Zinc: roles, daily requirements, and signs of deficiency
Zinc is present in our body in very small quantities, and yet it is involved almost everywhere. Immunity, skin, hair, nails, vision, fertility: this discreet mineral is a true Swiss Army knife.
At Pure Lab Nutrition, we want you to understand what you are taking. Here is the essential information to know about zinc: its roles, your daily needs, where to find it, situations at risk of deficiency, how to choose it wisely, and the mistakes to avoid.
📑 Table of Contents
- What is zinc used for?
- How much zinc per day?
- Where to find zinc in food?
- Who is at risk of a zinc deficiency?
- Zinc and copper: a balance to respect
- Choosing a zinc supplement wisely
- Common mistakes
- Myths and misconceptions: fact vs. fiction
- Frequently asked questions
- In summary
What is zinc used for?
Zinc is a trace element: our body needs it in small quantities, but it can neither produce it nor store large reserves of it. It must therefore be provided regularly through diet.
✅ Its officially recognized roles
At the European level, zinc has numerous authorized health claims. It contributes in particular:
- to the normal functioning of the immune system
- to the maintenance of normal skin
- to the maintenance of normal hair and nails
- to the maintenance of normal vision
- to normal fertility and reproduction
- to the protection of cells against oxidative stress
- to normal cognitive function
- to the normal metabolism of macronutrients (carbohydrates, fats, proteins)
🔧 How does it work? The essentials in simple terms
Zinc functions a bit like an essential spare part. It is a component of a very large number of enzymes, those proteins that accelerate the body's chemical reactions, and it helps other proteins maintain their shape. This explains why it is found in immunity, skin renewal, protein synthesis, and cell protection.
Since the body does not have true mobilizable reserves, regular intake matters more than large, one-off intakes. This is also why it is better to aim for a sufficient daily diet rather than "shock treatments."
How much zinc per day?
Your needs depend on your diet. In France, ANSES sets nutritional references for zinc that vary according to the amount of phytates consumed, as these plant compounds inhibit its absorption.
| Phytate intake | Adult women | Adult men |
|---|---|---|
| Low (300 mg/day) | 7.5 mg/day | 9.4 mg/day |
| Medium (600 mg/day) | 9.3 mg/day | 11.7 mg/day |
| High (900 mg/day) | 11 mg/day | 14 mg/day |
These values correspond to the nutritional references for the population (RNP), that is to say, the intake that covers the needs of almost all healthy adults. Concretely, the richer your diet is in whole grains and legumes, the higher your zinc needs are. ANSES also sets a safe upper limit of 25 mg per day for adults, from all sources combined.
Where to find zinc in food?
🦪 Animal sources
Oysters are the champions, followed by red meat, organ meats, shellfish, cheese, and eggs. Zinc of animal origin is generally better absorbed.
🌱 Plant sources
It is also found in whole grains, legumes, seeds (pumpkin, sesame), and oilseeds. However, these foods contain phytates, which reduce zinc absorption.
🍽️ A typical zinc-rich day
- Breakfast: sourdough bread toast, an egg, a yogurt
- Lunch: salad of soaked and cooked lentils, pumpkin seeds, a piece of cheese
- Snack: a handful of cashews or almonds
- Dinner: red meat, shellfish, or, in a vegetarian version, a dish of chickpeas and quinoa
Varying sources, both animal and plant, remains the simplest way to cover your needs without thinking about it.
Tip: soaking, sprouting, and fermentation (sourdough bread, for example) reduce the phytate content.
Who is at risk of a zinc deficiency?
👥 Profiles to watch
- Vegetarians and vegans: fewer animal sources and more phytates. To learn more, read Vegan or vegetarian: supplements to consider
- Seniors: diet sometimes less varied and less efficient absorption
- Athletes: increased losses, especially through perspiration
- People whose diet is not very varied or highly processed
🔍 Warning signs
Insufficient intake can manifest in non-specific ways: recurring infections, slow healing, fragile skin, brittle nails, dull hair, decreased sense of taste. These signs have many other possible causes: only a healthcare professional can determine a deficiency, if necessary with a blood test.
📝 A concrete example
Let's imagine Léa, 29, vegetarian for two years, who eats a lot of whole-wheat bread, lentils, and chickpeas. Her diet is high in phytates: her zinc needs are therefore in the high end of the table. She can first act on her plate (sourdough bread, soaked legumes, pumpkin seeds), then, after talking to her doctor, consider a supplement at a reasonable dose.
🩺 When should you talk to your doctor?
Consult if several of these signs persist or add up, if you are following a very restrictive diet, if you have a digestive disease that hinders nutrient absorption, or if you are taking long-term treatment. Blood zinc testing has its limitations: its interpretation is the responsibility of a healthcare professional, who will cross-reference it with your diet and symptoms.
Zinc and copper: a balance to respect
Zinc and copper partially use the same absorption pathways in the intestine. When a lot of zinc is provided over a long period, the body absorbs less copper, another essential trace element. This is one of the reasons why ANSES set a safe upper limit of 25 mg of zinc per day for adults, from all sources combined.
In practice, this risk mainly concerns people who combine several products or take high doses for months without supervision. A nutritional dose, taken in compliance with the label, follows a completely different logic. Simply keep track of all your sources: multivitamins, beauty formulas, throat lozenges, and single zinc supplements.
Choosing a zinc supplement wisely
🧬 The form matters
Not all forms of zinc are absorbed the same way. A study published in 2014 in the Journal of Nutrition showed that zinc in the form of citrate or gluconate was better absorbed than zinc oxide. And a 2007 study observed superior bioavailability of bisglycinate compared to gluconate. We detail these results in our comparison of zinc forms.
📏 The dose
More is not better. Prolonged excess zinc can disrupt copper absorption. Respect the indicated dose and do not combine several supplements containing zinc without professional advice.
⏰ The timing
- Take your zinc away from tea, coffee, and dairy products, which can hinder its absorption
- Space it out by a few hours from a iron supplement
- If you have a sensitive stomach, take it during a meal
🛡️ Our zinc bisglycinate formulas
✅ Zinc Bisglycinate + vitamins B6 and C: 15 mg of zinc per day, long 1-year course
✅ Zinc Bisglycinate Instant+: 15 mg of zinc + vitamin B6, in pocket format for 30 days
✅ Vegan formulas, lactose and gluten-free
👉 Discover our Zinc Bisglycinate and our Zinc Bisglycinate Instant+.
Common mistakes
- Combining sources without counting: a multivitamin, a hair formula, and a zinc supplement can all contain zinc
- Taking it with morning coffee: it is better to space it out
- Self-diagnosing a deficiency based on brittle nails or dull hair
- Giving up too soon: skin, hair, and nails renew themselves slowly
Myths and misconceptions: fact vs. fiction
❌ "White spots on nails mean a zinc deficiency"
False, most of the time. These small spots are generally linked to minor bumps at the base of the nail. They are not enough to conclude a deficiency of anything. To learn more, read Brittle or ridged nails: causes and solutions.
❌ "The more you take, the better you defend yourself"
False. Zinc contributes to the normal functioning of the immune system, but beyond your needs, taking more provides no additional benefit and can unbalance copper intake.
✅ "Plant-based diets require more vigilance"
True. Phytates in whole grains and legumes inhibit zinc absorption, which explains higher needs. Soaking, sprouting, and fermentation help reduce them.
Frequently asked questions
❓ Can you take zinc every day?
Yes, at a reasonable dose and without exceeding the safe upper limit of 25 mg per day set by ANSES for adults, from all sources combined.
❓ Morning or evening?
The timing matters less than consistency. Choose a fixed time, away from tea, coffee, and any iron supplement.
❓ Zinc and vitamin C, a good combination?
Yes. Both contribute to the normal functioning of the immune system and the protection of cells against oxidative stress. To learn more, read Immunity: the nutrients that really count.
❓ Does a vegetarian necessarily have to take zinc?
No. A varied vegetarian diet that includes well-prepared legumes, seeds, oilseeds, eggs, and dairy products can cover needs. Supplementation should be discussed on a case-by-case basis, ideally with a healthcare professional.
❓ Can zinc be poorly tolerated?
Taken on an empty stomach, it can cause nausea in some people. Taking it during a meal often solves the problem. Chelated forms like bisglycinate are known to be well tolerated.
In summary
1️⃣ An essential trace element, to be provided every day
2️⃣ Needs that vary according to the richness of your diet in phytates
3️⃣ At-risk profiles: vegetarians, seniors, athletes
4️⃣ A well-absorbed form and a reasonable dose for intelligent supplementation
Pure Lab Nutrition ... The art of nourishing your well-being.
Sources:
- Regulation (EU) No 432/2012 establishing a list of permitted health claims. EUR-Lex
- ANSES (2021). Nutritional references for vitamins and minerals. anses.fr
- Wegmüller R. et al. (2014). Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide. The Journal of Nutrition, 144(2), 132-136. folia.unifr.ch
- Gandia P. et al. (2007). A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers. International Journal for Vitamin and Nutrition Research, 77(4), 243-248. PubMed
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