What is Zinc Toxicity?
Zinc is a type of metal that is usually found in nature and is necessary for the creation of numerous enzymes in the body. This makes it an essential mineral to our health. The amount of zinc we need each day varies depending on the person’s health, age and lifestyle. Generally, the recommended zinc levels in the blood are between 109 to 130 micrograms per liter.
Zinc plays a significant role in various bodily functions such as DNA expression (the process by which cells use DNA to make other vital components), stabilizing cell membranes, the metabolism of vitamin A, and the functions of taste and smell. These roles also make zinc very crucial during the growth and development of a fetus.
Interestingly, Zinc and copper levels in the body are inversely related, meaning when one increases, the other decreases. This makes zinc an important part of medication used to treat Wilson’s disease, a rare genetic disorder in which copper builds up in the body.
Despite the benefits, an excess of zinc, known as chronic zinc toxicity, could cause problems, primarily resulting in a deficiency of copper. Too much zinc can come from various sources such as inhaling it in certain work environments, consumption of too many dietary supplements, usage of zinc-containing denture cream, swallowing pennies due to an eating disorder called PICA, or receiving improperly prepared nutritional supplements administered through injections. Some unfortunate incidents of zinc toxicity have even resulted in fatalities. Therefore, it’s important to maintain a balanced level of zinc in the body.
What Causes Zinc Toxicity?
The suggested daily amount of zinc for an adult is 15 milligrams. Usually, you won’t see any symptoms unless you consume more than 1 to 2 grams of zinc. High levels of zinc can enter your body through your skin, by swallowing it, by breathing it in, or through a medical procedure.
If you inhale something like a smoke bomb, which contains zinc chloride, it can lead to chest pain, irritation in your airways, and may even resemble a severe lung condition known as Acute Respiratory Distress Syndrome (ARDS). In the long run, it may even cause scarring in the lungs.
On the other hand, breathing in zinc oxide, which can happen in occupations like welding or metalworking, may result in a condition referred to as “metal fume fever”. This condition usually accompanies flu-like symptoms, along with a cough and difficulty in breathing. This is presumed to occur due to zinc’s direct impact on the lining of the lungs.
It’s also possible to get too much zinc from dietary supplements, newer pennies (made after 1981, which contain zinc), solutions with more than 20% zinc chloride, or even from using too much denture cream, which could lead to a lack of copper in your body.
Lastly, excessive use of makeup, sunscreen, and ointments containing zinc oxide, can introduce high levels of zinc to your body through your skin.
Risk Factors and Frequency for Zinc Toxicity
The 2017 report from the American Association of Poison Control Centers saw 1236 incidents of people exposed to substances containing zinc. Unintentional exposure in kids under 5 made up a significant portion of these incidents (n = 535). Importantly, there were no reported fatalities or severe health problems.
Signs and Symptoms of Zinc Toxicity
Zinc toxicity can occur if a person consumes too much zinc. This often results in symptoms such as vomiting, spitting up blood, feeling sick, cramping muscles, loose watery bowel movements, and widespread tummy pain. These symptoms can be quite varied, making it a bit tricky to diagnose without suspecting zinc overdose first. Some groups, like kids or people with mental health conditions, might be more at risk if they swallow a large amount of zinc supplements or a foreign object containing zinc.
When suspected, it’s crucial to gather a complete diet, work, and lifestyle history because this could expose unseen sources of zinc. Inhaling zinc fumes can bring about flu-like symptoms, like cough, fever, body shivers, headache, feeling unwell, feeling sick, and muscular aches. Known as “metal fume fever” or “zinc shakes,” this can repeat over several days unless the person is not working. That’s why a comprehensive work history is crucial.
Long-term ingestion of zinc can result in a condition called “swayback,” which causes a slow-progressing nerve disease and anemia leading to increased tiredness, rigid muscles, unusual walking patterns, and insensitivity to body position. These symptoms are related to a lack of copper due to excessive zinc. Restoring a balanced zinc intake and adding copper supplementation can correct blood abnormalities within a few weeks. However, nerve issues can persist despite treatment.
Swallowing a large dose of zinc sulfate and concentrated zinc chloride primarily affects the gut, resulting in stomach pain, diarrhea, feeling sick, vomiting, and spitting up blood due to its harsh effects. Rarely, it might also hurt the kidneys.
- Vomiting
- Spitting up blood
- Feeling sick
- Cramping muscles
- Loose watery bowel movements
- Widespread tummy pain
- Flu-like symptoms from inhaling zinc
- Unusual walking patterns
- Increased tiredness
- Stomach pain
- Diarrhea and vomiting from ingesting zinc sulfate or zinc chloride
Testing for Zinc Toxicity
If you believe you have been exposed to harmful levels of zinc, it is critical to get in touch with a Poison Control Center or a medical expert who specializes in dealing with poisons as soon as possible. They can guide you on what to do next.
Doctors can investigate whether you might have zinc poisoning by checking the levels of zinc, copper, and a protein called ceruloplasmin in your body. These tests are usually the first step if zinc poisoning is suspected.
If you’ve accidentally eaten anything that contains a large amount of zinc, additional tests may be needed. These tests may include liver function assessments, a blood count to find out how many platelets (which help your body form clots to stop bleeding) you have, a check of creatinine and BUN levels to see how well your kidneys are working, and the level of a protein called pancreatic lipase, which helps break down fats in your body. Another couple of tests referred to as AST and ALT are specifically designed to evaluate liver function. A calculation known as PT or INR is done to figure out how long it takes for your blood to clot.
If there’s a chance you may have swallowed something solid made of zinc, your doctor might order an X-ray of your stomach. This test can help them look for any objects that show up on the X-ray because they block radiation. If you might have inhaled zinc, a chest X-ray might be useful, though it often doesn’t show any problems.
If the doctor suspects you have been exposed to high levels of zinc over a long period, the first step is again to check the levels of zinc, copper, and ceruloplasmin in the body. If these tests suggest that this might be the case, further investigations like studies of your bone marrow (the spongy tissue inside some of your bones that produces blood cells) may follow.
Treatment Options for Zinc Toxicity
If you accidentally swallow something that contains a lot of zinc, such as a penny, the main treatment is supportive care. This typically includes medication to control nausea (antiemetics), fluids to keep you hydrated, and specific drugs to reduce stomach acid production. These drugs, known as proton pump inhibitors (PPIs) or H2-blockers, are given not only to help with symptoms but also to prevent further release of zinc in your stomach by reducing the breakdown of the swallowed foreign body.
If an X-ray shows a large amount of foreign material in your stomach and intestines and you’re showing signs of toxicity, your healthcare provider might also consider a procedure known as whole bowel irrigation (WBI). This procedure is used to cleanse the bowel by introducing large amounts of fluids. In this case, it’s similar to treatments used for other harmful metals like iron, potassium, or lithium.
In extreme cases of swallowing a massive foreign body, surgical removal may be an option. Additionally, certain medicines—calcium disodium edetate (CaNa2EDTA) or DTPA—have been found to successfully decrease zinc levels in patients experiencing toxicity.
If zinc toxicity occurs due to inhaling metal fumes, treatment again focuses on supportive care. This might involve over-the-counter drugs to control fever, hydration, and anti-inflammatory medications. If needed, medicines to help you breathe easier (bronchodilators) and oxygen supplementation could be given.
Last but not least, chronic zinc toxicity, an ongoing exposure to high levels of zinc, is mainly treated with copper sulfate. Severe cases might also need the use of medicines that bind and remove zinc. In all scenarios, finding and removing the source of exposure is crucial.
What else can Zinc Toxicity be?
If a person suddenly takes in a large amount of zinc, they might start experiencing symptoms related to the stomach and intestines. Unfortunately, it’s not easy to figure out if zinc is causing this because the symptoms are very common and the person might not realize they’ve been exposed to high amounts of zinc. In more severe cases, too much zinc can look like many other health problems, and it might even cause serious issues like damages to your kidneys or pancreas, liver failure, or unstable blood flow.
Some other situations that might seem similar to severe zinc poisoning include severe infections that lead to shock, bleeding in the stomach or intestines, or having ingested other toxic substances. Hence, it can be difficult for doctors to consider zinc toxicity as one of the potential causes amid so many other common possibilities.
Things can get even more complicated when someone is exposed to smoke or fumes from zinc-based materials such as smoke bombs. It could cause severe breathing problems, a condition called acute respiratory distress syndrome. But this also happens in many other diseases, which makes it harder to identify if zinc is the real cause. The situation can be particularly tricky in workplaces where there’s regular exposure to metal fumes. Some workers might experience symptoms that look like an ordinary respiratory infection but are actually related to the fumes they are breathing in.
Long-term zinc poisoning should be considered if someone has iron-deficiency anemia that doesn’t get better with iron supplements. But just like the acute cases, there are many other more common reasons for anemia, like losing blood, not getting enough iron from diet, or having problems in the bone marrow.
For example, a condition named sideroblastic myelodysplastic syndrome, which does not get better with common treatments, can be caused by low copper levels due to chronic zinc overdosage.
What to expect with Zinc Toxicity
The chances of zinc toxicity leading to death are extremely low. However, the patient’s prognosis, or expected health outcome, largely hinges on how quickly they receive treatment. Large amounts of zinc intake on purpose are most likely to cause serious toxicity.
Possible Complications When Diagnosed with Zinc Toxicity
Zinc toxicity can cause several health problems. If you inhale too much zinc, you might experience recurring shortness of breath or inflammation of your air passages. If you consume too much, it could have effects on your digestive system, leading to dehydration and possible digestive bleeding. Other symptoms may include feeling extremely tired, having a lower than normal amount of red blood cells (anemia), and feeling dizzy.
Long-term exposure to too much zinc can affect your bone marrow (the spongy tissue inside your bones where blood cells are made) and can lead to a condition affecting the nerves in your brain and spinal cord (polyneuropathy) due to a related copper deficiency. Zinc toxicity also can disrupt the way your body metabolizes copper, which can cause anemia.
Taking too much zinc over a long period can also increase your risk of developing prostate cancer and dying from the disease.
Possible Complications of Zinc Toxicity:
- Recurring shortness of breath
- Inflammation of the air passages
- Effect on the digestive system, potentially leading to dehydration and digestive bleeding
- Feeling tired
- Anemia
- Dizziness
- Effect on bone marrow
- Polyneuropathy due to copper deficiency
- Disruption in copper metabolism, potentially causing anemia
- Increase in the risk of prostate cancer and prostate cancer-related death
Preventing Zinc Toxicity
If you’re taking zinc supplements or tablets that are easily available at most drug stores, it’s crucial to take precautions and read labels carefully. If you accidentally take too much of these supplements, particularly zinc sulfate tablets, you should seek immediate medical help. A common problem is also using too much denture cream, as it can cause you to consume too much zinc, which in turn can decrease your body’s copper levels. Therefore, always read the instructions on any prescribed or over-the-counter supplement or medication. If you think you’ve taken too much of your medication or supplement, reach out to a healthcare professional or a poison center immediately. Additionally, some beauty products contain considerable amounts of zinc and should be used mindfully.
