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United States Department of Agriculture

Agricultural Research Service

Title: Review of the magnitude of folate and vitamin B12 deficiencies worldwide

Authors
item Mclean, Erin - NUTR.& HEALTH WHO, GENEVA
item Benoist, Bruno DE - NUTR.& HEALTH WHO, GENEVA
item ALLEN, LINDSAY

Submitted to: Food and Nutrition Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 2007
Publication Date: April 1, 2008
Citation: Mclean, E., Benoist, B., Allen, L.H. 2008. Review of the magnitude of folate and vitamin B12 deficiencies worldwide. Food and Nutrition Bulletin. 29(2):S38-S51.

Interpretive Summary: The World Health Organization (WHO) has prepared the first global estimates of the prevalence of folate and vitamin B12 deficiencies. This article describes the criteria and process applied for existing data to be entered into the WHO data bank. Data were compiled from existing articles, reports and surveys. Folate and vitamin B12 status were assessed most often in women of reproductive age (34 countries) and other adults (27 countries). The information includes serum concentrations of both vitamins, red blood cell folate, and metabolic markers of status including homocysteine and methylmalonic acid.

Technical Abstract: Human deficiencies of folate and vitamin B12 result in adverse effects which may be of public health significance, but the magnitude of these deficiencies is unknown. Therefore, we examine the prevalence data currently available, assess global coverage of surveys, determine the frequency with which vitamin status assessment methods are used, and identify patterns of status related to geographical distribution and human development. Surveys were identified PubMed and the Vitamin and Mineral Nutrition Information System at the World Health Organization (WHO). Since different thresholds were frequently used to define deficiency, measures of central tendency we used to compare blood vitamin concentrations among countries. The percentage of countries with at least one survey is highest in the WHO Regions of South-East Asia and Europe. Folate and vitamin B12 status were most frequently assessed in women of reproductive age (34 countries), and in all adults (27 countries), respectively. Folate status assessment surveys assessed plasma or serum concentrations (55%), erythrocyte folate concentrations (21%), or both (23%). Homocysteine was assessed in one-third of the surveys of folate and vitamin B12 status (31% and 34% respectively), while methylmalonic acid was assessed in fewer surveys of vitamin B12 status (13%). No relationship between vitamin concentrations and geographical distribution, level of development, or population groups could be identified, but nationally representative data were few. More representative data and more consistent use of thresholds to define deficiency are needed in order to assess whether folate and vitamin B12 deficiencies are a public health problem.

Last Modified: 9/29/2014
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