Zinc: what it does, deficiency symptoms and zinc-rich foods

What zinc does

Zinc is a trace element — a mineral the body needs in small but essential amounts — with a huge influence, because it acts as a cofactor for hundreds of enzymes spread throughout the body. This means zinc does not do a single thing, but is a piece without which many processes do not work well. The most relevant: the immune system depends on zinc to produce and activate its defence cells, so its deficiency weakens defences and raises infections. Wound healing and skin renewal need zinc, which is why its lack shows up in slow wounds and skin problems. Taste and smell depend on it. And it also takes part in DNA and protein synthesis — crucial in the growth of children and teenagers — and in fertility. A discreet mineral with a huge CV.

The symptoms of deficiency

Because zinc is involved in so many processes, its deficiency shows up on several fronts at once, and none is exclusive, which is why it is hard to recognise:

• More infections than usual: frequent colds, wounds that get infected.
• Wounds and cuts that are slow to heal.
• Skin problems: dermatitis, acne, dryness.
• Hair loss.
• Loss or alteration of taste and smell.
• Loss of appetite and, in children, growth delay.

Who is most at risk

Zinc deficiency, like that of other minerals, comes from eating little or absorbing it poorly. The highest-risk groups are vegans and vegetarians, not because plants lack zinc, but because the phytates that accompany them hinder its absorption; older people, who tend to eat less and absorb worse; those with digestive diseases that hamper absorption (coeliac disease, Crohn's, colitis); and people with alcoholism, who combine worse intake and worse absorption. Pregnancy and breastfeeding also raise needs. Recognising yourself in one of these groups does not mean you have a deficiency, but it does mean paying more attention to zinc sources in your diet.

Where zinc is (and how to absorb it better)

The star source, with no rival, is oysters: they are the richest food in zinc there is, by far. After them come other shellfish, red meat and poultry, all with well-absorbed zinc. Among plant sources are legumes, nuts, seeds — especially pumpkin — and wholegrains. The key nuance, as with iron, is absorption: plant zinc comes with phytates that hinder it, so those who eat no shellfish or meat need not only more but to apply tricks that reduce phytates: soaking legumes, choosing sourdough bread (fermentation reduces phytates), and sprouting seeds and legumes. With these adjustments, a plant-based diet covers zinc without difficulty in most cases.

Zinc and colds: separating the myth

Every autumn zinc lozenges reappear as a supposed cold remedy, so it is worth putting the evidence in its place. What the reviews show: zinc lozenges, taken in the first 24 hours of a cold, MAY slightly shorten its duration, perhaps by around a day. But you have to read the fine print: the effect is modest, varies a lot across studies depending on the form and dose of zinc, and only applies if taken very early. It does not prevent colds, it is not an antiviral, and taking it all year makes no sense. Also, lozenges can cause a bad taste or nausea, and prolonged high-dose use interferes with copper. The honest conclusion: it may help a little if you catch it in time, but it is neither miraculous nor to be overdone.

When (and how much) to supplement

For most people, a varied diet covers zinc without pills. Supplementation makes sense in specific cases: confirmed deficiency, certain digestive diseases, or stages of high needs under professional guidance. But here is a particularly important warning that sets zinc apart from other minerals: its sustained excess is not harmless. Zinc and copper compete for absorption, so taking high doses of zinc long-term can cause a copper deficiency, with its own problems such as anaemia or neurological changes. That is why, more than any other, the zinc rule is not to overdo it: cover your needs, do not multiply them. If you decide to supplement, reasonable doses and better with the judgement of a professional who assesses your full case.

Zinc is another example of why knowing your real diet is worth more than chasing supplements, and there Renzy makes it easy without keeping counts by hand. By photographing your meals you see at a glance how often shellfish, meat, legumes, nuts or seeds enter your week, and you spot whether your pattern leaves you short on zinc without realising — especially if you eat little animal source. With that clear data you can adjust just what is needed, add the missing sources and apply the absorption tricks, instead of reaching for pills you may not need. Because with zinc, as with almost all micronutrients, well-chosen food beats the pot of capsules.