Approach
Initial treatment is with oral zinc supplementation. Parenteral zinc supplementation is rarely necessary.
Owing to the relatively low sensitivity of serum zinc levels in marginal deficiency, oral supplementation should be considered if symptoms are typical, even if test results are normal. In patients at high risk, empirical supplementation should be considered.
Other nutrient deficiencies often co-exist with zinc deficiency (e.g., iron, vitamin D), and these should also be sought and supplemented if deficient because zinc repletion alone may not lead to significant clinical improvement.[56] Zinc and iron supplementation can be given in combined form or separately, though there is some evidence that separate formulations are more effective in children with stunting of growth.[57]
For people with acquired zinc deficiency, focus on amelioration of the predisposing condition is required. In acrodermatitis enteropathica, zinc supplementation is lifelong.
Zinc supplementation
Although the recommended daily intake for zinc is relatively low, standard supplementation is approximately 20 to 40 mg/day orally for adults.[58]
Recommended daily zinc (elemental) intake: NIH Office of Dietary Supplements fact sheet for health professionals: zinc Opens in new window
3 mg/day for children <4 years
5 mg/day for children 4 to 8 years
8 mg/day for children 9 to 13 years
9 mg/day for non-pregnant and non-lactating adult women
11 mg/day for adult men
11 to 12 mg/day in pregnancy and lactation.
Higher doses of zinc (>50 mg/day) may be needed acutely in patients with severe deficiency due to malnutrition or chronically in patients with irreversible malabsorptive disorders including Crohn's disease or short bowel syndrome.
At doses >50 mg/day, gastrointestinal (GI) symptoms including nausea, abdominal discomfort, and diarrhoea are common, whereas doses >150 mg/day may adversely affect immune status, lipid profile, absorption of iron and copper, and can cause genito-urinary problems.
When supplementing zinc for longer periods of time, especially at high doses, it is useful to monitor the serum/plasma copper status. During long-term zinc supplementation‚ or in documented cases of copper deficiency, copper supplements can be given.
Various formulations of zinc supplements are available and may include zinc sulfate, zinc acetate, and zinc gluconate. Typical doses are safe when used long-term. Patients should be monitored for improvement in symptoms and their serum zinc levels checked after 3 to 6 months of therapy. If repletion is not noted, zinc intake may be increased; however, patients should be monitored for toxicity. It is important to note that the bioavailability of zinc formulations may differ significantly.
Zinc deficiency in older people contributes to susceptibility to infection and osteoporosis.[14][15] Zinc supplementation has been shown to reduce the risk of infection in some studies.[59][60]
With acrodermatitis enteropathica, lifelong supplementation may be provided.[61] Long-term zinc supplementation may be guided by serial serum zinc measurement to individualise dosage. Additionally, as zinc competes with copper absorption, copper levels should be assessed regularly and concurrent copper supplementation may occasionally be necessary. Cessation of therapy leads to recurrence of signs and symptoms. Because the skin manifestations of zinc deficiency are linked to enzyme impairment, topical treatments are generally ineffective.
Parenteral zinc is rarely necessary, except for patients with intestinal failure and/or on prolonged total parenteral nutrition.[62] In patients who require parenteral nutrition, the dose of elemental zinc depends on clinical factors; higher doses are recommended in patients with GI losses or burns.[61]
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