Zinc

Fundamental for immune function, DNA repair, and wound healing — and rapidly depleted during treatment.

What it is

Zinc is an essential mineral involved in over 300 enzymatic reactions governing immune response, DNA synthesis, protein production, taste and smell perception, and cell division. It is commonly and rapidly depleted during chemotherapy, poor appetite, and systemic illness.

Why it matters

Zinc is essential for NK cell function, T-cell maturation, and inflammatory regulation. Deficiency causes loss of taste and smell (extremely common during chemotherapy), impaired wound healing, and reduced immune response. Multiple clinical trials show zinc supplementation reduces oral mucositis severity during radiotherapy and accelerates recovery.

The evidence

Randomised trials confirm zinc supplementation reduces duration and severity of immune challenges and oral mucositis during head and neck radiotherapy. In cancer patients, zinc deficiency is associated with worse treatment tolerance and increased infection risk. A 2023 meta-analysis confirmed zinc's significant effect on post-chemo immune recovery.

This information is for educational purposes and does not constitute medical advice. Always discuss supplement use with your care team, particularly if you are undergoing active cancer treatment.

Dosing

15–30mg elemental zinc daily. Zinc bisglycinate or picolinate have the best absorption and fewest GI side effects. Take with food to reduce nausea. Separate from calcium and iron supplements by at least 2 hours.

Cautions

Long-term high-dose zinc (>50mg/day) depletes copper — add 1–2mg copper supplement if using zinc >30mg/day for more than a few months. Avoid zinc oxide (poorly absorbed). Space from iron, calcium, and tetracycline antibiotics.