Devotees claim that raw or “live” water taken directly from its natural source has a whole host of health benefits, thanks to the presence of mineral compounds and probiotics.

But what about harmful bacteria, parasites , and viruses, and the risk of infection?

“We’ve spent generations of science and effort to try and protect people from drinking raw water. It seems extraordinary that people want to go back to medieval times when millions of people died from infections that were carried by it,” says Val Curtis, Professor of Hygiene and Director of the Environmental Health Group at the London School of Hygiene and Tropical Medicine.

According to global health expert Curtis, the purpose of water is not nutrition – it’s hydration. “We need H20,” she says. “If we need any other minerals or magic compounds, we get them from our food. Water is not for nutrition, and the dangers of raw water outstrip any benefits by far.”