A cup of coffee with milk may have anti-inflammatory properties, according to a study published in the Journal of Agricultural and Food Chemistry. A team of researchers from the University of Copenhagen found that a combination of proteins and antioxidants increases the anti-inflammatory properties in immune cells. Next, the researchers want to assess how this affects human health.
A group of antioxidants known as polyphenols can be found in a variety of fruits and vegetables. These antioxidants are also commonly used in the food industry to slow down oxidation in different food items and avoid rancid flavours. Consuming foods rich in polyphenols is healthy for humans, as they help reduce oxidative stress and control inflammation.
But there’s still much we don’t know about polyphenols. Not many studies have looked at how these antioxidants react with other chemicals, such as proteins, mixed into foods that we then eat. To address this gap, in a new study, researchers at the Department of Food Science, in collaboration with researchers from the Department of Veterinary and Animal Sciences, at the University of Copenhagen, assessed how polyphenols behave when mixed with different amino acids.
The results look very promising for reducing inflammation. “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. 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 Professor Marianne Nissen Lund from the Department of Food Science, who headed the study.
To investigate this effect, the team combined polyphenols with proteins and created artificial inflammation in immune cells. These cells were twice as effective at fighting inflammation compared to cells that only received polyphenols. “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 of the Department of Veterinary and Animal Sciences at the Faculty of Health and Medical Sciences, who is also a senior author of the study.
Previous studies by the same team showed that polyphenols could bind to proteins present in meat, milk, and beer. One of the examples studied was a cup of coffee 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,” said Prof Lund.
For the team, it’s not hard to imagine that this drink can have anti-inflammatory properties for humans, as well as any other combination of polyphenols and proteins, such as meat and vegetables. “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,” said Prof Lund.
The food industry knows how beneficial polyphenols can be, and they’re working on adding the right quantities of polyphenols in foods to achieve the best quality. This new research can add a way to promote the absorption of polyphenols. “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,” concluded Prof Lund.
Liu J, Poojary M, Zhu L, Williams A, and Lund M (2023) Phenolic Acid–Amino Acid Adducts Exert Distinct Immunomodulatory Effects in Macrophages Compared to Parent Phenolic Acids. Journal of Agricultural and Food Chemistry 2023 71 (5), 2344-2355, DOI: 10.1021/acs.jafc.2c06658