From the Guidelines
Taking 250 mg of zinc at one time is potentially dangerous and not recommended. This dose far exceeds the recommended daily allowance of zinc, which is only 8-11 mg for adults 1. According to the most recent evidence, symptoms of zinc toxicity appear when ingestion exceeds 1e2 g of zinc, although this is much higher than the 250 mg dose in question, the dose is still high enough to cause adverse effects 1. Taking such a high dose can cause acute zinc toxicity with symptoms including severe nausea, vomiting, stomach cramps, diarrhea, and headaches. Within hours of ingestion, you may experience a metallic taste in your mouth and digestive distress.
Key Points to Consider
- Continued high-dose zinc supplementation can lead to copper deficiency, impaired immune function, reduced HDL ("good") cholesterol levels, and potentially permanent nerve damage 1.
- The tolerable upper intake level for zinc is only 40 mg per day for adults, and taking 250 mg at once exceeds this limit 1.
- If you're considering zinc supplementation, start with a much lower dose (typically 15-30 mg daily) and always consult with a healthcare provider first to determine if supplementation is necessary and appropriate for your specific health needs.
- Oral zinc has been associated with headaches, nausea, vomiting, decreased appetite, diarrhea, and abdominal cramps, and in high doses with prolonged use, can have more severe adverse effects such as low copper, anemia, leukopenia, neutropenia, and gastrointestinal ulcers 1. If you've taken this amount, you should contact poison control or seek medical attention immediately.
From the FDA Drug Label
Overdosage 4. 9 Overdose Single intravenous doses of 1 to 2 mg zinc/kg body weight have been given to adult leukemic patients without toxic manifestations. However, acute toxicity was reported in an adult when 10 mg zinc was infused over a period of one hour on each of four consecutive days. Profuse sweating, decreased level of consciousness, blurred vision, tachycardia (140/min), and marked hypothermia (94. 2° F) on the fourth day were accompanied by a serum zinc concentration of 207 mcg/dl. Symptoms abated within three hours. Hyperamylasemia may be a sign of impending zinc overdosage; patients receiving an inadvertent overdose (25 mg zinc/liter of TPN solution, equivalent to 50 to 70 mg zinc/day) developed hyperamylasemia (557 to 1850 Klein units; normal: 130 to 310) Death resulted from an overdosage in which 1683 mg zinc was delivered intravenously over the course of 60 hours to a 72 year old patient. Symptoms of zinc toxicity included hypotension (80/40 mm Hg), pulmonary edema, diarrhea, vomiting, jaundice, and oliguria, with a serum zinc level of 4184 mcg/dl. Calcium supplements may confer a protective effect against zinc toxicity
The effects of taking 250 mg of zinc at one time are not directly stated in the provided drug labels. However, based on the information provided, it can be inferred that taking a high dose of zinc, such as 250 mg, may lead to zinc toxicity. The symptoms of zinc toxicity include:
- Profuse sweating
- Decreased level of consciousness
- Blurred vision
- Tachycardia
- Hypothermia
- Hyperamylasemia
- Hypotension
- Pulmonary edema
- Diarrhea
- Vomiting
- Jaundice
- Oliguria
It is recommended to exercise caution when taking zinc supplements and to follow the recommended daily intake to avoid the risk of zinc toxicity 2.
From the Research
Effects of Taking 250 mg of Zinc at One Time
- The recommended daily intake of zinc is between 6.7 to 15 mg per day, according to the World Health Organization (WHO) 3.
- The European Food Safety Authority (EFSA) defines the tolerable upper intake level (UL) as 25 mg per day, whereas the Food and Drug Administration (FDA) allows 40 mg per day 3.
- Taking 250 mg of zinc at one time exceeds the recommended daily intake and may result in symptoms such as anemia, neutropenia, and zinc-induced copper deficiency 3.
- High intakes of zinc relative to copper can cause copper deficiency, and an excess of the recommended daily intake may lead to harmful effects 4.
- Zinc poisoning has been reported from many parts of the world, and long-term exposure to zinc compounds can lead to toxic effects on body systems, especially digestive, respiratory, and nerve systems, and also causes cancer 5.
- Patients with zinc toxicity may need chelating agents, other pharmacological treatment, protective lung ventilation, extracorporeal membrane oxygenation (ECMO), and supportive care 5.
- The current assumed range between safe and unsafe intakes of zinc is relatively narrow, and assessment of zinc nutriture is complex, involving a number of chemical and functional measurements that have limitations in sensitivity and specificity 4.
- A daily 5 mg increment of zinc would lower the risk of colorectal and esophageal cancer, whereas a large dose of zinc supplementation (daily 100 mg) showed no benefit in reducing prostate cancer risk 6.
- However, taking 250 mg of zinc at one time is considered a pharmacological dose, which may have different effects on human health compared to dietary doses 7.