Mountain Dwellers in Argentina Have Adapted to High Arsenic Levels

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A new study appears to offer the first evidence of people adapting to tolerate the toxic chemical arsenic.

Arsenic — the killer used by many murder mystery villains — is most toxic to young children and people in their prime reproductive years. The ability to metabolize arsenic quickly may been the difference between life and death in ancient times, said study leader Karin Broberg, a professor at the Karolinska Institute and Uppsala University in Sweden, and colleagues.

The research included 124 women living high up in the Andes mountains of Argentina in an area where arsenic in the volcanic bedrock is released into the groundwater. For thousands of years, people in the region have been exposed to high levels of arsenic.

Urine tests showed the women were able to metabolize arsenic. Genetic tests showed they had higher-than-normal rates of variants of a gene called AS3MT that help protect them against arsenic, the Swedish researchers said.

Based on the age of an excavated mummy that was found to have high arsenic levels in its hair, the researchers concluded that the higher rate of variants of this gene occurred between 7,000 and 10,000 years ago.

It likely occurred as a result of the severe health effects of arsenic, according to the study published online recently in the journal Molecular Biology and Evolution.

More information

The U.S. Agency for Toxic Substances and Disease Registry has more about arsenic.

Source: HealthDay

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