Facts and Statistics 

Research shows that Dry Mouth (Xerostomia) symptoms are frequent among people with diabetes. Nevertheless, studies have not conclusively demonstrated that the prevalence in diabetics is higher than in people without diabetes.1 There are many co-existing factors that can cause salivary gland disorders in people with diabetes including age, other auto-immune disorders, head and neck cancer treatments, systemic disorders and medications.3 Recent research shows:

  • The parotid gland (fig. 1) is one of the larger salivary glands which releases saliva into the mouth. Dry mouth symptoms associated with parotid gland enlargement affects nearly 25% of patients suffering from moderate to severe type 1 or type 2 diabetes.
  • A 2016 systematic review showed higher prevalence of dry mouth symptoms in people with diabetes compared to those without the disorder. Overall prevalence rates were 12.5-53.5% in people with diabetes compared to 0-30% in those without the disease.
  • Studies also indicate that patients with poorly controlled diabetes have a higher prevalence to dry mouth symptoms than those with well controlled diabetes, 54% versus 47%, respectively.

 What is Dry Mouth? 

  • Dry mouth – known clinically as Xerostomia – occurs when the salivary glands do not produce sufficient saliva to keep the mouth moist, causing tissues in the mouth to become inflamed and sore. It can make chewing, tasting, and swallowing more difficult, as well as cause difficulty in eating, making it more difficult to control blood sugar.

Some clinical signs of Dry Mouth 

  • Loss of moisture, glistening of the oral mucosa
  • Dryness of the tongue, gums and palate.
  • Irritated corners of the mouth (cheilitis)
  • Gingivitis
  • Side effects of medication
  • Neuropathy ( autonomic)
  • Lack of hydration
  • Kidney dialysis
  • Hyperglycaemia
  • Mouth breathing
  • Smoking

Why Does diabetes cause Xerostomia? 

Experimental trials have shown that insulin abnormalities have indirect and direct effects on the function and structure of salivary glands.2 This may be due to unstable blood glucose levels impeding the salivary glands’ ability to release adequate saliva into the mouth.2

Some of the oral diseases experienced by diabetics can be attributed to Xerostomia. In addition however, the saliva secreted by the parotid glands contains excessive amounts of unabsorbed glucose, which further contributes to the deterioration of teeth, gums, and overall oral health, leading if untreated to periodontal disease.

Dental decay starts when different types of anaerobic bacteria adhere to tooth enamel, the gums, the tongue and the back of the throat — places where there is only a small amount of oxygen. These bacteria produce very high levels of sugar-based acids which can accelerate rates of dental decay and gum disease. Diabetics are at a significantly higher risk of dental disease than non-diabetics.

Moreover, people with diabetes often complain of bad breath and unusual, unpleasant taste sensations. This is due to the presence of sulphide molecules, particularly at the back of the tongue, where bacteria can thrive. These molecules are responsible for bad breath and taste disturbances.

If left untreated, persistent Dry Mouth can lead to many oral health issues including gingivitis and gum disease. People with diabetes need to take special measures to reduce Dry Mouth symptoms by limiting glucose intake, maintaining a healthy weight, regularly monitoring insulin levels, and following a daily oral care regime which can help control the nature and presence of these harmful bacteria.3


Sudden onset mouth dryness and thirst in diabetes 

It is important to differentiate between clinical Dry Mouth and the phenomenon of sudden unquenched thirst and its associated feeling of dryness in the mouth.

Even though diabetics can suffer from oral dryness, the opposite is not true. People suffering from Xerostomia are not necessarily diabetic.

Nevertheless, one of the first warning signs of diabetes can be the feeling of intense thirst (Polydipsia) due to excess glucose in the body causing an over-function of the kidneys, increasing urination (Polyuria) and a need for the body to have more water to dilute the sugar.4 This is a diabetic crisis alerting the patient to an imbalance in insulin and the need to take the appropriate steps to control this problem.

This phenomenon is not the same as Xerostomia and does not feel the same as Xerostomia. The former can be assuaged by drinking water and controlling blood glucose. The latter is persistent, difficult to alleviate and is linked to a gradual deterioration in oral health.

In conclusion, symptomatic control of the significant oral implications associated with diabetes requires effective, long term management and the inclusion of targeted oral care, including Dry Mouth relief, in a diabetic’s daily treatment plan.


1. J Diabetes Res. 2016; 2016: 4372852. Xerostomia, Hyposalivation, and Salivary Flow in Diabetes Patients. Rosa María López-Pintor, Elisabeth Casañas, José González-Serrano, Julia Serrano, Lucía Ramírez, Lorenzo de Arriba, and Gonzalo Hernández 
2. Biomedical Reviews 1998; 9:107-119. Salivary Gland Structure And Function In Experimental Diabetes Mellitus. Leigh C. Anderson Department of Oral Biology, University of Washington School of Dentistry, Seattle, Washington, USA 
3. Am J Med Sci. 2013 Apr; 345(4): 271–273. Oral Health and Type 2 Diabetes Renata S. Leite, Nicole M. Marlow and Jyotika K. Fernandes 
4. Am J Physiol. 1989 Mar;256(3 Pt 2):R597-604. Effect of blood glucose concentration on osmoregulation in diabetes mellitus. Thompson CJ1, Davis SN, Baylis PH.