Submitted to: Nutrition Reviews
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2007
Publication Date: 5/10/2009
Citation: Allen, L.H. 2009. Limitations of current micronutrient status indicators. Nutrition Reviews. 67:S21-23.
Interpretive Summary: Assessment of the prevalence, causes and consequences of micronutrient deficiencies has been a major focus of the public health nutrition community over the past two decades. However, there are still considerable limitations to the available indicators of micronutrient status. The available indicators can be categorized as: measures of anemia and hematological status, including a complete blood count; levels of nutrients and metabolites in blood, urine and breast milk; indicators of body stores, such as ferritin or the transferrin receptor: ferritin ratio for iron stores, and the modified relative dose response (MRDR) test for liver retinol stores; and the prevalence of inadequate intake of each micronutrient, obtained by comparing intakes to the Estimated Average Requirements.
Technical Abstract: Even though assessment of micronutrient status is a major concern in public health nutrition, there are serious limitations to the available indicators. These include cost, lack of congruence between cut-offs used to denote deficiency and adverse functional consequences, and inconsistent methods of dealing with the confounding effect of infections on micronutrient status indicators. Methods to assess the functional consequences of micronutrient deficiencies are even less well developed, and not focused on outcomes known to be sensitive to deficiencies. Notable breakthroughs in the development of indicators include ability to measure several indicators simultaneously in small samples of blood or serum dried on filter paper, the use of change in body stores of iron or vitamin A to assess bioavailability and efficacy or effectiveness of a micronutrient intervention, and calculation of the prevalence of micronutrient intakes below the Estimated Average Requirement. Further improvements in methods to assess micronutrient status are needed urgently.