Zinc

• Growth and tissue repair. The body uses zinc to make proteins and renew cells, including in wound healing. A pill does not guarantee faster healing for every wound. [1] [2]
• Normal immunity. Enough zinc helps the immune system work; supplements probably do little to prevent colds, but may shorten one you already have. [1][3]
• Avoiding a shortage. Several everyday foods provide zinc. Confirmed deficiency calls for care matched to its cause. [1]

Meat, cheese, grains, bread, nuts and shellfish provide zinc. Those eating plant-based meals can use grains and nuts and assess their whole diet; no single food has to do it all. [1] [2]

For a very restricted diet or persistent symptoms, a dietitian or clinician can help. A source list alone does not diagnose deficiency. [1]

Voedingscentrum recommends 9 mg a day for adult men and 7 mg for adult women; it lists 9.1 mg during pregnancy and 9.9 mg while breastfeeding. Children have different amounts. Eating less on one day does not prove a shortage: this guideline is enough for most people. [1]

The UK NHS lists about 9.5 mg for men aged 19–64 and 7 mg for women. That UK figure is not a reason to take extra pills automatically in the Netherlands. A varied diet usually supplies enough zinc. [1][2]

Voedingscentrum describes zinc deficiency as rare in the Netherlands as far as is known. True deficiency can involve changes to skin or mucous membranes, altered smell or taste, reduced resistance to infection and impaired growth. These signs are not unique to zinc deficiency; many other conditions can affect skin or taste.[1]

If symptoms persist or a child is not growing as expected, ask a clinician to assess diet and other causes. Repeatedly trying bigger doses could delay another diagnosis. If nutritional deficiency is confirmed, dietary changes or treatment can be chosen according to its cause rather than a symptom checklist.[1]

Extra zinc may help with a diagnosed shortage or when diet cannot meet your needs. For an existing cold, a Cochrane review of eight studies involving 972 people found a possible shortening of about two days. Confidence in this result is low: products and amounts varied widely, including lozenges, tablets and syrup; this does not show that every product or amount works the same way. There was little or no benefit for preventing colds, and any effect on symptom severity remains unclear. Studied amounts are not a daily nutrition recommendation. [3]

Unpleasant but generally nonserious side effects, such as a bad taste or stomach upset, occurred more often during cold treatment. Long-term excess can reduce copper absorption. Discuss combined products or persistent symptoms with a clinician or pharmacist instead of increasing the amount yourself. [1][2][3]

Ordinary food is unlikely to supply excessive zinc, according to Voedingscentrum. Prolonged high-dose tablets can impair copper absorption and cause deficiency. The NHS lists possible anaemia and weakened bones. An indefinitely high-dose supplement is therefore not a harmless insurance policy.[1][2]

The Dutch/European adult upper limit is 25 mg zinc per day from total intake; children's limits are lower. Separately, the NHS says not to take more than 25 mg per day from supplements without medical advice. Those two figures have different definitions. Neither is a recommended daily dose.[1][2]

Do not use zinc nasal sprays or other zinc products in the nose: loss of smell may be permanent. [4]