Coffee with milk may have anti-inflammatory effect, says researchers

A simple cup of coffee with milk may have an anti-inflammatory effect in humans, a study conducted in laboratory suggests.

Researchers from the University of Copenhagen in Denmark found that a combination of proteins and antioxidants doubles the anti-inflammatory properties in immune cells.

Whenever bacteria, viruses and other foreign substances enter the body, our immune systems react by deploying white blood cells and chemical substances to protect us.

This reaction, commonly known as inflammation, also occurs whenever we overload tendons and muscles and is characteristic of diseases like rheumatoid arthritis.

Antioxidants known as polyphenols are found in humans, plants, fruits and vegetables. They are also known to be healthy for humans, as they help reduce oxidative stress in the body that gives rise to inflammation.

The study, published in the Journal of Agricultural and Food Chemistry, analysed how polyphenols behave when combined with amino acids, the building blocks of proteins.

"In the study, we show that as a polyphenol reacts with an amino acid, its inhibitory effect on inflammation in immune cells is enhanced. As such, it is clearly imaginable that this cocktail could also have a beneficial effect on inflammation in humans," said Professor Marianne Nissen from the University of Copenhagen.

"We will now investigate further, initially in animals. After that, we hope to receive research funding which will allow us to study the effect in humans," said Nissen, who led the study.

The researchers found that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that they studied.

To investigate the anti-inflammatory effect of combining polyphenols with proteins, the researchers applied artificial inflammation to immune cells.

Some of the cells received various doses of polyphenols that had reacted with an amino acid, while others only received polyphenols in the same doses. A control group received nothing.

The researchers found that immune cells treated with the combination of polyphenols and amino acids were twice as effective at fighting inflammation as the cells to which only polyphenols were added.

"It is interesting to have now observed the anti-inflammatory effect in cell experiments. And obviously, this has only made us more interested in understanding these health effects in greater detail. So, the next step will be to study the effects in animals," said Associate Professor Andrew Williams from the University of Copenhagen, who is also senior author of the study.

Previous studies by the researchers demonstrated that polyphenols bind to proteins in meat products, milk and beer.

In another new study, published in journal Food Chemistry, the researchers 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 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 have studied so far," said Nissen.

The researchers said it is possible that the reaction and potentially beneficial anti-inflammatory effect also occur when other foods consisting of proteins and fruits or vegetables are combined.