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Folic acid is found in leafy greens like spinach

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Folic acid supplements could be an effective, low-cost way to lower blood arsenic levels in individuals exposed to contaminated drinking water.

The research, conducted in Bangladesh, was published in the October issue of the American Journal of Clinical Nutrition.

Arsenic is a toxic element found naturally in some soils and water. Arsenic exposure has been linked to skin, liver and bladder cancers, skin lesions, cardiovascular disease and respiratory problems.

The study evaluated the blood arsenic levels of 200 subjects before and after taking a 12-week course of folic acid supplements. Folic acid is a B vitamin found in leafy vegetables, beans and whole grains, and deficiency is common in Bangladesh.

The researchers found that a daily dose of 400 micrograms of folic acid reduced total blood arsenic levels by 13.6 per cent.

Lead researcher Mary Gamble, from the US-based Mailman School of Public Health at Columbia University, said that folic acid assists the detoxification of arsenic in the body, helping convert the toxin into a form that the body can more easily excrete.

Subhash Mukherjee, a researcher from Calcutta Medical College in India, said that although the study's results are encouraging, further research is needed on a larger number of people.

Mukherjee said that it remains to be seen whether folic acid could help remove arsenic from the kidney, heart and lungs, and tissues like hair, nails and skin.

Anisur Rahman Khuda-Bukhsh, from India's Kalyani University, warned that folic acid can cause side-effects such as depression, nausea, vomiting and skin rashes, and that it is therefore important to determine the correct dose and course length with the help of a medical professional. 

Chronic arsenic exposure affects about 100 million people worldwide. According to the WHO, up to 60 per cent of people in Bangladesh are at risk from drinking contaminated water.

Reference: American Journal of Clinical Nutrition 56, 1202 (2007)