Monitoring and evaluating efficacy and effectiveness of fortified food-based interventions using isotopic and nuclear techniques

Full text: It is recognized that both supplementation and food fortification are effective means to correct nutritional deficiency of micronutrients particularly Fe depending upon the field conditions faced. Although significant progress seems to have been made to identify useful fortificants, the final outcome is dependent upon the type of supplement or fortificant used and the interactions between the nutrients involved as well as cost-effectiveness including the potential to reach large number of people. For many years now, the International Atomic Energy Agency's (IAEA) activities in the human nutrition area have demonstrated the usefulness of nuclear and related isotopic techniques as tools in support of nutritional studies related to micronutrient malnutrition. In dealing with alleviation of nutritional deficiency of Fe, a major concern is the bioavailability of Fe from foods and the method based on administering stable isotopes (isotope 57Fe or 58Fe administered to the subjects through a test meal that is extrinsically labelled) is the only reliable way of measuring the uptake of iron. Since the newly absorbed iron is primarily used for haemoglobin synthesis, iron bioavailability from a specific diet can be determined by measuring the incorporation of an iron isotope into red blood cell haemoglobin 14 days after the ingestion of the test meal. The method is even applicable to pregnant mothers and children. Isotopic techniques have also proven to be very effective in evaluating and monitoring (efficacy and effectiveness of various fortificants) success of food based interventions. The IAEA's experience in Chile covering school-aged children provides a good example. In a feeding study using enriched milk powder as a delivery system and Fe stable isotopes as tracers for monitoring the intervention study, it was found that Fe deficiency anaemia decreased from 30% to less than 5% within a year. As result of this study, the Chilean government has modified its policy for pre-school children nutrition, a programme that covered approximately 1.3 million children. Other examples of IAEA studies involve Indonesia, China and Thailand, which have also shown how isotopic and nuclear techniques yield key data that are useful for strengthening national policies. (author)