Why do I have a metallic taste in my mouth?

A metallic taste in the mouth is both unpleasant and concerning. It can develop suddenly or over time. Taste is important. It helps us discern the quality of food we eat and warns of ingesting potentially dangerous substances. When taste sensations are disturbed, it can lead to loss of appetite due to the unpalatable taste, which may result in malnourishment. Dysgeusia or parageusia is the definition of a distortion of the sense of taste. 

Alterations in taste or smell are usually a secondary process connected to other disorders. These can include:

• upper respiratory infections
• gastric reflux disease
• allergies
• nutritional deficiencies
• dementia  - Alzheimer’s disease
• head injury or damage to the central nervous system
• ageing can also alter taste perception

Experiencing a specific metallic taste is common and may be caused by upper respiratory infections, oral infections, indigestion, prescription medications, over-the-counter medications/supplements, pregnancy, dementia or chemical exposure.

What is a taste disorder? 

Classification of taste disorder may be based on the following:

• Epithelial Disorders – where there is a disorder of the oral mucosa or taste buds. For example, this might include a dry mouth, coated tongue, atrophic glossitis, burns, and exposure to toxic substances.
• Neural Disorders – where there is a defect in the way taste stimulus is transmitted due to neural disorders
• Central Disorders – due to such things as brain tumour, head trauma, Alzheimer’s disease or surgery, for example.

What causes a metallic taste in the mouth? 

Being able to resolve a metallic taste involves diagnosing and treating the cause where possible. 

Upper respiratory infections

The sensation of taste is controlled by taste buds found in the oral cavity of the mouth and the olfactory sensory neurons (in the nose) – responsible for smell.

Cold, influenza and infections involving the sinuses, nasal passages and tonsils can sometimes result in a change in taste. By treating the infection or virus, this should resolve the problem. Help clear congestion with inhalers, saline nasal rinses or nasal sprays. Support respiratory system health by supporting the immune system with zinc, vitamin C, echinacea, andrographis and elderberry.

Oral infection

Oral infections such as periodontitis, gingivitis, tooth infection and tooth fillings may be the cause of taste aberrations. A visit to the dentist is important to rule out dental/oral causes of metallic taste. Thorough dental hygiene, including brushing, flossing and tongue cleaning, is important to prevent changes in taste and recurrence. 

Indigestion

Gastro-oesophageal reflux may also leave a metallic taste in the mouth. Reflux can be influenced by both what you eat as well as how you eat. For example, coffee, alcohol, fatty or spicy foods, citrus, chocolate and peppermint can trigger symptoms in some, while eating large meals and lying down too soon after eating can also trigger symptoms. 

Medications

Saliva protects the external environment of taste buds within the oral cavity. It acts as a solvent and a transporter for taste substances. Many medications can cause changes in the saliva. Other medications will cause the taste buds to switch off. Check with your doctor whether your prescription medication could be the cause of your metallic taste.

Pregnancy

In the early stages of pregnancy, some women find their taste changes and metallic taste have been noted.

Dementia

Dementia is associated with changes in the function of the brain. Taste buds are connected by the nervous system to the brain, and if the part of the brain associated with taste is affected, it can interfere with taste perception.

What are the benefits of zinc?

It should be noted zinc is needed for both repair and maintenance of taste buds. It is needed for the production of gustin, also known as carbonic anhydrase VI, a protein linked to taste bud development.

When salivary gustin is deficient, smell deficient smell and taste can be affected. Zinc is a cofactor for an important enzyme, alkaline phosphatase, located in the membrane of the taste buds. Supplementing with zinc can treat these disorders.

Zinc is needed for the efficient functioning of the immune and digestive systems.

How do I get rid of the metallic taste in my mouth? 

Once the cause of the metallic taste in the mouth is identified, it may be resolved. Talk to your healthcare professional if you have any concerns are a metallic taste in your mouth. 

Related reads:

• What you need to know about zinc
• Why Can’t I Taste Anything?

References

1. https://www.nidcr.nih.gov/health-info/taste-disorders 
2. Thomas, D. C., Chablani, D., Parekh, S., Pichammal, R. C., Shanmugasundaram, K., & Pitchumani, P. K. (2021). Dysgeusia. Journal of the American Dental Association (1939), 153(3). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8595926/
3. https://www.nidirect.gov.uk/conditions/metallic-taste-mouth#toc-0 
4. https://www.nidcd.nih.gov/health/taste-disorders#3 
5. https://www.nidcd.nih.gov/health/taste-disorders#4 
6. Shaikh, F. H., & Soni, A. (2020). Physiology, Taste. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557768/
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9. Feng, P., Huang, L., & Wang, H. (2013). Taste Bud Homeostasis in Health, Disease, and Aging. Chemical Senses, 39(1), 3–16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864165/
10. https://www.healthdirect.gov.au/gord-reflux#treated 
11. Rademacher, W. M. H., Aziz, Y., Hielema, A., Cheung, K., Lange, J., Vissink, A., & Rozema, F. R. (2019). Oral adverse effects of drugs: Taste disorders. Oral Diseases, 26(1), 213–223. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988472/
12. Schiffman, S. S. (2018). Influence of medications on taste and smell. World Journal of Otorhinolaryngology - Head and Neck Surgery, 4(1), 84–91. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051304/
13. Boshra Mozaffar, Arash Ardavani, Hisham Muzafar, & Idris, I. (2023). The Effectiveness of Zinc Supplementation in Taste Disorder Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Journal of Nutrition and Metabolism, 2023, 1–13.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10017214/
14. https://www.betterhealth.vic.gov.au/health/healthyliving/pregnancy-signs-and-symptoms 
15. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dementia-eating 
16. https://www.betterhealth.vic.gov.au/health/healthyliving/mercury-exposure-and-poisoning 
17. https://www.betterhealth.vic.gov.au/health/healthyliving/Lead-exposure-and-your-health