Zinc

What it is

Zinc is an essential trace mineral that the body cannot make and takes in from food or supplements. It acts as a cofactor for hundreds of enzymes involved in DNA synthesis, wound healing, skin turnover and the maturation of immune cells. Supplements are used mainly to correct or prevent deficiency, and are also taken for immune support and for skin.

Used for

• Deficiency
• Immune support
• Skin

What to know while taking it

Zinc is taken with food, largely because it irritates an empty stomach and can cause nausea. It competes for absorption with iron, so ferrous sulfate and zinc taken together leave less of each absorbed, and it binds tetracycline and fluoroquinolone antibiotics such as doxycycline and ciprofloxacin into complexes that pass through unabsorbed, so those are separated in time from the zinc. The main reason not to keep a high intake going indefinitely is copper: zinc and copper share an absorption pathway, and sustained high zinc quietly drives copper down, which in turn affects red blood cell production.

When to see a doctor

Persistent nausea or stomach pain that does not settle when the supplement is taken with food, or new fatigue, pallor or numbness and tingling after months of high intake, are reasons to see a doctor rather than adjust things by guesswork. Anyone on doxycycline, ciprofloxacin or prescribed iron should ask a doctor or pharmacist how to space the doses.

Worth knowing

• Long high doses deplete copper
• Nausea on an empty stomach