“You are what you eat,” the old saying goes, and those getting a limited variety of nutrients in their diet can expect poor health. For decades, governments and NGOs around the world have been battling this problem by promoting supplements and foods fortified with nutrients including vitamin A. Concerns, however, are now being raised about whether uncoordinated, overlapping schemes are causing too much of a good thing — that is, a bad thing — and harming people’s health.
A recent IAEA technical meeting explored these concerns, bringing to the forefront a technique using stable isotopes that can with great accuracy help nutritionists and public health professionals better understand the vitamin A status in populations exposed to several programmes addressing vitamin A deficiency (See Using isotopes to measure Vitamin A status).
Vitamin A is an organic compound that’s important for growth and development. It helps maintain your immune system and is essential for good vision. Getting enough vitamin A isn’t within reach for everyone, since the biologically active form occurs only in a few animal products such as eggs, dairy products and liver. More accessible foods such as orange-fleshed fruits and vegetables like mangoes, pumpkins and carrots as well as green leafy vegetables contain carotenes, which can be converted to vitamin A in the body.
Unlike vitamin C, or other water-soluble nutrients, vitamin A is fat soluble. That means once ingested it does not leave the body quickly and accumulates in the liver — potentially damaging it and causing symptoms similar to those of alcoholism, like yellowing of the white part of the eyes.
The World Health Organization (WHO) classifies vitamin A deficiency as a public health problem and estimates that, globally, 190 million children under the age of five are affected. Their data suggests 800,000 deaths can be attributed annually to vitamin A deficiency. Many countries have therefore been administering high-dose vitamin A supplements with immunization services, but this does come with some risks if other vitamin A programmes are in place. Studies in South Africa, Philippines and Guatemala suggest that some population groups may be getting too much of vitamin A due to overlapping supplementation and fortification programmes coupled with improved diets.
