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Nuclear Techniques Help Explain the Various Dimensions of Malnutrition among Children in Botswana


Saliva sampling exercise with a child for body composition assessment. (Photo: V. Owino/IAEA)

Despite strong economic growth in Botswana over the last two decades, malnutrition has not declined as significantly as in other countries at similar stages of their development. Isotopic techniques can help change that.

Several key indicators related to child nutrition illustrate the current situation well. In 2019, the proportion of children below five years of age who were too short for their age was 31.4%. Almost 5% of these children were also too thin for their height, a condition known as wasting, which is associated with increased risk of death. About 16% of newborn children weigh too little at birth, setting them up for stunting and heightened risk for overweight and obesity later. Anemia, a condition that can lead to the body’s tissues not being supplied with enough oxygen, is also rampant, affecting over 40% of all children below five years of age, a situation that is exacerbated by endemic infectious diseases, mainly malaria.

At a recent workshop in Botswana designed to tackle malnutrition, Martin Kebakile, the Managing Director of National Food Technology Research Centre (NFTRC), noted the importance of evidence-based interventions to address the plethora of nutritional challenges facing Botswana. “If you can’t measure it, you can’t understand it and therefore do anything about it,” said Kebakile. He added that through strong collaboration with the IAEA, Botswana now had the capacity to use stable isotope techniques to address nutritional problems. He noted that capacity building is a key starting point and that Botswana can be a working model for the rest of the region.

The government has been running a nutrition supplementation programme for four decades in which an iron-fortified sorghum-soybean porridge flour, popularly known as tsabana, is distributed among children aged 6-36 months to promote growth and reduce anemia. Since 2016, NFTRC has received support from the IAEA, through its technical cooperation programme, to develop capacities in using stable isotope techniques to evaluate this initiative, with a focus on the children’s iron status.

Key findings from a first phase study under the national project were shared at the workshop, held at the NFTRC premises from 24-28 February, with more than twenty participants from the Ministry of Agriculture, Botswana Defense Forces, Botswana Bureau of Statistics, universities, local hospitals and the Kanye District Health Management Team. The study found that children from high malaria-prone areas were more wasted, while those with elevated markers of inflammation were more stunted. Using the deuterium dilution technique to measure body composition, it was shown that stunted children had lower fat-free mass, an indication of general tissue loss.

The deuterium dilution technique is state-of-the-art methodology to assess body composition and thus provides a tool to evaluate the effects of altered diet and physical activity on adiposity. A person drinks a weighed amount of water, that is labelled with deuterium, a stable isotope of hydrogen. The water is labelled but is non-radioactive and therefore has no adverse health consequences. After a few hours the isotope in the labelled water is evenly spread throughout the body water, which can be sampled in the form of saliva or urine. Deuterium enrichment in saliva is measured using an FTIR or an isotope ratio mass spectrometer (IRMS). Since the amount of deuterium is known, the total volume of body water can be calculated from the enrichment. Based on the assumption, that fat is water-free, scientists can accurately determine the body’s ratio of fat and fat-free tissue. This nuclear technique is accurate and safe to use in all age groups, it is not associated with any radiation hazard, and is suitable for the use in field settings.

Other findings showed that although tsabana has been distributed for almost 4 decades, anemia rates have not gone down. Boitumelo Motswagole, Director of Research and Development, NFTRC, presented evidence from a sample of 200 children that indicates that the high prevalence of anemia among the children (47%), is not only related to iron deficiency, but also to infections, such as malaria.

A larger confirmatory study has commenced, also supported by the IAEA. Four hundred children will be included and further indicators of iron status will be assessed. This phase of the project will also employ iron stable isotopes to measure how much of the iron in tsabana is absorbed for use by the body after consumption. These results will inform the choice of the iron compound added to tsabana as this is an important determinant of how much iron is absorbed from the porridge when it is consumed by children.

“Thanks to this workshop, we can now use these techniques to understand the importance of body composition and its relation to malnutrition,” said DK Mokgwathi, Director of Research and Development, Botswana Defence Forces. “It is through events such as this one that an ecosystem for networking is born, enabling the cooperation necessary to make malnutrition a problem of the past and to give hope to both the living and the unborn.”

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