Forget what mom said, that daily shower can be damaging your brain

Jul 21, 2005, 4:11 GMT

Washington - Traces of magnesium found in household water could be sufficient to cause permanent brain damages to those who take a regular shower, according to a report published in the U.S. journal Medical Hypotheses.

John Spangler of the Wake Forest University School of Medicine in North Carolina and is team suggested that breathing in vapour containing manganese salts could be dangerous over the longer term.

"Inhaling manganese, rather than eating or drinking it, is far more efficient at delivering manganese to the brain. The nerve cells involved in smell are a direct pathway for toxins to enter the brain," Spangler wrote.

The team used animal studies aimed at showing how much a person who showered for 10 minutes a day would absorb.

The effects are dependent on the levels of manganese in household water. In the United States, a limit of 0.5 milligrams a litre of water is imposed by the Environmental Protection Agency, while in the European Union, an upper level of just a 10th of that was set only in 1998.

Spangler suggested that even levels below the U.S. upper llimit could lead to brain damage.

Ten years of showering in water containing concentrations of manganese around the U.S. limit would expose young people to levels three times higher than that found to leave deposits in rats' brains.

The longer the exposure, the worse the risk.

Manganese poisoning leads to tremors in sufferers - much like Parkinson's disease.

Apart from natural sources in ground water, manganese is sometimes added to petrol. This also finds its way ultimately into drinking water.