The water we drink from our taps may be an unsuspected cause of type II diabetes, the 'lifestyle' disease that can lead to heart problems and even death.
Although doctors have thought the disease is brought on by poor diet and lack of exercise, scientists believe that low levels of inorganic arsenic that are found in all our public drinking water may well be another cause.
Researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore have discovered that diabetics have a 26 per cent higher level of arsenic in their urine than healthy people. Overall, people with higher levels of arsenic have an almost four times greater risk of developing type II diabetes, they conclude.
The 788 people who took part in the study all live in areas of low and moderate levels of arsenic in their water supply, which suggests that the association could be even stronger in regions where arsenic levels are higher. In the USA, around 13 million people live in areas where inorganic arsenic levels in the public water supply are above levels regarded by the US Environmental Protection Agency as safe.
Inorganic arsenic, which enters the water supply from natural mineral deposits, can increase levels of glucose and insulin, and interfere with the uptake of glucose. Earlier studies - in Taiwan, Bangladesh and Mexico - had already established a link between arsenic in water and diabetes.
The Johns Hopkins researchers are also concerned that arsenic may cause cancer, heart disease and reproductive problems.
(Source: Journal of the American Medical Association, 2008; 300: 814-22).