Rapid Responses to:
|
|
Rapid Responses: Rapid Responses published:
-
![[Read Rapid Response]](/icons/misc/sectionDOWN.gif)
Simultaneous administration of zinc and arsenic enhances arsenic accumulation in tissues
- Mir Misbahuddin, Md. Kamaluddin (14 November 2002)
-
viral or bacterial
- Alessandro Ierman, Piazza dei Campani 13, 00185 Roma Italia (15 November 2002)
-
Re: Simultaneous administration of zinc and arsenic enhances arsenic accumulation in tissues
- Abdullah H Baqui, Robert E Black, Professor and Chairman (26 November 2002)
-
Re: Re: Simultaneous administration of zinc and arsenic enhances arsenic accumulation in tissues
- Mir Misbahuddin, Md. Kamaluddin, MPhil student (3 December 2002)
|
|
|||
|
Mir Misbahuddin, Professor Department of Pharmacology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka, Bangladesh., Md. Kamaluddin
Send response to journal:
|
Simultaneous administration of zinc and arsenic enhances arsenic accumulation in tissues EDITOR- Recently Baqui et al in a randomized trial in rural Bangladesh showed that zinc supplementation in children at a dose of 20 mg/day for 14 days significantly reduced the incidence of diarrhoea and acute lower respiratory tract infection.1 It may be due to improved absorption of water and electrolytes by the intestine2 and faster regeneration of gut epithelium.3 Zinc supplementation is a simple and inexpensive intervention that can be easily used in the developing countries. Daily zinc supplementation for a period of 6 months for the protective effect of diarrhoea is also suggested. 4 Like diarrhoea, in Bangladesh, chronic arsenic poisoning is a big hazard. At present up to 57 million of Bangladesh's 130 million inhabitants are drinking water that contains harmful concentrations of arsenic.5 As a result a large number of people will suffer from cancer within a few years of exposure. Our data using adult male rats show that oral administration of zinc at a dose of 1 mg/kg body weight/day for 1 month is effective in the prevention of arsenic accumulation in different tissues such as spleen, lungs, kidneys, intestine and skin. But it is quite surprising that simultaneous administration of zinc and arsenic increased the accumulation of arsenic in different tissues particularly kidneys and spleen. The cause of which is not known but there may be enhanced absorption of arsenic by zinc. At present, some Bangladeshi physicians prescribe zinc supplementation in the form of syrup to the children as an appetite stimulator. Baqui et al also suggested the incorporation of zinc in the oral dehydration solution.1 If these children drink arsenic simultaneously, which is quite common in Bangladesh, there may be enhanced accumulation of arsenic leading to increased stress condition of the cell and are more prone to the development of chronic arsenic poisoning. In conclusion, one should be careful to prescribe zinc supplementation unless he is ensured that the patient is not taking arsenic at the same time. Mir Misbahuddin, Professor, ______________________ 1. Baqui AH, Black RE, Arifeen SE, Yunus M, Ahmed S, Vaughan JP. Effect of zinc supplementation started during diarrhoea on morbidity and mortality in Bangladeshi children: community randomized trial. BMJ 2002; 325: 1059 (9 Nov). 2. Golden BE, Golden MHN. Zinc, sodium and potassium losses in the diarrhoeas of malnutrition and zinc deficiency. In: Mills CF, Bremner I, Chesters JK, eds. Trace elements in man and animals TEMA 5. Aberdeen: Rowett Research Institute, 1985: 228-232. 3. Bettger WJ, O’Dell BL. A critical physiological role of zinc in the structure and function of biomembranes. Life Sci 1981; 28: 1425-1438. 4. Sazawal S, Black RE, Bhan MK, Jalla S, Sinha A, Bhandari N. Efficacy of zinc supplementation in reducing the incidence and prevalence of acute diarrhea--a community-based, double-blind, controlled trial. Am J Clin Nutr 1997; 66: 413-418. 5. British Geological Survey. Phase 2 groundwater studies of arsenic contamination in Bangladesh. Nottingham: British Geological Survey, 2001. www.bgs.ac.uk/arsenic Competing interests: None declared |
|||
|
|
|||
|
Alessandro Ierman, student Univ la Sapienza Roma, Piazza dei Campani 13, 00185 Roma Italia
Send response to journal:
|
It's a question for your article. Is diarrohea viral or bacterial? Thank you Competing interests: None declared |
|||
|
|
|||
|
Abdullah H Baqui, Associate Research Professor Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA, Robert E Black, Professor and Chairman
Send response to journal:
|
EDITOR - We have read the letter by Misbahuddin and Kamaluddin with a great deal of attention. Since arsenic contamination of the ground water in Bangladesh is the largest naturally occurring mass poisoning in the world, we revisited our recommendation to scale up the therapeutic use of zinc for diarrhoea in view of the findings of Misbahuddin and Kamaluddin to carefully weigh the benefits and possible risks. With an average of 7 days of zinc therapy during each episode of diarrhoea, we demonstrated 24% lower probability of continuing diarrhoea, 15% lower incidence of diarrhoea and a trend suggesting fewer diarrhoea- related hospitalizations. The reduction in duration of both non- dysenteric diarrhoea and dysentery was similar. There was a downward trend of ALRI incidence in the zinc treatment area. The non-injury deaths in the intervention clusters were only about half those in the comparison clusters, which was statistically significant. We were somewhat confused about the findings of Misbahuddin and Kamaluddin. They reported that oral administration of zinc in adult male rats at a dose of 1 mg/kg body weight/day for 1 month is effective in the prevention of arsenic accumulation in different tissues including spleen, lungs, kidneys, intestine and skin. They further reported that simultaneous administration of zinc and arsenic increased the accumulation of arsenic in different tissues, particularly kidneys and spleen. The authors, however, did not mention the dose and duration of zinc and arsenic administration in their trial of simultaneous administration. It is possible that they administered a higher dose of arsenic than the naturally occurring level in the ground water of Bangladesh and administered for a longer period than the average 7 days of intake in our study children. They were not able to explain the reason for the increased accumulation during simultaneous administration. The additional unresolved question is how relevant is this finding in an animal model to Bangladeshi children. In view of our findings of the significant health benefits including large reduction of child mortality from the therapeutic use of zinc during diarrhoea, we reiterate our recommendation to scale up the therapeutic use of zinc for diarrhoea in Bangladesh and elsewhere. We also recommend that while scaling up, the relevance of the finding of Misbahuddin and Kamaluddin is carefully examined. Competing interests: None declared |
|||
|
|
|||
|
Mir Misbahuddin, Professor Department of Pharmacology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka, Bangladesh., Md. Kamaluddin, MPhil student
Send response to journal:
|
EDITOR- To clarify the points raised by Baqui and Black, we would like to mention the dose and duration of zinc and arsenic during simultaneous administration in rats. The dose of zinc was 1 mg/kg body weight/day and the dose of arsenic was 20 microgram/kg body weight/day [8 ~ 10 ml of water containing arsenic (400 microgram/l) was administered orally per day]. Both zinc and arsenic were administered for 1 month. Arsenic concentration of different tissues was also estimated in another group of rats after administration of the same dose of arsenic but no zinc for comparison. Now the question is whether the dose of arsenic used was higher than the naturally occurring level in the ground water of Bangladesh. About one- third of total tubewells’ in Bangladesh contain arsenic on average 500 microgram/l.1 We have found that water of some tubewells contains more than 1,500 microgram/l of arsenic and people are drinking that arsenic contaminated water unknowingly. So, the arsenic concentration in drinking water of rats was within the range that is consumed everyday by millions of Bangladeshi. Arsenic containing water is tasty and people drink that contaminated water in larger volume. The mechanism by which zinc increases the accumulation of arsenic is not known. Like zinc, simultaneous administration of selenium and arsenic may enhance the toxic effects of arsenic, increasing its retention in tissues and suppressing its methylation, which may be a pathway for detoxification of arsenic.2 We, sometimes, depend on the studies on animal models, as there are some limitations about the study in children. 1. Rahman MM, Chowdhury UK, Mukherjee SC, Mondal BK, Paul K, Lodh D, Biswas BK, Chanda CR, Basu GK, Saha KC, Roy S, Das R, Palit SK, Quamruzzaman Q, Chakraborti D. Chronic arsenic toxicity in Bangladesh and West Bengal, India - a review and commentary. J Toxicol Clin Toxicol 2001; 39: 683-700. 2. Styblo M, Thomas DJ. Selenium modifies the metabolism and toxicity of arsenic in primary rat hepatocytes. Toxicol Appl Pharmacol 2001; 172: 52-61. Competing interests: None declared |
|||