Zinc deficiency prevalence

These characteristics describe a protean set of disorders whose prevalence is unclear, whose symptomatology may vary from patient to patient and which do not exhibit specific biochemical markers or clinical set points by which to establish their relevance to specific pathological processes. They also point out some of the difficulties which clinicians face in dealing with zinc deficiency syndromes. 

While zinc deficiency syndromes have been known for many years, and their prevalance noted in diverse groups of people world wide, only recently have any identifiable patterns of some of these syndromes been formulated and the underlying mechanisms stated, however tentatively. These syndromes can be complex, present both in children and adults of both sexes and include single or multiple organ systems. These complexities can cause difficulty for both patients and physicians seeking an understanding of these processes. 

Zinc deficiency in humans is widespread throughout the world, though it is more prevalent in areas where the population subsists on cereal proteins. Conditioned Zn deficiency is seen in many disease states. Its deficiency during growth periods results... 

Skin In a prospective study in 78 patients with P-thalassemia aged 10 months to 37 years, skin disorders of any kind were observed in 65 (83%) pruritus and xerosis were the most common (Table 1) [3 ]. Adverse events can occur simultaneously xerosis, for example, was often associated with pruritus. Systemic medication was common in these patients 40 received deferoxamine by slow infusion over 8-12 hours, 5-7 days a week 25 received deferi-prone and 10 received deferasirox. Subcutaneous infusion of deferoxamine is a frequent cause of local reactions, reflected in this series by the occurrence of skin erythema or irritation in 10 patients. Xerosis was less common in those who received deferasirox than in those who received deferoxamine or deferiprone. Xerosis can occur because of iron storage and also in zinc deficiency. The high spontaneous prevalence of a variety of skin disorders in patients with p-thalassemia, as noted in this study, is of interest in the context of attributing skin events to the use of chelating agents. 

Among humans, abnormal dark adaptation is reported in both vitamin A deficiency and zinc deficiency and is especially prevalent in alcoholic cirrhotics (Patek and Haig, 1939 Russell et aL, 1973 Morrison et aL, 1978 McClain et aL, 1979). In the former but not in the latter deficiency, treatment with vitamin A reverses the abnormality (Russell et aL, 1978) only after correcting the zinc deficiency does dark adaptation become normal in the latter case (Morrison et aL, 1978 McClain et aL, 1979). The molecular basis for these observations may be associated, at least in part, with the activity of retinaldehyde reductase in the retina which, as already mentioned, Huber and Gershoff (1975) showed to be especially sensitive to the level of zinc nutriture and Mezey and Holt (1971) showed was competitively inhibited by the presence of ethanol. In the alcoholic cirrhotic, however, the zinc-vitamin A interaction may be further complicated by a defective hepatic synthesis of transport proteins (Mobarhan et aL, 1981) or failure to sequester or retain zinc Nutrition Reviews, 1982) and/or vitamin A (Sato and Lieber, 1981 Leo and Lieber, 1982) in the appropriate tissues. The implications for human nutrition of the interaction of vitamin A and zinc were reviewed by Solomons and Russell (1980). 

Prevalence of Zinc Deficiency in Developing Countries Available Evidence... 

Relatively little information on population zinc status has been collected at the national or subnational level in developing countries. Thus, only very limited estimates of the prevalence of zinc deficiency are available that are based on the proportion of the population with low concentrations of serum zinc or inadequate dietary zinc intakes. Estimates of the... 

Brown KH, Wuehler SE, and Peerson JM (2001) The importance of zinc in human nutrition and estimation of the global prevalence of zinc deficiency. Food and Nutrition Bulletin 22 113-125. 

The prevalence of marginal zinc deficiency in human populations is unknown because of the lack of a good means of assessing zinc status. Measurement of plasma zinc is straightforward, but it does not serve as a reliable indicator of zinc status. Plasma zinc is a quantitatively minor pool that can be easily influenced by minor shifts in tissue zinc. Plasma concentrations do not fall with decreasing dietary intake, except at very low intakes. Plasma zinc can also be affected by factors unrelated to zinc status (e.g., time of day, stress, and infection). Cellular components of blood can be assayed, but erythrocyte concentrations of zinc are maintained in deficient states and variable results have been found with leucocytes. Hair zinc concentrations may reflect available zinc but will also depend on the rate of hair growth. 

During the past two decades, essentiality of zinc for man has been established. Deficiency of zinc in man due to nutritional factors and several dls-seased states, has been recognized. A marginal deficiency of zinc appears to be prevalent in many segments of population in developed countries and more severe deficiencies are widespread in many parts of the world. In our experimental human model, a marginal deficiency of zinc was induced by dietary means. Loss of body weight (less than 10% in six months on zinc restricted diet), testicular hypofunction, hyperammonemia and a decrease in plasma, urinary and neutrophil zinc concentration were observed. Changes in zinc dependent enzymes such as deoxythymldine kinase in newly synthesized connective tissue and plasma alkaline phosphatase were also observed as a result of zinc restriction and repletion in our model. 

The purpose of our study was to produce only a mild zlnc-deflclent state In human volunteers. Inasmuch as severe deficiency of zinc may be llfe-threatenlng, as seen In acrodermatitis enteropathlca. Furthermore, It Is the marginal deficiency of zinc that appears to be prevalent and likely to be missed clinically. Our data show that we were successful In producing a mild zlnc-deflclent state In human volunteers by dietary means. Zinc concentration of plasma, erythrocytes, leukocytes, and urine decreased when the dally Intake of zinc was restricted to... 

Micronutrient deficiencies are one of the most prevalent public health problems affecting more than two billion people worldwide (UNICEF and MI 2004). The magnitude of the problem is much greater in developing countries, where multiple micronutrient (MMN) deficiencies often occur concurrently as a result of poor quality diet. Although vitamin A, iron and iodine are the major micronutrient deficiencies in populations, deficiencies of zinc, vitamin C, folic add and other B vitamins (vitamin B2, Bg, B12 and niacin) are often present simultaneously (Huffman et al. 1999). MMN deficiencies are common throughout the lifespan, but specially in pregnant women and children. Micronutrient defidencies, if left untreated, can have considerable consequences on health and economic development (UNICEF and MI 2004). 

---