Utilizing the Retinol Isotope Dilution Method for Assessing Vitamin A Body Stores and Liver Vitamin A Concentration

TOPICAL COLLECTIONS

Guest Editors

Cornelia Loechl

International Atomic Energy Agency (IAEA)

Dr. Loechl joined the International Atomic Energy Agency (IAEA) in 2010 as a nutrition specialist and has been heading the Nutritional and Health-related Environmental Studies Section since June 2015. Before joining the IAEA, she was a scientist with the International Potato Center (CIP) and a post-doc research fellow with the International Food Policy Research Institute (IFPRI). She has extensive programme management experience which she gained through her work at the World Food Programme and the German Agency for International Cooperation. A German citizen, Dr. Loechl earned her Ph.D. in international nutrition from the University of Giessen, and her M.Sc. in human nutrition from the University of Bonn. Her current research focuses on the use of nuclear and related techniques in nutritional assessment and for monitoring and evaluation of nutrition interventions to combat all forms of malnutrition.

Kenneth H Brown

University of California

Dr. Kenneth Brown is an Emeritus Distinguished Professor in the Department of Nutrition and Institute for Global Nutrition at the University of California, Davis. He completed medical studies at the University of Pennsylvania and trained in Pediatrics at the Boston Children's Hospital Medical Center. Dr. Brown has published more than 390 articles on the causes, complications, treatment, and prevention of childhood undernutrition in lower-income countries, focusing primarily on infant and young child feeding practices, relationships between infection and nutrition, and control of micronutrient deficiencies, including zinc, iron, vitamin A, folate and thiamine. He has served as Founding Director of the research unit in International and Community Nutrition at UC Davis; Founding Chair of the International Zinc Nutrition Consultative Group; Board Member of the MN Forum, committee member of multiple global health organizations and technical expert groups; and editorial board member of several leading nutrition journals. He is a past-President of the Society for International Nutrition Research, Fellow of the American Society of Nutrition and the International Union of Nutrition Sciences, and recipient of the Kellogg Award for International Nutrition Research, the McCollum Award, the Rainer Gross Award, the Suskind Award for Pediatric Nutrition, the Fomon Award of the American Academy of Pediatrics, and the Prince Mahidol Award for nutrition and public health.

Collection Overview

Vitamin A is an essential micronutrient required for normal vision, cellular differentiation, physical growth, immune function, and the synthesis of red blood cells. Severe vitamin A deficiency can lead to corneal destruction and blindness, and subclinical deficiency contributes to infectious disease morbidity and mortality among preschool children, as well as anemia among children and women of childbearing age. At the other extreme of vitamin A status, excessive vitamin A intake imposes a risk of vitamin A toxicity, which can result in birth defects and damage to the liver and bones.

It is essential to consider the complete spectrum of vitamin A status when planning interventions to control vitamin A deficiency and to have accurate information on the population's vitamin A status. Researchers have proposed multiple methods to assess vitamin A status, with the main method being the concentration of retinol in serum, which can only detect vitamin A deficiency. The single practical assessment method that provides information across the full range of vitamin A status, from vitamin A deficiency to hypervitaminosis A, is the retinol isotope dilution (RID) technique.

This Methods Collection will provide detailed guidance on implementing the RID method. It will demonstrate the procedures for preparing the isotope-labeled vitamin A dose, administering it to study participants, and analyzing the labeled vitamin A in blood samples using various analytical platforms. Finally, it will present an overview of different approaches for calculating total vitamin A body stores and liver vitamin A concentrations.