Zinc function

  • Protein structure
    • Forms bonds between cysteine and histidine
    • Forms zinc finger transcription factors
  • Aids in maintenance and stability of the nuclear membrane
  • Essential part of many enzymes (> 100), including DNA polymerase, carbonic anhydrase, ACE, alkaline phosphatase, metallothionein, superoxide dismutase, and collagenases

Zinc deficiency

  • Causes
    • Inadequate dietary intake
    • Acrodermatitis enteropathica: congenital deficiency of the zinc/iron-regulated transporter-like protein (ZIP)
    • Malabsorption (e.g., due to Crohn disease), liver, and renal disease
    • Total parenteral nutrition (TPN)
    • Chronic liver disease (esp. liver cirrhosis)
    • Bowel resection
  • Clinical features
    • Impaired wound healing
      • Inability to replace type III collagen with type I collagen
    • Dysgeusia
      • On the upper surface of the tongue, there are taste receptor cells known as “taste buds”. These cells regenerate frequently but the activity reduces when zinc is deficient, which causes dysgeusia.
    • Anosmia
    • Immune dysfunction
    • Male hypogonadism
    • Dermatitis
      • Perioral (a) and perianal (b) erythema and pustules can be seen.Pasted image 20231013204734.png
    • Alopecia
    • In patients with liver cirrhosis: associated with accelerated progression of cirrhosis and aggravated clinical symptoms (e.g., hepatic encephalopathy)
    • Diarrhea
    • Impaired growth and development
  • Diagnosis: measurement of plasma zinc levels
  • Treatment: oral zinc supplementation