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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #175699
Title: APPROPRIATE USES OF VITAMIN A TRACER (STABLE ISOTOPE) METHODOLOGY

Author
item FURR, HAROLD - CRAFT TECHNOLOGIES
item GREEN, MICHAEL - PENNSYLVANIA STATE UNIV
item HASKELL, MARJORIE - UNIV OF CALIFORNIA-DAVIS
item MOKHTAR, NAJAT - INTL ATOMIC ENERGY AGENCY
item NESTEL, PENELOPE - HARVESTPLUS
item Ribaya-Mercado, Judy
item TANUMIHARDJO, SHERRY - UNIV OF WISCONSIN-MADISON
item WASANTWISUT, EMORN - MAHIDOL UNIV, THAILAND

Submitted to: International Lifesciences Institute Report
Publication Type: Monograph
Publication Acceptance Date: 10/1/2004
Publication Date: 11/1/2004
Citation: Furr, H., Green, M., Haskell, M., Mokhtar, N., Nestel, P., Ribaya-Mercado, J., Tanumihardjo, S., Wasantwisut, E. 2004. Appropriate uses of vitamin A tracer (stable isotope) methodology. International Lifesciences Institute Report. [Monograph]

Interpretive Summary:

Technical Abstract: Vitamin A deficiency (VAD) is a nutritional health problem of great public health significance in developing countries. Traditionally, clinical eye signs of xerophthalmia are used to determine whether a population group is vitamin A deficient. However, thousands of children would need to be examined to determine the population prevalence of xerophthalmia. Biochemical or marginal deficiency, in which clinical eye signs are absent, is more prevalent and also has negative consequences on human health. Serum retinol concentration is the most commonly used biochemical technique, but it is only useful at the population level. Moreover, because serum retinol is homeostatically controlled and negatively affected by subclinical infection, it is not an optimal indicator for assessing the change in vitamin A status in response to an intervention. The tracer dilution technique is the only indirect assessment technique that provides a quantitative estimate of total body vitamin A pool size. Because the technique is responsive to food or pharmaceutical supplementation with vitamin A, it can be used to evaluate the efficacy or effectiveness of intervention programs by assessing quantitatively the change in total body vitamin A stores. Further, unlike other indicators (e.g., clinical signs of xerophthalmia, serum retinol, breast milk retinol, dose response tests), the technique can estimate total body vitamin A from the range of deficient to sub-toxic levels. Vitamin A tracer studies have been successfully applied for assessing vitamin A status of populations, and the efficacy and effectiveness of interventions in population groups at risk of VAD. It is the method of choice when a quantitative estimate of vitamin A pool size is important and when critical decision-making is needed. The technique can be used to estimate quantitatively the amount of vitamin A retained in the body in response to supplementation with different dietary sources of vitamin A, and to estimate the relative impact of consumption of these foods on total body vitamin A stores. Although tracer methodology is a powerful tool for assessing vitamin A status and the efficacy and effectiveness of interventions, the costs are not trivial. However, the sample size required are usually much lower than the sample sizes required for other indirect assessment techniques.