The Bug That Causes Malnutrition

Using Nuclear Techniques to Detect Infection and Help Prevent Micro-Nutrient Deficiency

Urea labeled with stable carbon-13 isotopes is dissolved in orange juice to make sure it coats the entire surface of the stomach during the administration of the carbon-13 urea breath test. Orange juice is mixed with the labelled urea to help mask its unpalatable taste. (Photo: S. Henriques/IAEA)

Too little iron in your diet can cause anything from anaemia to heart failure.

Iron is essential to the process of transporting oxygen throughout the body. It's needed for organ and muscle function as well as energy.

Young women who menstruate, pregnant women, new mothers who are breastfeeding and children, are all particularly vulnerable to developing iron deficiency anaemia, either because they're losing iron or because they need more of it than the regular diet can provide.

So for decades governments have been distributing iron supplements to these vulnerable groups, as well as adding iron to foods like flour. This process of adding a mineral like iron or adding a vitamin to food before mass consumption is called fortification.

To test the effectiveness of the fortification process, and to test if iron is being absorbed and metabolised by the body, scientists periodically test a representative portion of the vulnerable population, sometimes using nuclear isotope techniques.

Big Hurdle

The government of the North African nation of Morocco has worked assiduously over the last 10 years to set up its iron fortification programme, train its scientists and millers and set up the necessary infrastructure; all in an effort to improve the population's iron nutrient status.

But all that effort and money might well be for nothing if the population is unable to absorb the iron they're ingesting and convert it into something the body can use.

One of the biggest barriers Morocco faces, along with eating habits and the type of iron used to fortify wheat, is the presence of the bacteria Helicobacter pylori (H. pylori), which some estimate lives in the stomachs of 70% of the population.

Infection with the bacteria can contribute to iron deficiency by causing minor stomach bleeding - this consistent blood loss leading to anaemia - and by making the stomach less acidic, creating a hostile environment for iron, significantly diminishing the body's ability to convert and absorb the essential mineral.

Vicious Cycle

The interaction between malnutrition and infection can be a vicious cycle.

Nutrient deficiencies impair the functioning of the immune system, which can lead to dramatically higher risk of infection. And infections like H. pylori are linked to chronic malnutrition and diarrhoea syndrome in infants and children.

For example, by reducing the amount of gastric acid the stomach produces (removing the gastric acid barrier), H. pylori provides the opportunity for other diseases to take up residence in the stomach, increasing susceptibility to diarrheal disease, a major public health concern linked to malnutrition and growth failure in children in developing countries.

Hygiene and Sanitation

Since H. pylori is mainly contracted when people eat contaminated food or eat with dirty hands, and since it is expensive to treat and the reinfection rate high, the Moroccan government is focusing on preventing new infections in the country's young population by implementing programmes to foster better hygiene. This means ensuring that available food is sanitary, that drinking water is clean, and that people understand the importance of frequent hand washing.

Finding the Culprit

To evaluate the effectiveness of these efforts, the government needs a diagnostic test for H. pylori that is accurate and quick. So they reached out to the IAEA, which is providing expert and financial assistance in Morocco's efforts to implement the carbon-13 urea breath test, a quick and non-invasive test for the presence of H. pylori.

The carbon-13 urea breath test is much like a roadside breathalyzer test administered by the police, except that the patient drinks urea labeled with stable carbon isotopes (13C), which is dissolved in orange juice or citric acid to make sure it coats the entire surface of the stomach, thereby improving the test's accuracy.

If H. pylori is present, it metabolizes the urea, and after 30 minutes, produces carbon dioxide labeled with the stable carbon isotope (13CO2), which can be detected in the breath.

Background

H. pylori is present in all countries, in all parts of the world. More than 50% of the world's population harbor H. pylori in their upper gastrointestinal tract. Beyond its negative effects on nutrition, H. pylori is a major cause of stomach diseases like chronic gastritis, and elevates the risk of developing stomach cancer.

The IAEA has been undertaking research into H. pylori and its consequences for nutrition since 1999, and over the last 15 years, has worked with 25 low and middle income Member States to utilize and implement the carbon-13 urea breath test.

The IAEA is also continuing its research into the effect of H. pylori infection on gastric acid secretion and on iron and zinc absorption in asymptomatic individuals from developing countries. Gastric acid is essential for the conversion and absorption of micronutrients like iron and zinc.

The Agency is also testing a new non-invasive way to measure gastric acid secretion using stable isotopes.

Last update: 10 September 2014