In search of new biomarkers for nutrition and health studies, a research team from the Leibniz Institute for Food Systems Biology at the Technical University of Munich (LSB) has identified and structurally characterized three metabolites that could be considered as specific markers for individual coffee consumption. These are degradation products of a group of substances that are formed in large quantities during coffee roasting but are otherwise rarely found in other foods. This and the fact that the potential biomarkers can be detected in very small amounts of urine make them interesting for future human studies.
According to Statista, coffee is by far the most popular hot beverage in Germany. On average, around 168 liters are consumed per person per year. German culture has a long history of coffee drinking, and the country is known for its high-quality coffee roasts and blends. Many Germans enjoy drinking coffee at cafes, in restaurants, and at home, and it is often served with sweet treats such as pastries or cookies.
It is not only a stimulant, but also has positive health properties. For example, numerous observational studies indicate that moderate coffee consumption is associated with a reduced risk of type 2 diabetes or liver disease. Coffee contains antioxidants, which can help protect cells from damage. It also contains caffeine, which can help increase alertness and improve physical performance. Some studies have also found that drinking coffee may help lower the risk of developing certain diseases, such as Parkinson’s disease.
However, it’s important to note that some people may be sensitive to the effects of caffeine, and may need to limit their intake of coffee to avoid negative side effects such as jitteriness, anxiety, or difficulty sleeping.
Biomarkers instead of self-reporting
However, with regard to the amounts of coffee drunk, such observational studies rely on participants’ self-reports, which are difficult to verify. “Complementary studies would therefore be desirable in which coffee consumption could be objectively verified using biomarkers in order to determine the health value of coffee even more reliably,” says Roman Lang, who heads the Biosystems Chemistry & Human Metabolism research group at LSB.
Although earlier studies had already pointed to biomarker candidates, research on this had stalled for years. The substances previously detected were metabolic intermediates or breakdown products (metabolites) of various coffee compounds whose urine concentrations correlated strongly with the level of coffee consumption. At the time, however, the researchers had not succeeded in clearly identifying the molecular structure of the metabolites.
Use of high-performance analytical technologies
Therefore, as part of a pilot study, Roman Lang’s team examined the urine samples of six people after they had consumed 400 ml of coffee three hours earlier. With the help of high-performance analytical technologies and self-produced reference substances, the team succeeded in identifying three candidate biomarkers in the urine and, for the first time, in clearly determining their chemical structure. These are a glucuronic acid conjugate of atractyligenin, whose glycosides are present in relatively high concentrations in coffee beverages, and two glucuronic acid derivatives of an atractyligenin oxidation product.
“Our findings help advance biomarker research,” says Roman Lang. Dose-response studies, pharmacokinetics and human studies with much larger numbers of subjects must now follow to test the biomarker suitability of the identified compounds, he adds. Veronika Somoza, director of the Freising-based Leibniz Institute adds, “Food-specific biomarkers are important tools to explore the health effects of food. Therefore, part of our scientific work at LSB is also focused on finding biomarkers for food consumption.”
Function of glucuronic acid conjugates
Glucuronic acid is a type of sugar that is found in the human body. It plays a role in several important functions, including the synthesis of glycogen (a type of carbohydrate that is stored in the liver), and the formation of certain types of connective tissue. In human metabolism, glucuronic acid serves in particular the so-called “detoxification” of nonpolar substances. This process is known as glucuronidation, and it is an important part of the body’s natural detoxification system. The latter include, for example, ingested drugs or plant substances, but also endogenous steroid hormones. The body converts the substances to glucuronides in the liver by binding them to glucuronic acid. These glucuronic acid conjugates are much more water-soluble than the original substances and can thus be easily excreted in the urine via the kidneys.
If you are sensitive to the effects of caffeine or are experiencing negative side effects from drinking coffee, there are a few steps you can take to reduce or eliminate these effects. Here are some possible suggestions:
Drink coffee in moderation: Try to limit your intake of coffee to no more than 2-3 cups per day. This will help reduce the amount of caffeine you are consuming, which can help reduce or prevent negative side effects.
Choose decaf: Decaf coffee contains very little caffeine, so switching to decaf can help reduce your caffeine intake without sacrificing the taste or experience of drinking coffee.
Drink coffee earlier in the day: Caffeine can stay in your system for several hours, so if you are sensitive to its effects, try to avoid drinking coffee late in the day. This will help prevent caffeine from interfering with your sleep.
Drink coffee with food: Consuming caffeine on an empty stomach can cause it to be absorbed more quickly into your system, which can increase its effects. Drinking coffee with food can help slow down the absorption of caffeine, which can reduce or prevent negative side effects.
Try other beverages: If you are sensitive to caffeine or experiencing negative side effects from drinking coffee, you may want to try other beverages that do not contain caffeine. For example, herbal teas, fruit juices, or water can all be good alternatives to coffee.