It seems that we cannot drink too much tea in light of the results of a study carried out by researchers at the University of Uppsala (Sweden) and collected in the journal Human Molecular Genetics. The reason? Experts have found that this popular drink affects gene expression. Specifically, it leads to epigenetic changes in women that are associated with cancer and estrogen hormone metabolism.
Epigenetics refers to the study of changes in gene expression that can be passed on to future generations. It examines how external factors, such as the environment and lifestyle, affect the genes that are turned on and off, and how this influences one’s health and the health of children.
In this study, the researchers set out to investigate whether the consumption of tea and coffee – two of the most popular beverages – could lead to epigenetic changes in both men and women.
To do this, they analyzed data from 3,096 adults from four European cohorts. They examined the participants’ tea and coffee consumption and evaluated their blood samples for DNA methylation , an indicator of changes in gene expression.
The results revealed no changes in DNA methylation in either sex as a result of coffee consumption. However, tea consumption was associated with alterations in DNA methylation across 28 genomic regions, but only in women . That is, drinking tea caused changes in gene expression only in women. In particular, the researchers found that drinking tea appeared to alter the expression of DNAJC16 and TTC17, genes associated with estrogen metabolism and cancer.
“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 “, explains Weronica Ek, leader of the work.
More research is needed to determine whether this effect in women is positive or negative.
Reference: Tea and coffee consumption in relation to DNA methylation in four European cohorts
Weronica E. Ek Elmar W. Tobi Muhammad Ahsan Erik Lampa Erica Ponzi Soterios A. Kyrtopoulos Panagiotis Georgiadis LH Lumey Bastiaan T. Heijmans Maria Botsivali. Human Molecular Genetics. May 2017. DOI: doi.org/10.1093/hmg/ddx194
