Zinc is an essential mineral that plays many important roles in the body. Getting enough zinc in your diet is important for maintaining proper immune function, fertility, growth and development, wound healing, and a myriad of other functions. However, consuming too much zinc can also be problematic.
The recommended dietary allowance (RDA) for zinc is 11mg per day for adult men and 8mg per day for adult women. Many experts consider 50mg of supplemental zinc to be excessive and potentially harmful if taken daily over an extended period of time.
Potential Benefits of Zinc Supplements
There are some situations where taking a zinc supplement providing up to 50mg per day may be appropriate for limited periods of time. Potential benefits include:
- Treating zinc deficiency – Taking high doses of zinc for 1-2 months can help restore normal zinc levels in those diagnosed with a deficiency.
- Wound healing – Applying zinc supplements topically and taking high doses (up to 50mg/day) for up to 3 months can improve wound healing in some people.
- Acne – Taking zinc supplements providing 30-45mg of elemental zinc per day may help improve severe acne, but only for up to 3 months.
- Age-related macular degeneration – Taking zinc supplements providing 80mg of elemental zinc (along with 2mg copper) may help slow vision loss from macular degeneration, but only under a doctor’s supervision.
- Immune health – Taking zinc lozenges providing up to 50mg/day zinc at the first signs of a cold may help shorten the length or reduce the severity of some upper respiratory infections.
In each of these situations, the high zinc dose is only intended for a limited time before transitioning back to the standard dose near the RDA.
Potential Risks of Too Much Zinc
Taking in 50mg or more of supplemental zinc daily over months or years can potentially lead to numerous health problems. Potential risks include:
- Copper deficiency – High zinc intake can interfere with copper absorption, leading to copper deficiency over time. This may cause anemia and neurological problems if left untreated.
- Suppressed immune function – Too much zinc can reduce the activity of immune cells and lower immunity.
- Stomach irritation – Zinc can cause nausea, abdominal cramps, and intestinal bleeding in high amounts.
- Kidney problems – Excess zinc may reduce kidney function and cause kidney stones.
- Neurological effects – Very high zinc intake over 150mg/day can lead to neurological problems like lethargy, dizziness, and numbness in extremities.
- Disrupted absorption of other nutrients – Too much zinc can interfere with the absorption of iron, folate, magnesium, and calcium.
Tolerable Upper Intake Level for Zinc
The Tolerable Upper Intake Level (UL) for zinc is the maximum amount that is likely to pose no risk of adverse health effects for most healthy adults when consumed daily over a lifetime. The UL for zinc is:
- 40 mg/day for adults age 19+
- 34 mg/day for adults age 18 and younger
- 23 mg/day for infants ages 0-6 months
- 12 mg/day for infants ages 7-12 months
Consuming 50mg of zinc per day from supplements exceeds the UL for all adults and would be expected to increase the risk of negative zinc side effects over months or years.
Upper Limit for Short-Term Zinc Use
Taking 50mg zinc daily from supplements could be safe when done in short durations of 1-3 months at a time, as long as you don’t exceed the total UL over the course of a full year. For example, taking 50mg/day for one month would equal 1,500mg total. As long as your total intake stays under 14,600mg/year (based on the adult UL of 40mg/day), short-term use at 50mg/day is less likely to cause problems.
Who May Need More than the UL for Zinc
There are a few scenarios where zinc intake higher than standard UL may be necessary and appropriate under medical supervision:
- Severe zinc deficiency – Doses up to 75-125mg/day may be used for 1-3 months to restore normal zinc status.
- Age-related macular degeneration – Under a doctor’s care, up to 80mg zinc with 2mg copper daily may be used to help slow vision loss.
- Recurring infections – With frequent infections, doses up to 50mg/day for 1-3 months may help restore immune function.
- Critical illness – Higher doses up to 75mg/day have been used in a hospital setting to help reduce risk of complications and death.
- Pregnancy – Pregnant women have slightly higher zinc needs, so doses up to 50mg/day may occasionally be used short-term under medical supervision.
In each of these medical situations, zinc intake would ideally be brought back down to standard doses near the RDA after the high-dose supplementation period ends.
Signs that Your Zinc Intake is Too High
Watch for the following signs that might indicate you are getting more zinc than your body can properly process:
- Nausea, vomiting, diarrhea
- Loss of appetite
- Abdominal cramps
- Headaches
- Trouble sleeping
- Anemia
- Neurologic problems like dizziness or tingling extremities
- Copper deficiency symptoms like neuropathy or anemia
- Lowered immunity with frequent illnesses
If you experience any of these symptoms while supplementing with zinc, stop taking the zinc and see your healthcare provider.
Forms of Supplemental Zinc
The two main forms of zinc in supplements are zinc gluconate and zinc picolinate.
Zinc gluconate is one of the most common and inexpensive supplemental forms of zinc. It contains 14% elemental zinc. 50mg zinc gluconate provides approximately 7mg elemental zinc.
Zinc picolinate contains 20% elemental zinc, so 50mg of this form provides 10mg elemental zinc. Some research shows zinc picolinate may have improved absorption compared to other forms like zinc gluconate.
Other less common forms include zinc acetate, zinc sulfate, zinc citrate, zinc orotate, zinc bound to amino acid chelates, etc. The percentage of elemental zinc varies but is typically in the range of 10-30%.
Table comparing different forms of supplemental zinc:
| Form of Zinc | Elemental Zinc % |
|---|---|
| Zinc gluconate | 14% |
| Zinc picolinate | 20% |
| Zinc acetate | 30% |
| Zinc sulfate | 23% |
| Zinc citrate | 16% |
| Zinc orotate | 8-15% |
| Zinc amino acid chelates | 10-15% |
When comparing amounts of different zinc supplements, be sure to pay attention to the amount of elemental zinc provided rather than just the total supplement weight.
Zinc Absorption Factors
Certain factors can enhance or inhibit zinc absorption in the body:
- Phytates from whole grains, beans, seeds, and nuts can bind zinc and reduce absorption.
- Iron supplements and calcium supplements can also impair zinc absorption when taken at the same time.
- Taking zinc with food improves absorption compared to taking on an empty stomach.
- Substances that increase stomach acid like lemon juice can improve zinc absorption.
- Zinc picolinate may have better absorption than other forms like zinc gluconate.
- Older adults absorb less zinc than younger people.
Zinc and Copper Balance
It’s important to maintain a proper zinc/copper ratio in the body. Taking in too much zinc can interfere with copper absorption over time leading to a copper deficiency.
For every 15-30 mg of supplemental zinc consumed daily, experts recommend taking 2 mg of copper to help prevent zinc from depleting copper status.
Without enough copper, high zinc intake can potentially lead to anemia, bone abnormalities, impaired immunity, heart problems, neuropathy, and other serious issues.
Safe Upper Limit for Long-Term Zinc Use
Sticking within the standard Tolerable Upper Intake Level (UL) for zinc is recommended for long-term daily use to reduce the risk of adverse effects. This means:
- 40 mg or less per day for adults 19+
- 34 mg or less for ages 18 or younger
Unless prescribed very high doses for a specific medical condition, most doctors recommend staying at or below the UL for zinc intake on an ongoing basis.
Conclusion
In most circumstances, taking 50mg of supplemental zinc daily would be considered too much for long-term use. The Tolerable Upper Intake Level for zinc is much lower at 40mg per day for adults and less for teens and children.
Consuming 50mg per day greatly exceeds the UL and may result in copper deficiency, impaired immunity, digestive issues, and other problems when done continuously over months or years. It’s generally recommended to stay at or below the standard UL for daily zinc intake unless instructed to take higher doses for a short time by a doctor.
However, taking 50mg of zinc from supplements or zinc lozenges could be safe for certain short-term uses like boosting immunity during illness or improving wound healing, as long as the total intake doesn’t consistently exceed the UL over a full year. It’s best to seek advice from a healthcare professional to determine if a daily 50mg zinc supplement is appropriate based on your specific situation and needs.
