Zinc is one of the most important trace elements in the human body, yet one of the least understood. Involved in more than 300 enzymatic reactions, it plays a role in protein synthesis, immune regulation, skin health, cell growth, and fertility. Here's what you need to know about its benefits, the signs of a deficiency, and the best food sources.
What is zinc?
Zinc is an essential trace element—the body cannot synthesize it and must obtain it exclusively through diet. The human body contains 2 to 3 grams, concentrated mainly in the bones, muscles, liver, pancreas, prostate, eyes, and skin. The recommended daily intake (RDI) is 11 mg for an adult man and 8 mg for an adult woman, according to the EFSA.
Long underestimated, zinc is now recognized by numerous scientific studies as an essential nutrient, just like iron. Its bioavailability varies depending on the source: zinc from animal sources (meat, seafood) is better absorbed than that from cereals and legumes, whose phytates reduce intestinal absorption.
The health benefits of zinc
Skin, healing and acne
Zinc plays a central role in skin health. It regulates sebum production by the sebaceous glands, thus preventing the appearance of blackheads and pimples. It acts directly against Cutibacterium acnes , the bacteria responsible for acne, and reduces the associated inflammatory response. Clinical studies have shown that treatment with zinc (zinc gluconate or zinc sulfate) significantly reduces acne lesions, with efficacy comparable to some topical antibiotics. To learn more about natural acne treatments, our article "How to Get Rid of Acne" details the available approaches.
Zinc also plays a role in the synthesis of collagen, the skin's structural protein that gives it rigidity and elasticity. It accelerates healing by stimulating the proliferation and migration of keratinocytes. Its antioxidant action protects skin cells from oxidative stress induced by UV rays and pollution. To understand the mechanisms of skin aging, our article "Understanding the Skin" explains the structure and renewal of the epidermis.
Immune system
Zinc is a major regulator of immunity. It influences the development and activation of B lymphocytes (antibody-producing cells) and T lymphocytes (killer cells). Even a moderate zinc deficiency significantly weakens the immune system and increases susceptibility to viral and bacterial infections. Studies have shown that zinc supplementation reduces the duration and severity of common cold symptoms. Zinc also limits histamine release, which can help people with allergies. To learn more about ways to boost your immunity naturally, our article "How to Have Good Immunity" offers a comprehensive approach.
Hair and nails
Zinc is essential for the synthesis of keratin, the protein that makes up 95% of the hair fiber and nail plate. It strengthens the hair shaft in the bulb, cleanses the scalp, activates follicular microcirculation, and prevents hair loss related to deficiencies. A zinc deficiency often manifests as white spots on the nails (leukonychia), brittle nails, and reversible diffuse alopecia. To understand the link between zinc and hair loss, our article on how to prevent hair loss outlines the deficiencies to watch out for.
Other documented benefits
Zinc supports the normal development of children and the fetus during pregnancy. It participates in DNA synthesis and cell division. Its antioxidant properties protect against cellular aging and oxidative stress. It maintains normal cognitive function, plays a role in male reproductive functions (testosterone synthesis, sperm quality), and helps stabilize several hormones, including insulin and thymulin.
Signs of a zinc deficiency
Zinc deficiency is more common than you might think: according to the WHO, it affects approximately 17% of the world's population. Those most at risk include the elderly, vegetarians and vegans (phytates in legumes reduce absorption), pregnant and breastfeeding women, people with digestive diseases (Crohn's disease, malabsorption), and people under chronic stress or who regularly consume alcohol, tobacco, and coffee, which deplete zinc reserves.
Signs of a deficiency include unexplained fatigue, increased susceptibility to infections, slow wound healing, skin problems (acne, eczema), hair loss, brittle nails with white spots, taste and smell disturbances, and, in children, growth retardation. A blood test (plasma zinc level measurement) can confirm a deficiency.
Conversely, an excess of zinc (greater than 40 mg/day over a prolonged period) can induce a deficiency in copper, another essential trace element, because the two minerals compete for the same intestinal transporters.
What foods are rich in zinc?
The best dietary sources of zinc are oysters (the most concentrated source: up to 22 mg/100g), red and white meats, organ meats (such as calf's liver), eggs, pumpkin seeds (7.5 mg/100g), wheat germ, cashews, and legumes (lentils, chickpeas). Whole grains contain zinc, but their phytate content reduces its absorption—soak legumes before cooking to minimize this effect.
To optimize the absorption of dietary zinc, consume it with vitamin B6 (poultry, salmon, banana, chickpeas) which promotes its assimilation, and with vitamins B2 and B3 which potentiate its action.
In cases of confirmed deficiency or increased needs, zinc supplementation (zinc gluconate, bisglycinate, or picolinate, the best-absorbed forms) may be considered. Adhere to the Recommended Daily Allowance (RDA) and do not exceed 25 mg/day without medical advice.
Frequently asked questions about zinc
What is the difference between the different forms of zinc in dietary supplements?
Zinc is available in several forms in supplements: sulfate (good bioavailability, may irritate the digestive system), gluconate (well tolerated, average bioavailability), bisglycinate, and picolinate (the best absorbed and tolerated, recommended for people with sensitive stomachs). Formulas combining zinc and copper (in a 10:1 ratio) prevent an imbalance between these two minerals during long-term supplementation.
Is zinc effective against acne?
Yes, clinical evidence supports this. Several meta-analyses have confirmed the effectiveness of oral zinc (zinc sulfate or gluconate, 30 to 45 mg/day of elemental zinc equivalent) in reducing inflammatory acne lesions. While its effectiveness is lower than that of oral antibiotics, zinc has a significantly better safety profile for long-term use.
Does zinc really help fight colds?
Yes, provided it is taken at the first sign of symptoms. A Cochrane meta-analysis (2015, updated 2021) showed that zinc (in the form of tablets or syrup, 75 mg/day of zinc equivalent) taken within 24 hours of the onset of symptoms reduces the duration of a cold by approximately 33%. Its preventive effect is less well established.