A customer came in recently after her third cold of the winter and asked me what was wrong with her immune system. We got talking about her diet, and it turned out she'd gone mostly plant-based a year earlier, trained four times a week, and hadn't given a second's thought to minerals. I couldn't diagnose anything from behind a shop counter, and I told her so. But zinc deficiency in the UK is a lot more common than people think, and her situation ticked most of the risk boxes. Zinc is the quiet workhorse of the mineral world: involved in hundreds of enzyme reactions, needed constantly, stored barely at all, and missing from a surprising number of British diets.
Why zinc matters more than its press suggests
Zinc doesn't have the celebrity status of vitamin D or magnesium, but look at what it's actually credited with under the official register of health claims. Zinc contributes to the normal function of the immune system, to normal fertility and reproduction, to the maintenance of normal testosterone levels in the blood, to the maintenance of normal skin, hair and nails, to normal cognitive function, and to the protection of cells from oxidative stress. That's not marketing, that's the authorised claims list. Very few nutrients touch that many systems.
The catch is that your body has no meaningful zinc store. You need a steady supply from food, and if the supply drops, function quietly drops with it.
Possible signs of zinc deficiency
Let me be straight about this bit: none of these signs is proof of anything on its own, and if something is persistently wrong you should see your GP, who can test properly rather than guess. That said, the pattern I've learned to ask about over 30 years looks like this:
- Picking up every cold and bug going, and taking longer than everyone else to shake them off
- Cuts and scrapes that seem slow to heal
- A dulled sense of taste or smell
- Skin playing up: spots, dryness, irritation that appeared alongside a diet change
- Brittle nails, sometimes with white marks, and lacklustre hair
- In men, flagging libido alongside low energy
One of those alone means little. Several together, plus a risk factor from the next section, is worth a proper look.
Who's most at risk in the UK
Zinc from meat and shellfish is well absorbed. Zinc from plants is not, because compounds called phytates in grains, pulses and seeds bind it in the gut. That single fact explains most of the risk list:
- Vegans and vegetarians, who eat less zinc and absorb less of what they eat
- People who train hard, since zinc is lost through sweat
- Older adults, who tend to eat less of it and absorb it less efficiently
- Anyone under sustained stress or drinking heavily
- People on very restricted or low-calorie diets
How much zinc do you need?
The UK reference intake is 9.5mg a day for men and 7mg for women, and the safe upper level for long-term supplementation is generally put at 25mg a day. That's an important number, because with zinc, more is emphatically not better. Taking large doses for months can interfere with copper absorption and cause its own problems. A supplement in the 10-20mg range, taken with food, covers the gap for almost everyone without going near the ceiling. And count what's in any multivitamin or fortified product you already take before adding more.
The best form of zinc supplement
Here's where I get opinionated, because this is where the industry cuts corners. The zinc in most cheap supplements is zinc oxide, and it's used for one reason: it's the cheapest form available. It's also one of the most poorly absorbed. You pay less and you absorb less, which is a false economy in a capsule.
Better forms are chelated or bound to organic acids: picolinate, citrate, bisglycinate. Zinc picolinate is the one I've recommended for years because it's consistently well absorbed and gentle on the stomach. Our own LSC Zinc Picolinate 20mg is exactly that: 20mg of well-absorbed zinc, one capsule a day with food, no fillers, £11.95 for a two-month supply. It sits within the safe range and does the job without theatrics. You'll find it alongside the rest of our minerals in the vitamins and minerals collection.
View in the shop
Food still comes first
As ever, the capsule is the backstop, not the plan. Oysters are the famous one, but beef, lamb, crab, prawns, eggs, cheese, and for plant-based eaters pumpkin seeds, hemp seeds, lentils and chickpeas all contribute. If you're plant-based, soaking and sprouting pulses reduces the phytates and improves what you absorb. A diet with some of these most days plus a modest supplement is a solid position for anyone in the risk groups.
FAQ
Q: How do I know for certain if I'm zinc deficient?
A: You don't, from symptoms alone. Blood testing for zinc is imperfect but it's far better than guessing, so speak to your GP, or use a proper venous blood testing service. Symptoms plus risk factors justify testing, not self-diagnosis.
Q: When should I take zinc, morning or night?
A: Whenever you'll remember it, with food. Zinc on an empty stomach makes some people nauseous. If you take iron or high-dose calcium, take the zinc at a different meal, as they compete for absorption.
Q: Can I just take a high dose when I feel a cold coming?
A: Short-term zinc lozenges at the first sign of a cold have some reasonable research behind them. But the better strategy is not being low in the first place. Zinc supports normal immune function every day, not just in a crisis.
Q: Is 20mg a day safe long term?
A: For most adults, yes, it sits under the generally accepted upper level of 25mg. Just make sure you're not doubling up across a multivitamin, fortified foods and a separate zinc product, and check with your GP if you're on medication.