Hello and welcome to More or Less on the BBC World Service with me Tim Halford.

With a programme that knows when the world doesn't make much sense,

it's numbers that might just show you the story that's been hidden under the surface all along.

Now here at More or Less we never turn down the offer of a good cup of tea.

Unless it's using one of the tea bags we get in the BBC office kitchens,

trust me, you don't want to try them.

But on the whole we're a big fan of the beverage in all its many forms,

whether that's Genmei Char, Asam or Ulong.

And it turns out the power of tea might be greater than just clearing your head or giving you a gentle lift.

A new economics paper argues that the widespread adoption of tea drinking in 18th century England

with the accompanying practice of boiling water had the unintended side effect of saving lives,

leading to a marked decline in the country's death rate.

I spoke to the paper's author, Francisco Antman, an associate professor in economics at the University of

Colorado Boulder in the United States. I started by asking what got her onto the subject of drinking tea.

Well it was something of an epiphany I will say, so I was really starting out as an assistant

professor here in Boulder. I had also recently had a child and I was really locked in this personal

internal struggle over whether I needed to boil the water to give my child his first drink of water.

And I remember talking to the pediatrician here in Boulder, Colorado, and the pediatrician saying,

why is this even a question for you? You can give the baby tap water, but because although I am an

American, I still have a lot of family that's in Mexico and I spent a lot of time there growing up,

you certainly wouldn't drink water from the tap and you would never give a baby water that had

not been boiled first. And this is a huge global issue. The World Health Organization estimates that

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