In order to record coffee consumption in nutrition and health studies, researchers usually rely on self-reporting by participants. However, this is not always reliable. It would therefore be desirable to conduct additional studies to objectively verify individual consumption using biomarkers. A research team led by the Leibniz Institute for Food Systems Biology at the Technical University of Munich has now validated the suitability of a specific roasted coffee compound and proposes it as a new, practical food biomarker.

Millions of people around the world drink coffee every day. The beverage contains a large number of bioactive substances, and its health effects on the human metabolism are therefore frequently subjects of scientific studies. In many of these studies, however, the data on coffee consumption is largely based on self-reporting by the participants and is therefore not always accurate. This can affect the scientific validity of nutritional studies.

Biomarkers could provide a remedy

Reliable biomarkers could remedy this problem by using biological samples to objectively distinguish between coffee drinkers and non-coffee drinkers. “So far, however, only a few substances are known that could be used as coffee markers,” says principal investigator Roman Lang from the Leibniz Institute. “However, these are not yet sufficiently validated or available in sufficient quantities to serve as reference substances for comparative measurements in nutritional studies,” he continues.

The research team, which also includes the nutritional physician Thomas Skurk and first author Beate Brandl from the ZIEL – Institute for Food & Health at the Technical University of Munich, has therefore comprehensively validated the roast coffee compound N-methylpyridinium as one such biomarker candidate for its suitability. Researchers at the Technical University of Munich first proposed the substance as a biomarker candidate in 2011 as part of a pilot study.

Data from over 460 people analyzed

As part of the scientific validation, the team analyzed existing literature data. It also analyzed urine, blood and plasma samples from more than 460 people from Freising and Nuremberg who had participated in a nutrition study conducted by the BMBF-funded enable cluster.

As the study shows, N-methylpyridinium is a compound that is specific to roasted Arabica and Robusta coffee. The substance is chemically very stable and its absorption into the organism is concentration-dependent. The substance can also be easily and reproducibly detected in various body fluids after coffee consumption, before leaving the body unchanged in the urine within a few hours to days.

Roman Lang, who heads the Biosystems Chemistry & Human Metabolism research group at the Leibniz Institute, explains: “As we have shown, N-methylpyridinium fulfills all the criteria that science demands of a biomarker to control food intake. Even if we cannot draw direct conclusions about the amount of coffee consumed due to various factors, the roasting substance is still suitable as a marker. This is because it allows us to distinguish objectively and practically between people who have drunk coffee and those who have not. We therefore propose it as a reliable qualitative biomarker for coffee consumption.”

Publication: Brandl, B., Czech, C., Wudy, S.I., Beusch, A., Hauner, H., Skurk, T., and Lang, R. (2024). Validation of N-Methylpyridinium as a Feasible Biomarker for Roasted Coffee Intake. Beverages 10, 12. 10.3390/beverages10010012. www.mdpi.com/2306-5710/10/1/12

More Information:

About N-methylpyridinium:

N-methylpyridinium was already proposed as a biomarker candidate for coffee consumption in 2011: Lang et al., 2011 onlinelibrary.wiley.com/doi/10.1002/mnfr.201000656

N-methylpyridinium is formed from the natural alkaloid trigonelline, which is abundant in green coffee, when exposed to high heat at over 220 °C. Depending on the degree of roasting, roasted Arabica and Robusta coffee beans contain concentrations of around 0.5 to 2 mg/g of the substance – regardless of special processing methods such as steaming or decaffeinating. N-methylpyridinium is contained in brewed coffee (20-40 mg/l) and can be easily detected in blood, plasma and urine samples.

Coffee consumption in Europe and the USA:

In the USA alone, 74 percent of the population over the age of 20 describe themselves as coffee drinkers. In European countries, the calculated per capita consumption of roasted coffee in 2022 ranged from around 4 kilograms in Italy to 10 kilograms in Luxembourg.

Validation criteria:

The validation was based on criteria already proposed in 2018 for food biomarkers: plausibility, dose-response, time-response, robustness, reliability, stability, analytical performance and reproducibility. Dragsted, L.O. et al. 2018. www.ncbi.nlm.nih.gov/pmc/articles/PMC5975465/pdf/12263_2018_Article_603.pdf

Read also: New biomarkers for coffee consumption

www.leibniz-lsb.de/presse-oeffentlichkeit/pressemitteilungen/pm-20221207-pressemitteilung-biomarker-kaffeekonsum/

Information on the enable cluster: www.enable-cluster.de

Contacts:

Scientific contact:

Dr. Roman Lang
Head of Research Group Biosystems Chemistry & Human Metabolism
Leibniz Institute for Food Systems Biology
at the Technical University of Munich (Leibniz-LSB@TUM)
Lise-Meitner-Str. 34
85354 Freising/Germany
Phone: +49 8161 71-2978
E-mail: r.lang.leibniz-lsb(at)tum.de
Profile: www.leibniz-lsb.de/en/institute/staff/profile-dr-roman-lang/

Press contact at Leibniz-LSB@TUM:

Dr. Gisela Olias
Knowledge Transfer, Press and Public Relations
Phone: +49 8161 71-2980
E-mail: g.olias.leibniz-lsb(at)tum.de
www.leibniz-lsb.de

Information about the Institute:

The Leibniz Institute for Food Systems Biology at the Technical University of Munich (Leibniz-LSB@TUM) comprises a new, unique research profile at the interface of Food Chemistry & Biology, Chemosensors & Technology, and Bioinformatics & Machine Learning. As this profile has grown far beyond the previous core discipline of classical food chemistry, the institute spearheads the development of a food systems biology. Its aim is to develop new approaches for the sustainable production of sufficient quantities of food whose biologically active effector molecule profiles are geared to health and nutritional needs, but also to the sensory preferences of consumers. To do so, the institute explores the complex networks of sensorically relevant effector molecules along the entire food production chain with a focus on making their effects systemically understandable and predictable in the long term.

The Leibniz-LSB@TUM is a member of the Leibniz Association, which connects 97 independent research institutions. Their orientation ranges from the natural sciences, engineering and environmental sciences through economics, spatial and social sciences to the humanities. Leibniz Institutes devote themselves to social, economic and ecological issues. They conduct knowledge-oriented and application-oriented research, also in the overlapping Leibniz research networks, are or maintain scientific infrastructures and offer research-based services. The Leibniz Association focuses on knowledge transfer, especially with the Leibniz Research Museums. It advises and informs politics, science, business and the public. Leibniz institutions maintain close cooperation with universities – among others, in the form of the Leibniz Science Campuses, industry and other partners in Germany and abroad. They are subject to a transparent and independent review process. Due to their national significance, the federal government and the federal states jointly fund the institutes of the Leibniz Association. The Leibniz Institutes employ around 21,000 people, including almost 12,000 scientists. The entire budget of all the institutes is more than two billion euros.

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