Zinc

Studies in people

• Concern

  Immune system and copper levels³

  Too much zinc can block the body's absorption of copper and iron, and may affect the immune system.

• Open question

  Allergies and the immune system⁴

  Low zinc levels have been linked to allergies, and zinc supplements may ease allergic symptoms, but this is not yet certain.

• Open question

  Cold duration and side effects⁵

  In people with colds, zinc may shorten how long they last, but may cause more minor side effects.

• Open question

  Kidney disease risk⁶

  People who ate less zinc each day were more likely to develop kidney disease.

• Open question

  Childhood diarrhoea recovery⁷

  In children under 10 with diarrhoea, zinc helped more recover, but more children vomited.

• Benefit

  Fortifying staple foods⁸

  Zinc is lacking in many people's diets, and fortifying foods like rice and wheat may help.

• Open question

  How well the body absorbs it⁹

  Zinc glycinate and zinc gluconate seem to be absorbed better than other forms of zinc.

• Benefit

  Antiviral immune response¹¹

  In people on plant-based diets, zinc supplements restored a virus-fighting immune response that was low when zinc was lacking.

Study type not stated

• Concern

  Excess mineral harms digestion¹⁵

  Too much zinc can cause nausea, vomiting, stomach cramps and diarrhea, and block the body from absorbing iron and copper.

• Open question

  Immune system balance¹⁶

  Zinc helps immune cells work, but too much or too little zinc can both weaken your immune system.

• Benefit

  Immune system health¹⁷

  Zinc helps immune cells work and fight bacteria, parasites and viruses, and may help people who don't get enough.

• Benefit

  Immune and nerve health¹⁸

  Zinc helps the body grow and fight germs, and not getting enough may play a part in some diseases.

Single cases of misuse or overdose

One person or one incident, such as an accidental overdose or a mistake in a kitchen or factory. They are real, but a single case does not show what happens at normal amounts, so the signal does not count them.

• Blood cell health¹³

  A teen taking large daily zinc doses for acne got fatigue and low blood cells, which cleared up after he stopped.

How it’s made and used

• Infant nutrition and immunity¹⁰

  Babies need zinc from breast milk or food, and not getting enough can weaken their immune system.

• Kidney stones in teens¹²

  Teens who ate less zinc were more likely to get calcium kidney stones, though this link is not proof of cause.

• Daily mineral intake¹⁴

  Students got enough zinc from their meals, but their copper intake was lower than recommended.

• Nutrient loss in cooking¹⁹

  Cooking vegetables in brine lowers their zinc, and a newer freezing method keeps more zinc in.

• Immune cell function²⁰

  In lab and animal studies, zinc changed how immune cells called neutrophils release their traps and granules.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.