Summary: According to researchers, tea consumption leads to epigenetic changes in women, involving genes associated with cancer and estrogen metabolism.

Source: Uppsala University.

Epigenetic changes are chemical modifications that turn our genes off or on. In a new study from Uppsala University, researchers show that tea consumption in women leads to epigenetic changes in genes that are known to interact with cancer and estrogen metabolism. The results are published in the journal Human Molecular Genetics.

It is well known that our environment and lifestyle factors, such as food choices, smoking and exposure to chemicals, can lead to epigenetic changes. In the current study, researchers from Uppsala University in collaboration with research groups around Europe, investigated if coffee and tea consumption may lead to epigenetic changes. Previous studies have suggested that both coffee and tea play an important role in modulating disease-risk in humans by suppressing tumour progression, decreasing inflammation and influencing estrogen metabolism, mechanisms that may be mediated by epigenetic changes.

The results show that there are epigenetic changes in women consuming tea, but not in men. Interestingly, many of these epigenetic changes were found in genes involved in cancer and estrogen metabolism. ”Previous studies have shown that tea consumption reduces estrogen levels which highlights a potential difference between the biological response to tea in men and women. Women also drink higher amounts of tea compared to men, which increases our power to find association in women”, says Weronica Ek, researcher at the Department of Immunology, Genetics and Pathology, who led the study. The study did not find any epigenetic changes in individuals drinking coffee.

Results from this study highlight the role of pharmacologically active components in tea being involved in cancer and estrogen metabolism, which can reflect that health effects related to tea consumption might be due to epigenetic changes. However, this study does not show if it is healthy or not to drink tea and further research is needed to understand how epigenetic changes found in this study affects our health. It has previously been demonstrated that tea catechins lead to epigenetic changes in vitro and in cultured cancer cells, arguing that some of the health effects of tea may be mediated by epigenetics.

Source: Linda Koffmar – Uppsala University 
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Tea and coffee consumption in relation to DNA methylation in four European cohorts” by Weronica E. Ek, Elmar W. Tobi, Muhammad Ahsan, Erik Lampa, Erica Ponzi, Soterios A. Kyrtopoulos, Panagiotis Georgiadis, L.H Lumey, Bastiaan T. Heijmans, Maria Botsivali, Ingvar A. Bergdahl, Torgny Karlsson, Mathias Rask-Andersen, Domenico Palli, Erik Ingelsson, Åsa K. Hedman, Lena M. Nilsson, Paolo Vineis, Lars Lind, James M. Flanagan, Åsa Johansson on behalf of the Epigenome-Wide Association study Consortium in Human Molecular Genetics. Published online May 23 2017 doi:10.1093/hmg/ddx194

Abstract

Tea and coffee consumption in relation to DNA methylation in four European cohorts

Lifestyle factors, such as food choices and exposure to chemicals, can alter DNA methylation and lead to changes in gene activity. Two such exposures with pharmacologically active components are coffee and tea consumption. Both coffee and tea has been suggested to play an important role in modulating disease-risk in humans by suppressing tumour progression, decreasing inflammation and influencing estrogen metabolism. These mechanisms may be mediated by changes in DNA methylation.

To investigate if DNA methylation in blood is associated with coffee and tea consumption we performed a genome-wide DNA methylation study for coffee and tea consumption in four European cohorts (N = 3,096). DNA methylation was measured from whole blood at 421,695 CpG sites distributed throughout the genome and analysed in men and women both separately and together in each cohort. Meta-analyses of the results and additional regional-level analyses were performed.

After adjusting for multiple testing, the meta-analysis revealed that two individual CpG-sites, mapping to DNAJC16 and TTC17, were differentially methylated in relation to tea consumption in women. No individual sites were associated in men or in the sex-combined analysis for tea or coffee. The regional analysis revealed that 28 regions were differentially methylated in relation to tea consumption in women. These regions contained genes known to interact with estradiol metabolism and cancer. No significant regions were found in the sex-combined and male-only analysis for either tea or coffee consumption.

“Tea and coffee consumption in relation to DNA methylation in four European cohorts” by Weronica E. Ek, Elmar W. Tobi, Muhammad Ahsan, Erik Lampa, Erica Ponzi, Soterios A. Kyrtopoulos, Panagiotis Georgiadis, L.H Lumey, Bastiaan T. Heijmans, Maria Botsivali, Ingvar A. Bergdahl, Torgny Karlsson, Mathias Rask-Andersen, Domenico Palli, Erik Ingelsson, Åsa K. Hedman, Lena M. Nilsson, Paolo Vineis, Lars Lind, James M. Flanagan, Åsa Johansson on behalf of the Epigenome-Wide Association study Consortium in Human Molecular Genetics. Published online May 23 2017 doi:10.1093/hmg/ddx194