Arsenic-tainted rice increases risk of cancer, study shows
Rice tainted with high levels of arsenic has been linked to genetic damage that heightens the risk of cancer.
Naturally occurring arsenic in water is a long-known health hazard, especially in Bangladesh, where millions of people depend on wells drilled in the 1970s.
Scientists have also fretted about rice grown in contaminated groundwater. But new research is the first to have found proof of a risk.
Researchers at the University of Manchester in England and the Indian Institute of Chemical Biology in Calcutta carried out a study with the help of 417 villagers in West Bengal.
They asked the volunteers to provide details about their lifestyle and the amount of rice they ate, and to provide samples of cooked rice and their urine.
The volunteers came from three areas but had a similar diet and socio-economic status. All had a low exposure to arsenic through their drinking water.
The researchers sifted through the urine samples to extract cells from the lining of the urinary tract, which were then analysed for genetic signatures called micronuclei. Micronuclei are tiny pieces of DNA that are left over from when a cell replicates and fails to copy its genetic code properly.
Previous research has found that the more frequently cells make a mistake in copying the code, the greater the risk that they will become cancerous. A higher count of micronuclei is thus a barometer of the risk.
What they found was that micronuclei frequency rose with increasing arsenic levels in rice. The trend was true both for men and women and for tobacco and non-tobacco users.
The study, published in Nature Group's Scientific Reports journal, did not have the scope to monitor the volunteers for health problems.
But it says the findings should sound the alarm for people who consume large daily helpings of rice grown in high-arsenic water areas.