Diabetes and Dry Mouth: How Are They Related?

Dry mouth is one of the first symptoms of diabetes to be detected. Unfortunately, it's very uncomfortable for patients and predisposes them to the appearance of oral diseases.
Diabetes and Dry Mouth: How Are They Related?

Last update: 24 June, 2021

Diabetes is a metabolic disease associated with severe complications in the heart, kidneys, brain, and eyes. However, this pathology can also cause conditions in the mouth and gums. Are you interested in knowing how diabetes and dry mouth are related? Next up, we’ll tell you.

The sensation of dry mouth in which the person perceives a partial or total lack of saliva is known as xerostomia. Studies estimate an incidence of more than 20% in those over 60 years who suffer from chronic diseases. Similarly, dry mouth is usually a typical symptom of diabetes that can bring complications such as gingivitis or periodontitis.

Dry mouth symptoms

Diabetes and dry mouth are usually temporarily solved by drinking water
Diabetic people with some type of metabolic lack of control often require large amounts of water to quench their thirst.

Saliva is essential in the maintenance and protection of oral health. It helps to preserve your teeth, eliminate harmful agents, and regulate the pH of the mouth as well as swallowing.

When there’s a deficiency of saliva due to diabetes, this produces an uncomfortable sensation of dry mouth that affects the diabetic person at night or upon waking. Similarly, dry mouth produces the following symptoms:

  • Dry, pale, and chapped lips
  • Burning in the mouth and gums
  • Pain in the oral cavity
  • Difficulty chewing, swallowing, and speaking
  • Rough, dry, and pale tongue
  • Canker sores or ulcers

On the other hand, patients with diabetes who also suffer from dry mouth often have recurrent oral infections such as gingivitis, as well as cavities and the loss of tooth enamel. All this occurs as a result of the alteration of the oral microbiota, as well as affecting the structure of the gums and teeth.

What can cause dry mouth in diabetes?

Diabetes mellitus is a condition characterized by high levels of sugar or glucose in the blood. This fact favors the appearance of the typical symptoms of diabetes and can cause complications in the short and long term.

Generally, the dry mouth sensation present in patients with type 1 and type 2 diabetes is the result of an increase in the frequency and volume of urination. In this sense, excess blood sugar causes renal urine filtration, thus increasing fluid loss and raising plasma osmolality (the body’s electrolyte-water balance).

This situation produces a state of relative dehydration that alters the production of saliva, both in quantity and composition. When there’s a deficiency in saliva, the mucous membranes of the oral cavity lose their moisture and the patient with diabetes develops the sensation of a dry mouth.

Similarly, it’s common for the person to have an urgent need to drink liquids or polydipsia, a symptom that’s a fundamental part of the three “Ps” of diabetes.

This research affirms that saliva deficiency can contribute to periodontal diseases and worsens glycemic control. Similarly, there are other conditions that can occur in diabetics that promote and enhance dry mouth, among which we find are the following:

Diabetic sialosis

Sialosis is a disease of the saliva-producing glands that manifests as a painless, bilateral enlargement of the major glands. The parotid gland is the most affected gland, and its main symptom is the sensation of dry mouth.

In the long term, diabetes can alter the structure and functioning of these glands, compromising the excretion of saliva. Studies suggest that sialosis is common in chronic alcoholic patients and diabetics. However, in patients with diabetes the glandular enlargement is greater due to the infiltration of fat.

Renal problems

Kidney damage is one of the most feared complications of diabetes mellitus. In the advanced stages of the disease, hyperglycemia damages kidney membranes and tissues, affecting regular kidney filtration. For this reason, there’s a progressive increase in fluid loss as well as in the intensity of dehydration of those affected.

As a result, the person with diabetes will experience increased thirst, a dry mouth sensation, pale skin and mucous membranes, as well as alterations in consciousness. For this reason, periodic control of the disease and blood glucose is essential in order to avoid end-stage renal failure.

On the other hand, nephrogenic or central diabetes insipidus can alter the renal capacity to excrete urine. This is a less common form of diabetes caused by a dysregulation of antidiuretic hormones. It’s responsible for concentrating the urine and preventing fluid loss, and thus stimulates the excretion of large amounts of diluted urine and creates extreme thirst.


Diabetes and dry mouth are linked to drug use.
People with diabetes often have other associated pathologies. Some of the drugs taken can cause xerostomia.

In general, some drugs used in the management of diabetes and its associated conditions can cause a sensation of dry mouth as a side effect. Such is the case with metformin, an oral hypoglycemic agent commonly used in the management of type 2 diabetes. This medicine is associated with adverse effects such as tiredness, dry skin, dry mouth, and drowsiness.

In addition, the high blood pressure that usually accompanies diabetes is treated with medications that can cause dryness in the oral cavity.

These include diuretic drugs and angiotensin-converting enzyme (ACE) inhibitors. For this reason, it’s necessary to consult a doctor and get to know the treatment options and the associated effects.

Dietary ketosis

Dietary ketosis is a carbohydrate deficit with increased fatty acid metabolism induced by maintaining a ketogenic diet. Studies show that this diet is a popular option for patients with type 2 diabetes.

When following the ketogenic diet, there’s an increase in glycogen release and fluid loss. Because of this, it usually causes a sensation of dry mouth and dehydration in patients with diabetes.

In this sense, it’s important to consult a specialist regarding any food plan that you’re following, as well as notifying them if you’re suffering from any discomfort that may indicate you should stop that particular diet.

Diabetic cetoacidosis

Diabetic ketoacidosis is a common complication in type 1 diabetics. It is typically characterized by hyperglycemia, hyperketonemia, and metabolic acidosis. It occurs due to the insulin deficiency that induces the metabolization of fatty acids and the production of ketones for energy.

High blood sugar and acid levels promote osmotic diuresis and fluid loss. In this sense, the person may suffer from vomiting, nausea, dry mouth, dry skin, respiratory distress, sensory disturbance, and could even go into a coma. This alteration can also manifest itself in some patients with type 2 diabetes.

Dry mouth treatments in diabetes

In most patients with diabetes, proper control of blood sugar levels is the main way to relieve dry mouth symptoms. Similarly, it’s vital to identify and address other pathologies that may be contributing to the development of this symptom.

The National Institute for Dental and Craniofacial Research (NIDCR) recommends the following guidelines to avoid dryness and maintain oral health:

  • Ensure adequate water intake throughout the day
  • Avoid consuming sugary or salty foods and drinks
  • Reduce or eliminate caffeine consumption
  • Avoid excessive consumption of cigarettes and alcohol
  • Use humidifying equipment at night or at work
  • Consume the medications recommended by the dentist or treating physician
  • Practice proper dental hygiene, brushing your teeth twice a day, and flossing regularly

A condition that shouldn’t be underestimated

Dry mouth is a common condition in diabetes patients that often causes discomfort and discomfort during the day. In general, people tend to overlook this symptom and not pay too much attention to it. However, we should take into account that oral dryness is directly associated with dehydration and hyperglycemia.

For this reason, these symptoms are an early sign that something is wrong. If you start to suffer from dry mouth or other unusual symptoms, don’t hesitate to seek medical attention. Health professionals are trained to treat your condition and give you all the help you need.

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