Zinc !

Zinc is part of hundreds of enzymes and of the proteins that read DNA; it is key for growth, wound healing and fighting infection.

Updated 2026-11-01

Key facts

Cofactor of more than 300 enzymes: carbonic anhydrase, alcohol dehydrogenase, alkaline phosphatase, cytosolic superoxide dismutase (Cu/Zn), ALA dehydratase.
Forms the 'zinc fingers' of many transcription factors and nuclear receptors (steroid and thyroid hormones, vitamins A and D).
Deficiency: poor growth, dermatitis around body openings and on the limbs, alopecia, diarrhoea, impaired taste and smell, hypogonadism, infections.
Excess zinc induces metallothionein in the gut, which traps copper: it can cause copper deficiency (and is used in Wilson disease).

Sources: red meat, shellfish (oysters), poultry, legumes, seeds, whole grains. Phytates in cereals and legumes reduce its absorption.
Absorption: in the duodenum and jejunum through the ZIP4 transporter (SLC39A4 gene); it leaves the enterocyte through ZnT1. In blood it travels bound to albumin.
Roles: structural (zinc fingers, insulin stored as hexamers), catalytic (activates water in carbonic anhydrase) and regulatory (immune signalling, T-cell division).
Causes of deficiency: a diet low in meat and high in phytates, chronic diarrhoea, malabsorption (Crohn, coeliac disease), alcoholism, cirrhosis, kidney disease, zinc-free parenteral nutrition, acrodermatitis enteropathica (ZIP4 failure).
Excess: acute nausea and vomiting; chronically, copper deficiency with anaemia, neutropenia and myelopathy.
Lab: plasma zinc (falls with inflammation, low albumin and after meals: drawn fasting, in the morning); low alkaline phosphatase as an indirect clue.

In children with acute diarrhoea, WHO advises zinc together with oral rehydration salts: it shortens the episode.
Zinc deficiency is common in low- and middle-income countries, where it contributes to child stunting.
Zinc acetate is a maintenance treatment in Wilson disease because it blocks gut copper absorption.

Think of the answer, then tap the question to see it.

What are zinc fingers?

Protein domains in which a zinc atom holds a loop that binds DNA; many transcription factors and nuclear receptors have them.

Why can excess zinc cause copper deficiency?

Zinc induces metallothionein in enterocytes, which traps copper; it is lost when the cell is shed.

Which transporter fails in acrodermatitis enteropathica?

ZIP4 (SLC39A4 gene), which carries zinc from the gut lumen into the enterocyte.

Why is zinc given to children with acute diarrhoea?

It replaces losses, helps mucosal repair and immunity, and shortens the length and severity of the episode.

Educational information, not medical advice. For any symptom, see a health professional.

Sources: Zinc in diet: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); SLC39A4: Zinc transporter ZIP4 (human) (UniProt, 2026); Fact sheets - Malnutrition (World Health Organization, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.