Enjoying a cuppa already comes with numerous health benefits. But thanks to new research, the world’s most popular hot beverage could have new appeal to those who struggle to sleep.

Prof. Ju-Sheng Zheng, who heads the Precision Nutrition and Computational Medicine Lab and served as a postdoctoral fellow at the University of Cambridge, recently published a study detailing how regular consumption of tea could reduce the effects of chronic insomnia on the body, including gut health. We asked him to explain the science behind these findings.

What is chronic insomnia and how is it related to our gut?

Chronic insomnia is a sleep disorder. People who have this condition will find it difficult to fall asleep at least three times per week over at least three months.

What we found is that the gut microbiome and gut ecosystem could be significantly disrupted by chronic insomnia.

Our gut microbiome is very important to the human body. Gut microbiota also converts the bile acid synthesized in the liver into functional metabolites. We call this the gut microbiota-bile acid axis, and it is essential for human health.

After following 2,000 people over six years, we found that chronic insomnia is associated with lower levels of key microbiota, which are vital for your health. We also found that chronic insomnia is related to the disruption of bile acid metabolites.

Overall, our data among a Chinese population shows that chronic insomnia is linked to worse gut microbiota levels and worse gut health status.

Our data also directly show that this microbiota disruption can lead to a higher risk of cardiovascular disease, diabetes and metabolic syndrome.

How can drinking tea help with chronic insomnia and the gut ecosystem?

What we found among these over 2,000 people is that chronic insomnia over time will disrupt our gut ecosystem, decreasing the number of good bacteria.

We wanted to assess how diet and lifestyle could moderate this disruption of the gut microbiota ecosystem.

Among all the data factors, we discovered tea plays the most significant role. Those key bacteria, which were significantly reduced in number by chronic insomnia, could be increased by drinking tea.

We hypothesize that tea drinking could attenuate the harmful effects of chronic insomnia on the gut ecosystem.

Did the variety of tea make a difference?

We didn't find any difference, as the subjects in our population drank diverse varieties of tea such as oolong, green or black. One variety of tea was not better than another.

What we want to argue is that, overall, habitual tea drinking is beneficial for our gut microbiome ecosystem, and that it will attenuate the harmful effects of chronic insomnia on our body.

If someone has chronic insomnia and wants to drink tea to improve their health, what's your recommendation?

I would not advise drinking tea later in the day, as this can greatly influence your ability to sleep.

Drinking tea in the morning or early in the afternoon would be a good option for people who want to improve their gut health and offset the effects of insomnia on the body.

Read more about the study here: https://www.nature.com/articles/s41467-022-30712-x