💊 Nutrition
Zinc Deficiency — Symptoms, Causes & Best Food Sources (2026)
Zinc deficiency affects 2 billion people globally. Learn to recognise the symptoms, discover the best food sources, and understand supplement dosing. Updated January 2026.
Key Takeaways
- Zinc is involved in over 300 enzyme reactions including immune function and wound healing
- Oysters contain more zinc than any food — 74mg per 100g
- Plant zinc is less bioavailable — vegetarians need 50% more dietary zinc
- Deficiency causes hair loss, slow wound healing, loss of taste/smell, immune suppression
- Upper safe limit: 40mg/day from supplements — excess depletes copper
In This Article
What Zinc Does
Zinc is a cofactor for over 300 enzymes, essential for immune function, wound healing, DNA synthesis, taste and smell, and testosterone production.
2B+
People worldwide zinc deficient
300+
Enzymes need zinc
8–11mg
Daily requirement (8mg women, 11mg men)
Symptoms of Deficiency
- Impaired wound healing — cuts and sores heal slowly
- Frequent infections — reduced T-cell immune function
- Hair loss — diffuse thinning similar to iron deficiency
- Loss of taste and smell — classic zinc deficiency signs
- Acne and skin problems — zinc regulates sebum production
- Low testosterone and reduced fertility in men
| Food | Zinc /100g | Bioavailability |
|---|---|---|
| Oysters (raw) | 74mg | High |
| Beef (lean) | 5mg | High |
| Pumpkin seeds | 7.8mg | Moderate |
| Cashews | 5.6mg | Moderate |
| Lentils (cooked) | 1.3mg | Low (phytates) |
✅ Boost Plant Zinc Absorption
Soak beans and grains before cooking (reduces phytates 30–50%). Fermentation and sprouting also help. Pair plant zinc with vitamin C or animal protein for better absorption.🔢 Free Tool
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Open Free Calculator →Frequently Asked Questions
Does zinc help with colds?▼
Yes — zinc lozenges started within 24 hours of onset reduce cold duration by 33%. Only effective as lozenges near nasal passages, not standard tablets.
How to know if zinc deficient?▼
Serum zinc blood tests are unreliable. Clinical assessment (symptoms + diet history) is better. A 4–6 week therapeutic trial is often diagnostic.
Can you overdose on zinc?▼
From food — essentially impossible. From supplements above 40mg/day, copper deficiency can develop causing anaemia. Start at 15–25mg/day and increase if needed.
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⚕️ Medical Disclaimer: For informational purposes only. Not a substitute for professional medical advice. Always consult a qualified healthcare professional.
EC
Dr. Emma Clarke, PhD, RD
WellCalc Medical Contributor
All WellCalc articles are reviewed by qualified healthcare professionals following NHS, AHA, and WHO guidelines.