Effect of vitamin C supplementation on body leads in children A.H. Gilani, S.A. Tariq, A.J. Shah, S.A.H. Zaidi, Z.A. Butt and M.N. Ghayur. Department of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi, Pakistan.

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Lead is one of the toxic metals present in the environment and constant exposure from air, water and food adversely affects our health. Children are at high risk because lead exhibits toxicity even in low concentrations, producing intellectual and behavioural problems, quite common in large cities, like Karachi (Rahbar et al., 2002). However, there is hardly any satisfactory and safe remedy, particularly for chronic lead toxicity (Klaassen, 1996). We describe here, the results of a preliminary study showing that Vitamin C has a potential to detoxify lead in school children.

Urine and hair samples were collected from a group of 8 school children, ranging from 7 to 12 years, before initiating any treatment. Each child was then given a 500 mg Vitamin C tablet orally (obtained from the Aga Khan University pharmacy) after dinner every night for 24 days. Urine samples excreted during the night and following early morning were collected daily. Hair samples were obtained again after vitamin C treatment at the end of 24 days.

A measured volume of each urine sample was digested with 10 ml of 65 % concentrated nitric acid and heat application of 110ºC, reducing the volume below 50 ml. After cooling to room temperature, volume of the resulting solution was made up to 50 ml. Each hair sample was accurately weighed, transferred into a beaker and heated with 10 ml of 65 % concentrated nitric acid until brown fumes of nitrogen dioxide subsided. The beaker was continuously heated until aclear solution was formed, then cooled to room temperature and solution transferred to a 50 ml standard flask. The volume was made to mark with water. Lead concentrations in each solution were determined using an Atomic Absorption Spectrometer (Perkin Elmer A Analyst 300) at the Chemistry Laboratory of the Geological Survey of Pakistan, Karachi.

The mean lead concentration in hair, before giving Vitamin C was 12.7 ± 7.1 µg g^-1 (mean ± s.d.; n=8), which after treatment with Vitamin C was reduced to 3.7 ± 3.6 µg g^-1 (P< 0.05, paired t-test). Urine analysis before giving Vitamin C indicated that 6 out of 8 samples had lead concentration less than 0.1 mg l^-1 (undetectable based on single collection), whereas in the remaining two samples, lead level were found to be 0.1 mg l^-1, hence the mean value of samples was considered less than 0.1 mg l^-1. Lead concentration in 1^st urine sample (based on 1^st three days collection after treatment) was 4.5 ± 3.2 mg l^-1, which was at least 45 times higher than the lead level before treatment. However, lead concentration in the subsequent three samples based on weekly collections were significantly reduced to 0.07 ± 0.03, 0.08 ± 0.01 and 0.09 ± 0.02 mg l^-1 respectively, which are close to control values.

These data clearly indicate that the treatment with Vitamin C reduces body lead level through excretion of urine by probably forming a water-soluble complex (lead-ascorbate). This study has an important public health implication, especially for children around the world.

Klaassen, C.D. (1996). In The Pharmacological Basis of Therapeutics, Hardman, J.G. et al., eds,9 ^th edn, pp.1649-1671, New York, McGraw-Hill.
Rahbar M.H, et al. (2002). Bull. World Health Organ., 80, 769-775.