SAN FRANCSICO, CALIFORNIA. Lead poisoning (elevated levels of lead in the blood) is a serious problem in the United States. In 1984 it was estimated that 3-4 million children had lead levels exceeding 15 micrograms/dL (0.72 micromol/liter); significantly higher than the generally accepted safe level of 10 micrograms/dL. Although the elimination of lead additives in gasoline and paint and the phasing-out of lead-soldered cans for foods and beverages have reduced the overall lead exposure, there are still large reservoirs of lead in the soil and in old house paints. The problem is particularly acute in inner city cores and tends to have a disproportionate impact among the poor. Chelation with calcium EDTA is standard treatment for lead poisoning, but some studies have shown that oral chelation with ascorbic acid (vitamin-C) is equally effective. Now medical researchers at the University of California, San Francisco, report a strong correlation between blood levels of ascorbic acid and lead. Their study involved 4,213 youths and 15,365 adults. A total of 0.5 per cent of the youths (aged 6 to 16 years) and 0.4 per cent of adults had elevated lead levels. Among the youths, those with a serum ascorbic acid level of 30 micromol/L or less were 89 per cent likely to have an elevated lead level than were the youths with an ascorbic acid level of 81 micromol/L or more. Among the adults, those with an ascorbic acid level of 15 micromol/L or less were 65 per cent more likely to have an elevated lead level (greater than 20 microgram/L) than were the adults with an ascorbic acid level of 70 micromol/L. The researchers cite several clinical trials in which supplementation with ascorbic acid produced a marked decrease in blood lead levels and recommend further large-scale trials to determine if vitamin C supplementation is an effective means of reducing lead toxicity in exposed population groups. NOTE: This study was partially funded by Hoffmann-LaRoche Inc., a major manufacturer of pharmaceuticals and vitamins.
Simon, Joel A. and Hudes, Esther S. Relationship of ascorbic acid to blood lead levels. Journal of the American Medical Association, Vol. 281, June 23/30, 1999, pp. 2289- 93
Matte, Thomas D. Reducing blood lead levels: benefits and strategies. Journal of the American Medical Association, Vol. 281, June 23/30, 1999, pp. 2340-41 (editorial)