Effect of Zamzam water on blood methemoglobin level in young rats

BACKGROUND: Methemoglobin (MetHb) level in blood indicates exposure to nitrogenous compounds. Acquired methemoglobinemia as a result of exposure to nitrates in drinking water is primarily an issue for infants. The amount of nitrates in Zamzam water is said to be on the high side. This study was designed to determine the effect of prolonged use of Zamzam water on MetHb in rat pups. MATERIALS AND METHODS: Wistar rat pups (n = 52, 3 weeks old) were divided into four equal groups. All of them were given normal laboratory chow. The groups differed only in the exclusive source of water, that is ordinary bottled water, standardized mineral water, old Zamzam water (stored since 2008) or fresh Zamzam water. MetHb level was checked (using Avoximeter 4000) at the baseline, and then every week for 4 weeks from blood obtained from retro-orbital sinus. Other parameters tested were total haemoglobin, oxyhemoglobin and carboxyhemoglobin. ANOVA was used to compare the means between the groups. RESULTS: None of the rats in any of the four groups showed any sign of methemoglobinemia or toxicity. Both groups on Zamzam water showed higher increments in their total hemoglobin by the end of the study compared to their baseline (22%) than the ordinary water (9%) and the mineral water (5%) groups. None of the groups showed any significant difference in MetHb levels on intergroup comparison at any of the weekly readings and at the end of the study. CONCLUSION: Prolonged use of Zamzam water did not induce any significant difference in MetHb concentration in rat pups, which might indicate that it is safe for infants.