Researchers at the Mailman School of Public Health have found that folic acid supplements can dramatically lower blood arsenic levels in people exposed to arsenic through contaminated drinking water. Naturally present in some aquifers used for drinking, arsenic is a significant public health problem in at least 70 countries, including several developing nations, and also parts of the United States. Chronic arsenic exposure is associated with increased risk for skin, liver and bladder cancers, skin lesions, cardiovascular disease, and other adverse health outcomes.
      The researchers found that treatment with 400 micrograms a day of folic acid, the U.S. recommended dietary allowance, reduced total blood arsenic levels in the study population by 14 percent. Folate, a B vitamin found in leafy vegetables, citrus fruits, beans, and whole grains, can also be taken as a vitamin supplement and in the United States is added to flour and other fortified foods. The researchers found that folate deficiency is very common in Bangladesh, where the study was conducted.
      “Folic acid supplementation enhanced the detoxification of arsenic to a form that is more readily excreted in urine,” says Mary Gamble, Ph.D., assistant professor of environmental health sciences at the Mailman School and lead author. The study is jointly supported by the National Institute of Environmental Health Sciences and the federally funded Superfund Basic Research Program.
      “The technology to measure arsenic in blood, and particularly to measure the individual arsenic metabolites in blood, didn’t exist when the studies were first planned,” Dr. Gamble says. She credits the advanced technology to advances in other Columbia labs, such as work conducted by Superfund grantee Joseph H. Graziano, Ph.D., professor of environmental health sciences at the Mailman School and study co-author.
      The study suggests that folic acid supplementation may help reduce body stores of arsenic even after exposure has been reduced. Elevated risk for adverse health outcomes persists for decades after exposure has been eliminated. The researchers stress, however, that additional studies are needed to determine the optimal dose and duration of treatment, as well as studies that include health outcomes.
The study, “Folic Acid Supplementation Lowers Blood Arsenic,” is in Am J Clin Nutr 86:1202-1209 (2007).