Zinc Deficiency and Clinical Practice - 日本医師会

1 JMAJ, August 2004 Vol. 47, No. 8359 This article is a revised English version of a paper originally published inthe Journal of the Japan Medical Association (Vol. 129, No. 5, 2003, pages 613 616).IntroductionThe number of patients visiting outpatientclinics with complaints of abnormal sense oftaste or olfaction (most frequently reduced orabnormal sense of taste) has been on ,2) It has been estimated that about140,000 new patients with such complaints areregistered annually,2) and that about 30% ofthese patients have dietary zinc ,2) zinc Deficiency and Clinical PracticeJMAJ 47(8): 359 364, 2004 Hiroyuki YANAGISAWAA ssociate Professor, Department of Hygiene and Preventive Medicine,Saitama Medical SchoolAbstract.

2 In recent years, the number of patients visiting outpatient clinics withcomplaints of abnormal sense of taste or olfaction has been on the increase. It hasbeen estimated that about 30% of these patients may have dietary zinc deficiency is more likely to develop among children whose daily requirementsof zinc are greater, among elderly people whose dietary consumption of nutrientsis poor, and among young women who are often on diets for weight reduction. Zincdeficiency may be associated with features such as hypogeusia, hyposmia, growthretardation, dermatitis, alopecia, compromised gonadal function, susceptibility toinfections, and delayed wound healing.

3 At present, measurement of the serum zinclevel is considered to be the most reliable means of diagnosing zinc deficiency. Ithas been proposed that if the serum copper level were also measured, then theratio of the serum copper to zinc level (serum copper/ zinc ratio) can be used asreference information for diagnosing zinc deficiency. For the treatment of zincdeficiency, zinc replacement therapy at a daily zinc dose of about 30 mg is con-sidered to be relatively safe. However, further study of the safety and adverseeffects of zinc replacement therapy is words: zinc ; Essential trace elements; DeficiencyZinc is known to serve as the active center ofabout 300 enzymes, and is an essential traceelement in humans (Table 1).

4 1)It has been reported that the amount ofzinc ingested per day may be insufficient rela-tive to the daily requirement in some groupsof individuals (children, elderly people, youngwomen on weight-reducing diets, and someother groups). These individuals may developquasi-deficiency or true deficiency of ,2) In Trace Elements360 JMAJ, August 2004 Vol. 47, No. 8are induced by post-natal factors (Table 2).1)Acquired zinc deficiency is often attributableto extreme deficiency of nutrients includingzinc, or extremely unbalanced diets (insuffi-cient ingestion of animal proteins rich in zinc ).

5 The most frequent causes of zinc deficiencyare prolonged high-calorie parenteral therapyand enteral nutrition. Long-term high-calorieparenteral therapy inevitably induces zincdeficiency. To avoid its occurrence, IV solutionadditives containing 5 trace elements (iron, paper, we shall briefly discuss the etiology, Clinical symptoms, and the methods of diagno-sis and treatment of zinc deficiency, a conditionthat has recently drawn much deficiency can be divided into congenitaland acquired types of zinc deficiency. Acro-dermatitis enteropathica, an inherited abnor-mality of zinc absorption, is rare.)

6 Most casesTable 2 Major Causes of zinc Deficiency1. Inadequate intake3. Excessive loss1) Low- zinc -containing diets:1) Loss into digestive fluid:Foods poor in animal protein (vegetarians)Child intractable diarrhea, intestinal fistula,2) Loss of zinc during food processinggastrointestinal disease associated with diarrhea(desalting during production of artificial milk)2) Increased urinary elimination:3)Prolonged intravenous alimentation,Liver cirrhosis, diabetes mellitus, renal disease,enteral alimentationhemolytic anemia, intravenous alimentation,4) Shortage of nutrient intakeenhanced catabolism (surgery, trauma, infection, etc.

7 ,2. Malabsorptiondiuretics, sodium polyphosphate1) Congenital:Acrodermatitis enteropathica (very rare)3) Others: Burns, hemodialysis2) Acquired4. Increased demand(1) Ingestion of absorption inhibitors:Pregnancy, neonates (premature babies),Phytic acid, edible fibersenhanced anabolism (during intravenous alimentation, etc.)(2) Malabsorption syndrome:Liver dysfunction, pancreatic dysfunction,5. Unexplainedinflammatory bowel disease, short bowel syndromeCongenital thymus defect, Mongolism(3) Drugs, chelating agents: EDTA, penicillamine*Underlined particularly importantSource: Yanagisawa, H.: Clinical aspects of zinc deficiency.

8 The Journal of the Japan Medical Association 2002; 127 (2): 261 , H. et al.: zinc Extensive blood and urine biochemistry and immunological tests (2). Japanese Journal ofClinical Medicine 1999; 57 (extra issue): 282 1 zinc and Its FunctionsEssentialtrace elementTargetFunctionCarbonic anhydrase, peptidase, alcohol dehydrogenase,alkaline phosphatase, polymerase, superoxide dismutase (SOD),angiotensin-converting enzyme, collagenase,Cell division, zinc -aminolevulinic acid anhydrase, protein kinase C,nucleic acid metabolism,phospholipase C, aspartate transcarbamylase,co-enzymesnucleotide phosphorylase (5 -nucleotidase), RNase, : Yanagisawa, H.

9 : Clinical aspects of zinc deficiency. The Journal of the Japan Medical Association2002; 127 (2): 261 , August 2004 Vol. 47, No. 8361 zinc DEFICIENCY zinc , copper, manganese, and iodine), thathave recently become available commercially(including Elemenmic (Ajinomoto Pharma Co.,Ltd.) and Mineralin (Nihon PharmaceuticalCo., Ltd. and Takeda Chemical Industrials,Ltd.), may be used. The use of these additiveshas reduced the apparent incidence of zincdeficiency. Although these 5 trace elements arealso contained in preparations used for enteralnutrition, zinc deficiency can develop if theamount of zinc in the diet is insufficient rela-tive to the requirement, or if the patients havesuch conditions as malabsorption, diarrhea, orintestinal fistula.

10 Furthermore, zinc deficiencycan be induced by continued use of low-mineral purified foods (minerals are lost duringpurification), foods containing additives withchelating activity (sodium polyphosphate, phyticacid, or EDTA [which is also used as a drug]),and drugs which can disturb the sense of taste(about 170 such drugs are known, and many ofthem have chelating activity2)).1,2)Regarding the relationship of zinc deficiencywith age, the deficiency is more likely to developduring childhood, when the daily requirementof zinc is higher, in adult women (especiallyyoung women on weight-reducing diets), andin elderly people whose dietary consumption ofnutrients is poor.