How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Zinc
An essential trace element for immunity: a large part of the world's population is at risk of lacking it, but excess supplementation is toxic.
Benefits
- Added to an antidepressant, 25 mg per day reduced depression scores at 6 and 12 weeks, especially in treatment-resistant patients
- In healthy elderly people, 45 mg per day reduced infections
- In diabetics, lowers fasting blood glucose, postprandial blood glucose, and glycated hemoglobin (meta-analysis)
- In children in developing countries, reduces diarrhea, pneumonia, and related mortality (meta-analyses)
Precautions
Prolonged excess disrupts copper absorption. Do not exceed 25 mg per day long-term without medical advice.
Recommended dosage
25 to 45 mg per day in adult trials.
How to take it
- In adult trials: higher doses, 25 mg per day added to an antidepressant, 45 mg of zinc gluconate in elderly people.
- How long: in depressed adults, the effect of zinc added to treatment appears at 6 and 12 weeks.
- Not too much: a large share of the world's population is at risk of deficiency, but excess zinc supplementation is toxic.
- In children: 10 to 20 mg per day in trials conducted in developing countries, against diarrhea and respiratory infections.
Did you know?
An excessive intake of zinc relative to copper can lead to a copper deficiency.
What the studies say
This systematic review and meta-analysis concludes that zinc supplementation has beneficial effects on glycemic control in patients with diabetes. It shows a significant reduction in fasting blood glucose, postprandial blood glucose, and HbA1c. In addition, zinc supplementation also improved lipid parameters and blood pressure.
Jayawardena R, Ranasinghe P, Galappatthy P, Malkanthi R, Constantine G, Katulanda P. — Diabetology & metabolic syndrome (2012) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more