Can drinking tea help you to live longer?

Drinking two or more cups of tea per day is linked with a lower risk of death, compared with not drinking tea, according to a recent study published in the Annals of Internal Medicine.

Tea is known to contain beneficial compounds, such as antioxidants, that boost your overall health. Previous studies in China and Japan have suggested that drinking green tea regularly is linked with better health and a lower risk of dying. But past studies focusing on populations that mostly drink black tea haven’t given clear results.

The research team in this study wanted to look at the relationship between drinking tea and the risk of dying in a population where mostly black tea is drunk, so they used data from the UK Biobank, a biomedical database of people across the UK.

Using data from the UK Biobank, the study included responses from just under half a million men and women, aged 40 to 69. They reported the average number of cups of tea they drank in a day, whether it was black or green tea, and whether they added milk and sugar. Genetic tests were also used to predict the participants’ ability to process (metabolise) caffeine.

Of the regular tea drinkers included in study, about 90 per cent had black tea. The people questioned in the study were followed up for an average of 11 years. Compared with non-tea drinkers, people who reported drinking two or more cups of tea a day had a 9 to 13 per cent lower risk of dying from all causes.

When the researchers looked at specific causes of death, drinking tea was linked with a lower risk of dying from a stroke, coronary heart disease, and cardiovascular disease in general.

The study suggested that the risk of dying didn’t get lower with each additional cup of tea a day. The risk of dying was roughly similar for those drinking 2 to up to 10, or more, cups a day.

The researchers also found that the link between drinking tea and a lower risk of dying remained, even when people added milk or sugar to their tea, or when they were predicted to have a slower genetic ability to process caffeine.

The BHF verdict

This research suggests a link between drinking tea and a lower risk of dying, in particular from stroke or heart disease. These findings are in-line with those of previous research linking green tea with better health outcomes.

It is important to remember that this research shows a link, and does not prove cause and effect. Based on this research, we cannot say for certain that drinking tea will directly reduce your risk of dying. More research is needed.

Although this research suggests that drinking tea is linked with a lower risk of death, even when sugar is added, it is still important to think about limiting how much sugar you have in general.

Having too much sugar can lead to putting on excess weight, which is linked with an increased risk of coronary heart disease, strokes and developing type 2 diabetes. Before assuming that adding sugar to your tea is fine for your health, take stock of your sugar intake across your entire diet and make sure it is in-line with recommendations from the NHS.

• Get tips on cutting back on sugar

How good was the research?

One of the major strengths of this study was the large number of people included, which means the findings are more reliable.

This study also adjusted for a wide range of factors which could have influenced the results, including age, gender, underlying health conditions, whether people smoked, how much alcohol and coffee they drunk, and their diet.

However, some factors, such as the portion size and tea strength, were not included in the analysis and could have influenced the research findings.

A weakness of this study is that it relied on people self-reporting how much alcohol, tea and coffee they drunk and what was in their regular diet, which could make it less accurate. Also, most people only reported how much tea they had at the beginning of the study, so it’s possible they may have changed the amount of tea they had during the 11 years on average they were followed up.

How good was the media coverage?

This study was widely covered in the media, including in The Guardian, The Independent and The Daily Mail.

The Guardian article accurately reports the study and includes useful quotes from a professor of public health. This article also clearly states that the study only shows a link and that the researchers could not prove that the reduced risk of death is due to drinking tea.

The Independent article is mostly accurate and highlights that it should not be assumed that drinking tea will definitely improve your health and that this research does not provide enough evidence to suggest that people change their drinking habits.

However, The Independent article states that the beneficial effects are due to drinking ‘English Breakfast or Earl Grey’ tea. This is misleading as the study discusses only black tea in general and does not suggest the link with a lowered risk of dying is limited to any specific types of black tea.

Although the Daily Mail article is mostly accurate, the headline (“Why drinking tea could help you live longer”) might leave people thinking the research proves that tea is directly responsible for extending lives, when the study does not look at cause and effect, only the link between drinking tea and a lower death rate.

• Read more about research into tea and heart disease.

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