Zinc Toxicity 

Introduction 

Zinc plays a vital role as a dietary nutrient in various bodily functions. However, excessive consumption of zinc can have detrimental effects, leading to symptoms like nausea, diarrhoea, and headaches. It is worth noting that most multivitamins contain zinc, which is essential and relatively safe in this form. Additionally, zinc can be obtained through dietary sources. Nevertheless, zinc can become toxic when combined with certain materials, such as paint and dyes. Excessive zinc intake can result in toxicity, causing gastrointestinal discomfort and potentially disrupting the balance of other chemicals in the body, such as copper and iron.

What is Zinc?

Zinc is a crucial nutrient that can be sourced from a range of plant and animal-based foods and supplements. It is vital for maintaining healthy skin, supporting immune function, and promoting cell growth. Additionally, it may offer protection against inflammation, acne, and other health issues. As your body cannot produce zinc alone, it is necessary to obtain it through dietary sources or supplements.

Benefits of Zinc

Zinc has a variety of benefits for the body, some of them are:

1. Zinc serves as a co-factor in enzymatic reactions that play a crucial role in DNA expression and membrane stabilization.
2. Vitamin A metabolism
3. Gustatory system
4. Olfactory system
5. Its multifaceted functions are also vital for fetal growth and development.
6. Zinc’s inverse relationship with copper levels is another notable feature of its role in the body. 
7. It is frequently included in pharmaceutical preparations for treating Wilson’s disease. 

Zinc Toxicity & its Side Effects 

Zinc is a crucial co-factor in the human body for proper functioning. However, excessive amounts of zinc can be harmful. Symptoms typically do not become apparent until ingestion surpasses approximately 1 to 2 grams of zinc.

There are three ways in which toxicity can occur: 

• Inhalation 
• Ingestion
• Skin contact 

Chronic zinc toxicity primarily manifests as copper deficiency. However, exposure and toxicity are common due to the abundance of zinc sources in the environment. 

There have been reports of toxicity resulting from:

1. Inhalation from occupational sources

Inhalation toxicity can vary in severity depending on the specific compound involved and the duration of exposure. For instance, smoke bombs containing zinc chloride can result in chest pain, airway irritation, and even a clinical presentation resembling acute respiratory distress syndrome (ARDS) with long-term pulmonary fibrosis as a consequence. Conversely, Inhaling zinc oxide can lead to a condition called “metal fume fever,” which usually occurs due to occupational exposure. In such cases, individuals exposed to fumes from welding, alloy production, and metal soldering may experience flu-like symptoms, cough, and shortness of breath, likely due to zinc’s direct impact on the pulmonary epithelium.

2. Overuse of dietary supplements

High levels of zinc intake can lead to various negative consequences, including,

• Feelings of nausea
• Vomiting
• Decreased appetite
• Abdominal cramps
• Diarrhea
• Headaches

Prolonged excessive consumption of zinc can result in chronic effects such as:

• Reduced copper levels
• Changes in iron function
• Compromised immune function

It is important to note that zinc can also interact with specific medications, such as, 

• Antibiotics
• Diuretics
• Penicillamine (a drug commonly prescribed for rheumatoid arthritis treatment)

3. Use of denture cream

Denture adhesives, whether in pastes, powders, or adhesive pads, are utilized to secure dentures in position. These adhesives may sometimes include zinc to improve their adhesive properties. 

However, excessive use of denture adhesives containing zinc, particularly when combined with zinc-containing dietary supplements and other sources of zinc, can result in an excessive accumulation of zinc in the body, leading to zinc toxicity. 

4. Ingestion of pennies due to PICA

It is not uncommon for children to accidentally ingest small coins, but the same cannot be said for adults. It is crucial to be aware of the risks associated with coin ingestion in adults who have severe developmental disabilities, mental illness, or dementia. Unfortunately, diagnosis often comes too late, resulting in fatal consequences.

5. Incorrectly prepared Total Parenteral Nutrition (TPN)

Total Parenteral Nutrition (TPN) is a type of intravenous nutrition that is the sole source of nourishment for patients. It is recommended for patients with gastrointestinal dysfunction and those who cannot receive enteral nutrition due to contraindications.

When TPN solutions are supplemented with zinc and the recommended dosage is followed, the risk of toxicity is minimal. However, excessive amounts of zinc can lead to toxicity in some cases.

6. Dermal exposure

Toxicity from zinc oxide can occur through dermal exposure, particularly from excessive use of makeup, sunscreen, and ointments. 

Treatment for Zinc Toxicity

If you may be experiencing zinc poisoning, contact a doctor immediately. Zinc poisoning is potentially life-threatening. It’s essential to seek medical help right away. 

The majority of cases involve acute toxicity, which can be treated with chelation therapy or medication prescribed by a doctor. In most cases, doctors can treat zinc poisoning with supportive care. Medicines can help manage symptoms and reduce the amount of zinc the body absorbs.

For example, to help stop zinc from being absorbed through the stomach, a doctor can recommend H2 blockers or proton pump inhibitors to lessen stomach acid production.

In some instances, a doctor may use an IV drip to inject a drug called calcium disodium edetate. This medication assists in getting rid of extra zinc from the body by binding it to the blood. The body then expels it via urine rather than binding to other cells. This is known as chelation therapy.

If a person has accidentally swallowed items consisting of zinc, they may require surgery to remove them.

Medicines are also given to treat the physical side effects of zinc poisoning. For example, doctors can treat zinc poisoning from oral ingestion with antiemetics to reduce vomiting and nausea.

If someone has zinc poisoning because of Inhalation, doctors may prescribe medications to reduce flu-like symptoms and keep airways open.

Conclusion

High doses of zinc can lead to acute gastrointestinal symptoms like vomiting, diarrhoea, and abdominal pain. In severe instances, it can even result in gastrointestinal corrosion and bleeding. Prolonged usage, on the other hand, may cause less immediate but still significant side effects such as low HDL (good) cholesterol, copper deficiency, and a weakened immune system. Sometimes, it may even lead to death. It is essential to consult a doctor before taking any supplements, even if you ingest a high dosage of zinc by mistake. 

FAQs