Description

• Nutritional condition whose manifestations may involve growth retardation; hypogonadism; cell-mediated immune dysfunction; poor wound healing; poor appetite; hair loss; depression; and increased incidence of infection, anorexia, diarrhea, and eye and skin lesions related to decreased zinc levels.
• System(s) affected: Endocrine/Metabolic; Nervous; Skin/Exocrine; Hematologic/Oncologic; Gastroenterologic

• Zinc deficiency may cause poor night vision, leading to falls; poor wound healing or chronic ulcer; or loss of smell and taste, which may cause worsening nutrition.
• Elderly persons living in institutions may have low zinc intake.

Pediatric Considerations
Zinc deficiency may cause failure to thrive and diarrhea, and may impair growth and development of secondary sexual characteristics.

Pregnancy Considerations
Requirements increase; deficiency may cause spontaneous abortion, inadequate weight gain

Epidemiology

• In the US: Rare in general population
• High prevalence in developing countries
• Predominate age: All ages
• Predominant sex: Male = Female

Risk Factors

• Drugs: Diuretics, penicillamine, sodium valproate, and ethambutol
• Low socioeconomic status
• Malabsorption syndromes
• Living in developing nations
• Hyperalimentation with zinc supplementation
• Thermal burns
• Strict vegetarian diet
• Alcoholism
• Chronic renal failure patients on hemodialysis

Genetics
Usually acquired, but rarely caused by acrodermatitis enteropathica (autosomal recessive) and associated with sickle cell anemia (autosomal recessive)

General Prevention

• Adequate diet
• Supplementation when indicated (see “Medication”)

Etiology

• Increased requirements:
  • Pregnancy
  • Lactation
  • Rapid growth phase in childhood
  • Burns
  • Major trauma
• Increased losses:
  • Diabetes
  • Cirrhosis
  • Renal disease
  • Malabsorption states (e.g., inflammatory bowel diseases)
  • Sickle cell anemia
  • Diuretics: Thiazides, chlorthalidone
• Decreased absorption:
  • Acrodermatitis enteropathica, an autosomal-recessive deficiency in the enzyme required for intestinal absorption
  • Geophagia
  • Chelating agents
  • Parasitism
  • Diet high in phytates (plant fiber)
  • Drugs: Penicillamines, tetracyclines, quinolones, bisphosphonates
• Insufficient dietary intake:
  • Vegetarianism
  • Parenteral hyperalimentation without zinc supplementation
  • Breastfeeding
  • Suboptimal zinc conditions in diet (rare)
  • Alcoholism

Commonly Associated Conditions

• Sickle cell anemia
• Malabsorption
• Parenteral hyperalimentation
• In the older patient: Those taking diuretics, those with diabetes mellitus, cirrhosis
• In hemodialysis patients, zinc deficiency is associated with depression.