Recommended Daily Zinc Dosage for Adults
The recommended daily dose of zinc for adults is 15 mg, which can be obtained through a complete multivitamin and mineral supplement containing at least the government recommended daily allowance for zinc. 1, 2
General Recommendations for Healthy Adults
- The adult human body contains 2-3g of zinc, with approximately 0.1% being replenished daily, forming the basis for dietary recommendations 2
- For healthy adults, 15 mg of zinc daily is considered the Recommended Dietary Allowance (RDA) 2, 3
- Zinc supplementation should be in the form of a complete multivitamin and mineral supplement containing at least the government recommended daily allowance 1
Zinc Formulations and Absorption
- Different zinc salts (sulfate, acetate, gluconate, citrate) are available, with similar efficacy but potentially different tolerability profiles 1
- Zinc citrate and zinc gluconate have comparable absorption rates (approximately 61%) when taken as supplements without food 4
- Zinc oxide is less well absorbed (approximately 50%) and may be minimally absorbed by some individuals 4
- Organic compounds such as zinc histidinate, zinc gluconate, and zinc orotate show better tolerability than inorganic zinc sulfate and zinc chloride 1
Special Populations and Conditions
- Following bariatric surgery procedures like Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), 15 mg zinc daily is recommended 1
- For malabsorptive procedures such as biliopancreatic diversion with duodenal switch (BPD/DS), at least 30 mg zinc daily is recommended 1
- For patients with Wilson's disease, higher doses of 150 mg elemental zinc daily (administered in three divided doses, 30 minutes before meals) are recommended 1
- For children under 50 kg with Wilson's disease, 75 mg elemental zinc daily is recommended 1
- In acquired zinc deficiency, 0.5-1 mg/kg per day of elemental zinc can be given orally for 3-4 months 1
Monitoring and Precautions
- Zinc toxicity can occur with extremely high intakes, causing symptoms like nausea, vomiting, epigastric pain, lethargy, and fatigue 3
- Intake of 100-300 mg zinc daily (well above the RDA) can induce copper deficiency with symptoms of anemia and neutropenia, as well as impaired immune function 3
- Even lower levels of zinc supplementation, closer to the RDA, may interfere with copper and iron utilization and adversely affect HDL cholesterol concentrations 3
- When giving additional zinc and copper supplements, maintain a ratio of 8-15 mg zinc to 1 mg copper 1
- Taking zinc with food interferes with its absorption, but this may be necessary if it ensures compliance 1
Treatment of Zinc Deficiency
- For mild zinc or copper deficiency, consider giving two Forceval daily and recheck levels after 3 months 1
- For severe zinc deficiency with normal or borderline copper levels, treat with high-dose zinc supplement for 3 months and recheck levels 1
- If both zinc and copper are low, consider prescribing two Forceval daily for 3 months and recheck levels 1
- Adequacy of treatment with zinc is judged by clinical and biochemical improvement and by measuring 24-hour urinary excretion of copper (for Wilson's disease) 1