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Bitter taste or any altered taste sensation is called dysgeusia. Feeling a bitter taste in the mouth or experiencing any altered taste sensation may not be a disease by itself, but rather a symptom of an underlying condition.
Most of the time, a bitter taste remains in the mouth after eating a pungent or sour food. That taste sensation goes away by itself after some time. However, if an underlying illness is present, then a bitter taste can be experienced spontaneously, even without eating any food.
In an article published in the American Journal of Medicine, the National Health and Nutrition Examination Survey (NHANES) 2011–2012 reported that more than 5% of the over 142 million US respondents experienced taste disorders, and increasing age was associated with the increasing prevalence of taste disorders. (1)
Common Causes for a Bitter Taste in the Mouth
People often develop a bitter taste in their mouth due to the following factors:
1. Gastroesophageal reflux disease (GERD)
GERD occurs due to the reflux of acidic juices produced by the stomach up into the esophagus, which is the muscular tube connecting the throat and the stomach. This regurgitation of the acidic stomach contents can render a bitter or sour taste in your mouth. (2)(3)
GERD often leads to an altered sense of taste and smell that is also common in gastroparesis, a chronic stomach motility disorder that prevents stomach emptying. (4)
3. Oral and dental causes
A bitter taste in the mouth can be the result of poor oral hygiene, gum disease, mouth ulcers, cavities, ill-fitting dentures, or fungal infections such as oral thrush.
4. Radiation therapy
This treatment modality can damage the taste buds, associated nerves, and/or salivary glands and can alter taste sensation. (5)
5. Chronic diseases
Diabetes, kidney disease, thyroid disease, and upper respiratory infections such as the common cold, sinusitis, and flu may sometimes affect the taste sensation. (1)
6. Nutrient deficiencies
Zinc, vitamin A, and vitamin B12 deficiencies can cause taste disturbances. (1)
Some sweet substances may taste bitter if consumed immediately after brushing the teeth, due to the ingredients (such as sodium lauryl sulfate) in some toothpaste. (5)
Abnormal taste sensations (salt, peppery, or sour) are seen during menopause in some women, along with burning mouth syndrome. (5)
9. Xerostomia (dry mouth)
This condition causes an alteration in taste sensation. (6) Dry mouth occurs when saliva production by the salivary glands is decreased, which may be due to medications, chemotherapy or radiotherapy, increased tobacco use, aging, etc.
Bitter taste in the mouth is usually accompanied by the following symptoms:
- Loss of sense of smell (1)
- Burning mouth syndrome – Burning, stinging, and/or itching of the mouth, especially the tongue, sometimes extending to the lips and other areas of the mouth (3)
- Nasal congestion (stuffy nose) (1)(7)
- Other altered taste sensations, such as a metallic taste in the mouth (1)(7)
- Dry mouth (1)
The treatment for an altered sense of taste depends on the underlying cause:
- If the bitter taste or any altered taste sensation is caused by medications, then reviewing the patient’s medical history and evaluating a change in medication is recommended.
- If it is caused by a chronic condition or underlying illness, then evaluation and treatment of the condition are recommended.
- Zinc supplementation is given to patients with a zinc deficiency, and according to some studies, it is even given in patients with unknown reasons for the taste alteration. (6) Taste sensation alterations due to radiation therapy or chemotherapy will gradually reduce in a few months after the cessation of treatment. Zinc supplementation might also be helpful in these patients. (6)
- A bitter taste in the mouth after tooth brushing or getting any dental treatment is transient and goes away on its own in a few hours.
Diagnosing the Underlying Cause
Identifying the exact cause for the bitter taste in your mouth is a multi-step procedure, which involves:
- Taking your medical history
- Reviewing your medications
- Examining your head, neck, and oral cavity
Subsequently, the doctor may order a few additional tests:
- Different kinds of taste tests are performed. The patient is asked to taste sweet, salty, sour, and bitter taste solutions and to identify their quality and intensity to assess the taste sensation.
- Swab tests are sometimes done if a bacterial or fungal infection is suspected. (5)
- In some cases, trauma or head injury may affect the nerves supplying the taste buds and may cause an altered or loss of taste sensation. In these cases, a CT scan or MRI may be required. (7)
- Blood tests and/or urine tests are performed to diagnose any underlying medical conditions.
Home Remedies and Self-Care Measures
Here are some common tried-and-tested tips and measures to reduce the bitter taste in your mouth:
- Maintaining good oral hygiene, which includes brushing twice a day, flossing, tongue cleaning, and using a mouth rinse, helps reduce the bitter taste if it is due to gum disease or other oral infections.
- Chewing sugar-free gum and drinking more water helps reduce dry mouth and the altered taste sensation. (6)
- Reducing the consumption of foods that taste metallic or bitter, such as red meat, coffee, and tea, will reduce the altered taste sensation. (5)(6)
- Eating a nutrient-rich diet that includes eggs, dairy, fish, fruits and vegetables will help. (6)
- Adding seasoning and spices to food enhances its flavor. (6)
A bitter taste in the mouth by itself does not cause any complications and is usually a symptom of an underlying condition. Treating the cause will automatically reduce this symptom.
However, some people may suffer a loss of appetite due to the altered taste sensation, which in turn causes:
- Unintended weight loss
- Reduced quality of life (1)
When to See a Doctor
A doctor should be seen if:
- There is a persistent bitter taste in the mouth or altered taste sensation.
- You are experiencing appetite problems and/or weight loss.
- You experience other symptoms such as loss of smell, burning or itching in the tongue, and dry mouth.
According to the Centers for Disease Control and Prevention (CDC) and some anecdotal reports, a new loss of taste or smell is a symptom of COVID-19. Research is still going on in this subject. It is always recommended to talk to a doctor if a recent loss of taste or smell is noticed. (8)(9)
Developing a bitter taste in your mouth is usually not a serious problem and can be resolved by evaluating the underlying problem and treating it. Good oral hygiene, a nutritious diet, and drinking lots of water are some of the most commonly recommended solutions.
A doctor should be seen if other symptoms are experienced or if there is any loss of appetite. In light of the new coronavirus pandemic, it is advised to see a doctor if any recent loss of taste or smell is noticed.