Zinc

Essential trace mineral for immunity, wound healing, and sensory function

Immune Function Wound Healing Taste & Smell Antioxidant

Evidence strength:

Moderate (immune, wound healing); evidence in deficient populations is strong

Overview

Zinc is an essential trace mineral involved in over 300 enzymatic reactions. It plays a central role in immune cell development, wound healing, protein synthesis, DNA synthesis, and the senses of taste and smell. Zinc cannot be stored in the body, so regular dietary intake is essential.

Rich food sources include red meat, shellfish (particularly oysters), poultry, beans, nuts, and whole grains. Absorption from plant sources is reduced by phytates, which makes vegetarians and older adults at higher risk of marginal deficiency.

Key fact for seniors Zinc deficiency is estimated to affect 30–40% of older adults. Age-related decline in zinc status contributes to immunosenescence (the age-related decline in immune function), impaired wound healing, and the loss of taste and smell common in older age.

What the Evidence Shows

Immune function and infection

Zinc is essential for the development and function of T-cells, natural killer cells, and neutrophils. Supplementation in deficient older adults improves multiple markers of immune function. Meta-analyses show that zinc lozenges (≥75 mg/day of elemental zinc) reduce the duration of the common cold by approximately 1–2 days when started within 24 hours of symptom onset.

Wound healing

Zinc is required for collagen synthesis and cell proliferation. Deficiency impairs wound healing, and supplementation in those who are deficient accelerates recovery. Zinc sulphate supplements are used clinically for leg ulcers and pressure sores in nutritionally depleted patients.

Age-related macular degeneration (AMD)

The AREDS trial established that high-dose zinc (80 mg elemental zinc) combined with antioxidant vitamins reduces progression to advanced AMD in those with intermediate disease. This is one of the most evidence-based uses of zinc supplementation.

Taste and smell

Zinc is essential for the renewal of taste receptor cells. Zinc deficiency is a recognised cause of hypogeusia (reduced taste) and hyposmia (reduced smell). Supplementation in deficient individuals can partially restore these senses.

Dosage by Age Group

Group	Recommended Daily Intake	Notes
Men 19+	11 mg/day	Elemental zinc
Women 19+	8 mg/day	Elemental zinc
Seniors — maintenance	8–11 mg/day	Dietary intake often falls short; a low-dose multivitamin may suffice
AMD prevention (AREDS formula)	80 mg/day	Only under medical guidance; requires copper co-supplementation
Tolerable upper limit	40 mg/day	Exceeding this chronically causes copper deficiency and anaemia

Australian brands

What to buy

Zinc supplements are most commonly available as tablets or capsules. Look for zinc picolinate, zinc citrate, or zinc gluconate on the label — these are better absorbed than zinc oxide. Standard-dose products (8–15 mg elemental zinc) suit most seniors for daily maintenance; higher-dose products should only be used under medical guidance.

Brand	Form	Typical product	Approx. cost
Blackmores	Tablet	Zinc Superkid (equivalent zinc for adults available; also in multivitamins)	$10–15
Bioglan	Tablet	Zinc 25 mg (120 tabs, zinc gluconate)	$12–16
Herbs of Gold	Capsule	Zinc Forte 30 mg (60 caps, zinc picolinate)	$18–24
Ethical Nutrients	Tablet	Zinc Fix (citrate + amino acid chelate, 30 mg, 60 tabs)	$18–24
Nature's Own	Tablet	Zinc 25 mg (100 tabs)	$10–14

Prices are approximate retail (Chemist Warehouse, Priceline, health food stores). For seniors taking zinc for immune support or general wellbeing, a 25–30 mg tablet every other day is a common approach. Herbs of Gold and Ethical Nutrients are well-regarded in Australian health food and pharmacy settings for higher-quality chelated forms.

Safety & Cautions

Important caution Long-term high-dose zinc (above 40 mg/day) competitively inhibits copper absorption and can cause copper-deficiency anaemia and neurological problems. Anyone taking therapeutic doses of zinc should also take a copper supplement (1–2 mg/day). Nausea is common when taking zinc on an empty stomach; take with food.

Drug interactions Zinc reduces absorption of fluoroquinolone and tetracycline antibiotics, as well as bisphosphonates — take at least 2 hours apart. Zinc may interfere with iron absorption when taken simultaneously; separate by 2 hours. ACE inhibitors and thiazide diuretics may increase urinary zinc loss.

Synergistic Combinations

Zinc + Vitamin D: Both support immune function through different but complementary mechanisms. Combined supplementation may be more effective for immune health in deficient older adults than either alone.
Zinc + Copper (2:1 ratio approximately): Always pair high-dose zinc with copper to prevent copper deficiency. This is not optional at doses above 25 mg/day.
Zinc + Antioxidants (AREDS formula): In AMD, zinc is used alongside vitamins C, E, and beta-carotene (or lutein/zeaxanthin) for maximum retinal protection.

📚 Key Scientific References

1.Gammoh NZ & Rink L. Zinc in Infection and Inflammation. Nutrients. 2017;9(6):624, PMID 28629136

Comprehensive review of zinc's essential roles in immune cell development, T-cell function, and the anti-inflammatory response, with particular relevance to older adults.
2.Wessels I et al. Zinc supplementation and immune factors in adults: a systematic review and meta-analysis of randomized clinical trials. Am J Clin Nutr. 2021;113(4):1048–1057, PMID 33356467

Meta-analysis of 35 RCTs: zinc supplementation significantly reduced circulating CRP and improved immune markers in adults.
3.Rostan EF et al. Evidence supporting zinc as an important antioxidant for skin. Int J Dermatol. 2002 — and updated review: Gupta M et al. Zinc Therapy in Dermatology: A Review. Dermatol Res Pract. 2014;2014:709152, PMID 25120566

Review confirming zinc's role in wound healing via collagen synthesis, cell proliferation, and membrane repair — with clinical evidence for leg ulcer treatment.
4.Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001;119(10):1417–1436, PMID 11594942

Landmark RCT establishing that zinc (80 mg) combined with antioxidants reduces progression to advanced AMD by 25% in high-risk individuals.
5.Maywald M & Rink L. Zinc deficiency as possible link between immunosenescence and age-related diseases. Immun Ageing. 2025;22(1):12, PMID 40390089

Recent review describing how age-related zinc decline contributes to immunosenescence, increased infection susceptibility, and chronic inflammation in older adults.