Document Detail


Zinc requirements and the risks and benefits of zinc supplementation.
MedLine Citation:
PMID:  16632171     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The adult human contains 2-3g of zinc, about 0.1% of which are replenished daily. On this basis and based on estimates of bioavailability of zinc, dietary recommendations are made for apparently healthy individuals. Absent chemical, functional, and/or physical signs of zinc deficiency are assumed indicative of adequacy. More specific data are seldom available. Changing food preferences and availability, and new food preparation, preservation, and processing technologies may require re-evaluation of past data. Conservative estimates suggest that 25% of the world's population is at risk of zinc deficiency. Most of the affected are poor, and rarely consume foods rich in highly bioavailable zinc, while subsisting on foods that are rich in inhibitors of zinc absorption and/or contain relatively small amounts of bioavailable zinc. In contrast, among the relatively affluent, food choice is a major factor affecting risk of zinc deficiency. An additional problem, especially among the relatively affluent, is risk of chronic zinc toxicity caused by excessive consumption of zinc supplements. High intakes of zinc relative to copper can cause copper deficiency. A major challenge that has not been resolved for maximum health benefit is the proximity of the recommended dietary allowance (RDA) and the reference dose (RfD) for safe intake of zinc. Present recommendations do not consider the numerous dietary factors that influence the bioavailability of zinc and copper, and the likelihood of toxicity from zinc supplements. Thus the current assumed range between safe and unsafe intakes of zinc is relatively narrow. At present, assessment of zinc nutriture is complex, involving a number of chemical and functional measurements that have limitations in sensitivity and specificity. This approach needs to be enhanced so that zinc deficiency or excess can be detected early. An increasing number of associations between diseases and zinc status and apparently normal states of health, where additional zinc might be efficacious to prevent certain conditions, point at the pharmacology of zinc compounds as a promising area. For example, relationships between zinc and diabetes mellitus are an area where research might prove fruitful. In our opinion, a multidisciplinary approach will most likely result in success in this fertile area for translational research.
Authors:
Wolfgang Maret; Harold H Sandstead
Publication Detail:
Type:  Journal Article; Review     Date:  2006-02-21
Journal Detail:
Title:  Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS)     Volume:  20     ISSN:  0946-672X     ISO Abbreviation:  J Trace Elem Med Biol     Publication Date:  2006  
Date Detail:
Created Date:  2006-04-24     Completed Date:  2006-07-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9508274     Medline TA:  J Trace Elem Med Biol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  3-18     Citation Subset:  IM    
Affiliation:
Department of Preventive Medicine and Community Health, Division of Human Nutrition, University of Texas Medical Branch, 700 Harborside Drive, Galveston, TX 77555, USA. womaret@utmb.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Dietary Supplements* / adverse effects
Dose-Response Relationship, Drug
Female
Humans
Male
Nutritional Requirements
Risk Assessment
Risk Factors
Sex Factors
Zinc* / adverse effects,  deficiency,  therapeutic use
Chemical
Reg. No./Substance:
7440-66-6/Zinc

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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