USA - Should you skip your next sip of water? US entrepreneur and multimillionaire Bryan Johnson (47) is obsessed with his health - and is now warning against one of the most common things in the world.

In an interview with the British Daily Mail, the 47-year-old claimed that drinking water laced with fluoride could lower IQ.

To back this up, he referred to several studies that he and his team had checked in order to test a thesis by Robert Kennedy Jr (71).

The new US Secretary of Health and Human Services had already pointed out the potential danger during the US election campaign and subsequently announced that he would remove the salts from tap water as soon as he took office. They are said to be responsible for arthritis, bone cancer and reduced intelligence, among other things.

"Removing fluoride seems to be a decision based on scientific evidence. So removing it from the water supply is a good approach," explained Johnson, who recently gained greater notoriety in the Netflix documentary "Don't Die: The Man Who Wants to Be Immortal".

So should we also be worried the next time we go to the tap in this country? According to a report by Deutsche Welle, fluorides - salts of hydrofluoric acid - are naturally present in many foods, the human body and drinking water.

They also work in toothpaste and prevent tooth decay. This is why fluorides have been added to drinking water in many countries over the years, including the USA. Not so in Germany, however.

According to the Federal Institute for Consumer Health Protection and Veterinary Medicine, the daily intake among people in Germany is very low.

There are no additionally fluoridated foods here, so there are no health effects to be feared. Overdosing with toothpaste is also virtually impossible.

However,a meta-studypublished in 2023 shows that the amount added in the USA and classified as harmless by the local health authority can indeed have negative effects on brain development - especially in children.