Vitamins and minerals are vital in a child´s diet to boost immunity and healthy development. Too often, young children´s health and immunity are threatened by malnutrition and infections, creating a vicious cycle of infection exacerbating malnourishment. Although an infectious disease is often listed as the cause of death, malnutrition plays a crucial role in more than half of the 10.6 million annual deaths of children under five.
Great strides have been made in our understanding of nutritional interventions that can contribute to the prevention and treatment of infections. But there is still much to discover about the best ways to provide optimal nutrition to infants and children threatened by infectious diseases.
For example, research has demonstrated that supplementing young children´s diets with zinc effectively improves the standard treatment for diarrhea. Increased intake of both zinc and vitamin A has been proposed to benefit young children exposed to infections such as tuberculosis. In contrast, some children exposed to malaria have had mixed reactions to nutrition supplements with iron.
Although the idea is counterintuitive, could an increased intake of some nutrients make a child more susceptible to some infections?
Iron Deficiency and Malaria
Children in the developing world commonly experience micronutrient deficiencies, such as too little iron in their diets. As a result, iron supplements have been routinely recommended in the past to correct this deficiency. In many African countries the problem is compounded by malaria, which kills about one million children each year. Malaria is caused by parasites that are transmitted through the bites of infected mosquitoes.
Research in regions affected by malaria has indicated that, although iron-deficient children are helped by routine iron supplementation, children who already have enough iron are at an increased risk of becoming ill when they are given iron supplements.
"So, the important question arises: could giving extra iron, either in the diet or as supplements in tablets make malaria worse?" says Bernard Brabin, Professor in Tropical Paediatrics at the Liverpool School of Tropical Medicine in England.
"It´s possible that the parasite can reach higher densities if there is more iron in the blood. So giving iron might lead to feeding the parasite and making the malaria worse. And that´s where the IAEA comes in,"" says Brabin.
Stable isotope technique can be used to estimate the amount of absorbable iron in the body, and a better understanding of iron absorption can help researchers understand the potential risk of infection.
"Iron is everywhere and it´s essential to normal health, and yet there seems to be this fine balance between having too much and having too little," says Brabin. "One of the difficulties is that you can´t actively excrete iron from the body. Normally, if you have too much of something the body switches a mechanism on and helps you excrete it so you come back into balance. That doesn´t happen with iron. So what you take in - if you absorb it - you retain it.
"The balance is very finely tuned and when you interfere with that balance by giving extra iron, you have to be absolutely sure that it´s safe. And really, that is the bottom line - is it safe?"
To fill the gaps in our scientific knowledge, the IAEA has begun an international project which aims to develop ways of improving the nutrition of infants and young children who are at high risk of infectious diseases such as malaria and tuberculosis.
This will be accomplished by applying state-of-the-art stable isotope methods to evaluate the absorption of micronutrients such as iron and zinc or to assess body composition and vitamin A reserves.
"These are specialised techniques that not many researchers use, and so the IAEA´s support for these studies is extremely important," says Nancy Krebs, Professor of Paediatrics at the University of Colorado-Denver´s School of Medicine.
"It´s one thing to give infants a dose of iron or a dose of zinc and then follow them for a year and see how many of them get sick. But that does not really tell you, if they were healthier at the end of that year, why they were healthier. Whereas the isotope studies give us more insight into how the body was actually using those supplements or those micronutrients that were being given."
New data, published as peer-reviewed scientific reports, will help to contribute to the development or monitoring of the best nutritional practices to manage the nutrition of infants and children who are at high risk of infectious diseases.
The role of micronutrients to help prevent or treat infectious diseases in children is being investigated in seven countries: Bangladesh, Burkina Faso, Kenya, Malawi, Pakistan, Tanzania and Vietnam.
In addition, experienced investigators from Switzerland, the United Kingdom, and the United States are contributing to the project´s planning and implementation.
This work is funded solely by the IAEA in some countries, while in others, IAEA-sponsored stable isotope research is part of larger clinical trials sponsored by organizations such as the Bill and Melinda Gates Foundation.