Ramadan fasting alters arsenic metabolism

People who fast during religious festivals excrete more of a toxic form of arsenic from the body than those who eat at regular intervals.

The news is reported in the latest edition of the Royal Society of Chemistry's Journal of Environmental Monitoring.

Millions of people in some of the poorest regions of the world are exposed to high levels of arsenic through drinking contaminated water.

Many of the people affected also fast for one month of the year during Ramadan, when they don't drink or eat during daylight hours. 

But the effect of fasting on arsenic metabolism has remained unknown until now.

Long term exposure to arsenic in drinking water is known to cause cancer of the skin, lungs, bladder and kidneys as well as causing changes to the skin such as pigmentation and thickening.

Dr Parvez Haris and a team De Montfort University in Leicester, in conjunction with researchers based in Manchester, studied the effect of fasting on how arsenic is excreted in urine.

The study involved a group of UK volunteers who were fasting for Ramadan.

He said: "The subjects were not exposed to contaminated water, but arsenic was present at a natural background level. The volunteers provided urine samples first thing in the morning, at the beginning of their fast, and again at sunset when fasting ended."

After analysis of the samples using mass spectrometry, the research teams found that one particularly toxic arsenic species, methylarsonate, was found more frequently in the evening samples than the morning ones.

Dr Haris said: "The results show that fasting changes how the body metabolises arsenic, favouring the removal of the most toxic arsenic species present."

The team now want to extend their research to include residents of Bangladesh and India, who are regularly exposed to high levels of arsenic.

Dr Helen Rowland, an expert in arsenic based at the Royal Society of Chemistry, said: "Arsenic poisoning is a huge problem, yet it is rarely reported in the news.

"It is a big problem in India, West Bengal and Bangladesh, and recent discoveries of arsenic in ground water supplies in Cambodia, Vietnam and other regions of South East Asia mean that poisoning could affect millions more than first thought.

"The arsenic is naturally occurring but can have a devastating affect on these populations and the economy in those regions, since these people have no choice but to drink this water."

with thanks to Nicola Burton for the original article

References

Effect of fasting on the pattern of urinary arsenic excretion  E I Brima, R O Jenkins, P R Lythgoe, A G Gault, D A Polya and P I Haris, J. Environ. Monit., 2007 DOI: 10.1039/b613340a