Tea is an ancient beverage with a rich history. There are all kinds of reasons someone may want to drink tea. Some people may drink tea for relaxation and pleasure, but others may have tea for religious or traditional reasons. Still others drink tea for its health benefits.
Why do people drink tea for their health? Drinking tea can reduce the risk of developing a range of disease, including type 2 diabetes, cognitive decline and specific cancers. However, drinking coffee or tea may result in adverse pregnancy outcomes. The World Health Organization (WHO) says “for pregnant women with high daily caffeine intake (more than 300 mg per day), lowering daily caffeine intake during pregnancy is recommended to reduce the risk of pregnancy loss and low birth weight neonates.”
Why do people like to drink tea? It turns out there are a lot of reasons to enjoy tea, as well as some reasons to think twice about consuming it. When you consider how extensive the health implications of tea consumption are, it’s clear that knowing what environmental and genetic factors cause people to drink more or less of it is important. Could genetic factors for AHR gene caffeine affect tea consumption?
Previous research has revealed that the perception of taste and our resulting preferences are inherited. We’ve always known that answering the question, “Why do people drink tea?” may require genetic research. A recent study has revealed even more about the connection between tea drinking and genetics. This randomized Mendelian analysis found that the perception of bitter taste had a casual relationship with the consumption of coffee, tea, alcohol, and other bitter beverages.
In this study, researchers performed a genome-wide association study (GWAS) of self-reported bitter and sweet beverage consumption among ~370,000 participants. They were enrolled in 2 stages: stage 1 included participants of European ancestry from the UK Biobank, and stage 2 included participants from 3 US-based cohorts. For the purposes of this study, coffee, tea, grapefruit juice, red wine, liquor and beer were considered bitter beverages, while sweet beverages included non-grapefruit juices and artificially and sugar sweetened beverages (SSBs). In comparing the results of stages 1 and 2, seven independent SNPs mapped to five loci were replicated for bitter non-alcoholic beverage consumption. Three SNPs, rs2813703 in/near ESRRG gene, rs1481012 in/near ABCG2 gene, and rs4410790 in/near AHR gene, demonstrated strong associations with tea consumption in participants from the UK Biobank, although they were not replicated in US cohorts. The ABCG2 gene contains loci that have previously been associated with plasma caffeine metabolites, meaning it plays a role in the body’s ability to process caffeine.
Other SNPs near caffeine-related loci, such as AHR and CYP1A1/2, were associated with tea consumption in the UK Biobank, but they were also not replicated in the US cohorts. This discrepancy between study populations could be due to the fact that tea is a major source of caffeine in the UK, but not in US populations. Replication may have been impeded by the strong cultural differences of tea drinking behaviors between the two countries. You can read more about the study here: https://www.ncbi.nlm.nih.gov/pubmed/31046077
Stil wondering “Why do people like to drink tea so much?” Maybe you’re an avid fan of tea and can’t imagine why someone wouldn’t like it. Are you interested in learning more about your genetic tendency for tea consumption? You can login to your Genomelink dashboard to see this new genetic trait.