the molecules also bind to each other in a coffee drink with milk. Coffee beans are filled with polyphenols, while milk is rich in proteins. "Our result shows that the reaction between polyphenols and proteins also occurs in some coffee drinks with milk that we have examined. In fact, the reaction happens so quickly that it is difficult to avoid in all the foods we have examined so far," says Marianne Nissen Lund.

Therefore, it is also conceivable that the reaction and the possible beneficial anti-inflammatory effect also occur when we mix other foods consisting of proteins and fruits and vegetables in the kitchen, the researcher assesses. "I would think that a similar reaction between polyphenols and amino acids occurs in, for example, a meat dish with vegetables or a smoothie, if you make sure to include some protein, such as milk or yogurt," says Marianne Nissen Lund.

In the industry and the research world, the great benefits of polyphenols have been recognized. Therefore, work is being done on how to add polyphenols to foods in the right amounts to achieve the best quality. In this context, the new research results are promising: "Because we humans cannot absorb very much polyphenol at a time, there is currently a lot of research into encapsulating polyphenols in protein structures to improve their absorption in the body. And it seems that this strategy has the additional advantage of enhancing the anti-inflammatory effects of polyphenols," says Marianne Nissen Lund.

The research is funded by the Danish Free Research Fund and conducted in collaboration with the Technical University of Dresden in Germany.

Facts about Polyphenols:

  • Polyphenols are a group of naturally occurring antioxidants that are important for the human organism.

  • They prevent and delay the oxidation of other healthy chemical substances or organs in our body, thus preventing damage or destruction.

  • They are found in various vegetables and fruits, tea, coffee, red wine, and beer.

  • Due to their antioxidant properties, polyphenols are used to slow down the oxidation of fats and deterioration of food quality in the food industry, preventing rancid and unwanted tastes.