How Britain's taste for tea may have been a life saver

In the 18th Century, tea rapidly became a cherished resource of the British Empire. However, it may have had an unexpected impact on the British population - it may have reduced mortality rates. This is the argument put forth by economist Francisca Antman of the University of Colorado, Boulder, in a recent paper in the Review of Statistics and Economics.

Antman posits that the widespread practice of boiling water to make tea, in a time when people were unaware that water-borne pathogens could cause illness, may have inadvertently saved many lives. This is because boiling water kills bacteria that cause diseases such as dysentery, which was a prevalent issue in the era, particularly in densely populated towns with poor sanitation.

Between 1761 and 1834, the annual death rate in England declined significantly, from 28 to 25 per 1,000 people. However, this decrease in mortality did not coincide with an increase in wages or living standards. In fact, the industrial revolution led to an increase in urbanization, resulting in overcrowded towns with subpar sanitation. Antman suggests that the widespread consumption of tea, and the consequent boiling of water, may have been a contributing factor to the decrease in mortality.

To test her hypothesis, Antman analyzed geographical information from over 400 parishes across England. She made the assumption that areas with more water sources likely had cleaner water, as inhabitants could switch sources if one was contaminated. Furthermore, she inferred that water from sources higher up in a river was likely safer than water from downstream sources.

The key date in testing this hypothesis is 1785, when tea became affordable for the majority of Britons due to a significant reduction in tea tax. Antman examined whether areas with worse water quality saw a larger decline in mortality than those with good water following this change. She found that parishes with bad water saw death rates drop 18% more than those with good water, suggesting that the widespread consumption of tea may indeed have had a significant impact on public health.

Antman's study highlights the potential for everyday behaviors to have a significant impact on health outcomes. In this case, the simple act of boiling water for tea may have inadvertently protected many people from water-borne diseases, contributing to a decrease in mortality rates.