Notes from the field
Dec 18, 2012 by Rebecca Day Merrill
Listed In: Water & Health
In rural Bangladesh, tubewells, the most common source for domestic water, often provide water naturally containing minerals, including substantial amounts of iron in some areas. Recent research conducted at the JiVitA Project in rural north-west Bangladesh by researchers from Johns Hopkins University found that drinking iron-rich tubewell water can reduce the risk of iron deficiency by improving the body’s iron stores.
Anemia is a major health problem among mothers and children in Bangladesh and is the focus of many public health interventions. The condition, characterized by a low hemoglobin concentration, can lead to fatigue, weakness, and many other health problems, particularly during demanding phases of growth and pregnancy. It is widely assumed that anemia is due predominantly to iron deficiency, especially in resource-poor settings where diets often lack adequate amounts of iron and supplement use is low. However, iron deficiency may not always be the leading cause of anemia. Understanding the local environment can help with the daunting task of unraveling the causes of this condition.
Across Bangladesh, tubewell use is ubiquitous resulting from an initial effort during the International Drinking Water Decade of the 1980s to install thousands as a way to reduce the use of pathogen contaminated pond and river water. As a result, currently over 90 percent of the Bangladeshi population uses a household tubewell for drinking and cooking water needs. The groundwater pumped from such wells is often naturally rich in minerals reflecting the mineral composition of the underground environment from which it is collected. A great amount of attention has focused on the alarming arsenic levels, but other minerals such as iron can also be elevated in the country and surrounding region.
A study-wide groundwater survey of the JiVitA Project site in rural north western Bangladesh revealed an environment with elevated and variable groundwater iron concentration with a mean value of 16.7 mg/L, a level over 50 times the World Health Organization (WHO) defined (aesthetic) limit of 0.3 mg/L (1). It is widely believed that iron in water used for drinking and cooking is not an effective dietary source of iron because, among other reasons, when in water the mineral is present in a form not easily absorbed by the body. This assumption is based on a well understood pathway by which iron is found in the ferrous, easy to absorb form when first pumped but upon exposure to air, it immediately begins to react with oxygen to form ferric, rust-like iron that is not easily absorbed. The density of tubewell availability in Bangladesh means that many do not have to walk more than 15 meters to collect water and water is often consumed within a few minutes of pumping from a tubewell. This typical use pattern suggests that consumers are drinking water before it has adequate time to react to oxygen in the air allowing iron to remain in a ferrous, easily absorbed form. To address this, we used additional water characteristics measured at the same time as iron concentration assessment to estimate that the dominant form of iron in the water, as it is pumped from the ground, is ferrous suggesting that the iron could be easily utilized by the body.
Subsequent to the study area-wide groundwater survey, we implemented additional research to explore the influence on women’s iron status of drinking naturally iron rich groundwater. This study involved two repeat seasonal data collection rounds that each involved groundwater analysis of the household tubewell used to collect drinking water and an interview to a woman of reproductive age living at that household to gather information not limited to diet and typical groundwater collection and consumption habits. The results from this activity revealed that half of the participants consumed more than 42 mg of iron every day from their drinking water alone. Further, 47 percent of women were consuming at or above the daily tolerable upper intake level of 45 mg of iron, before accounting for iron in their food, a level above which health risks in a general population increase. Although daily intake levels were elevated, there was no sign of women experiencing iron overload, suggesting that their bodies are able to adjust to the iron intake levels.
Most notably, groundwater iron intake from drinking significantly improved iron stores and helped women avoid iron deficiency. As such, where iron-rich tubewell water was consumed, low iron status was not the apparent cause of anemia which was still highly prevalent at 57 percent (2). Instead, anemia may have resulted from deficiencies of other micronutrients, genetic conditions (e.g., thalassemia or other hemoglobinopathies), or infectious diseases (3).
The findings from the JiVitA Project suggest that assessing iron in tubewell water could be an important part of evaluating diet and nutrition in rural communities where groundwater is consumed. Further, they imply that in settings with high levels of iron in water, routine iron supplementation may not be helpful in treating anemia. Taken together, these results point to the importance of a systems wide approach, which in this case involves dietary, environmental, and genetic considerations, when addressing public health issues.
Keywords: Groundwater, diet, iron, anemia, women, Bangladesh
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