The Impact of Eating Disorders on Oral Health

Trigger warning: This article contains mentions of eating disorders which some readers may find distressing.

The impact of eating disorders on oral health is well documented, yet it remains an overlooked consequence of these complex mental health conditions. Research consistently shows that individuals with eating disorders often experience significantly poorer oral health than the general population, with an increased risk of dental erosion, tooth decay, gum problems, and dry mouth. Dentists are frequently among the first healthcare professionals to notice physical signs of underlying eating disorders, sometimes even before a patient feels able to disclose their struggles.

As a newly qualified dentist, my clinical experiences have highlighted how eating disorders can significantly affect oral health, prompting me to explore these often under-recognised consequences in greater depth.

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What Are Eating Disorders?

Eating disorders are psychiatric conditions characterised by abnormal eating behaviours and distorted relationships with food. Bulimia nervosa and anorexia nervosa are among the most recognised eating disorders and affect millions of individuals in the UK.

Bulimia nervosa is characterised by cycles of binge eating followed by compensatory behaviours aimed at preventing weight gain, such as self-induced vomiting, abuse of laxatives or diuretics, or fasting. In contrast, anorexia nervosa is defined by persistent restriction of food intake, resulting in significantly low body weight. While traditionally defined by restriction, some individuals with anorexia nervosa may also engage in purging behaviours such as self-stimulated vomiting.

Although these conditions differ in presentation, they both have serious and sometimes overlapping effects on oral health.

Tooth-wear and Acid Erosion

One of the most characteristic oral manifestations of eating disorders, particularly in individuals who self-induce vomiting, is dental erosion. Repeated exposure of the teeth to stomach acid gradually erodes enamel (the protective outer layer of the teeth), particularly on the inner surfaces of the upper teeth. This erosion pattern often reflects the path stomach acid takes during vomiting episodes.

As enamel erodes the underlying dentine becomes exposed, resulting in dental hypersensitivities, for example to cold drinks and air. Teeth may also become discoloured, become more fragile and be prone to chipping and structural damage, all of which can negatively affect oral health–related quality of life.

While tooth-wear is more common in bulimia, with individuals being up to four times more likely to show these changes, this pattern is also seen in patients with anorexia nervosa, particularly in those who engage in purging behaviours.

It is important to note that while these dental changes are indicative of eating disorders and should be dealt with accordingly, similar patterns can occur in other conditions, such as acid reflux. Therefore, while dental changes are helpful, dentists should not solely assume someone has an eating disorder based on one appointment, and further sensitive conversations are needed in order to provide support to individuals.

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Additional Oral Effects

Purging behaviours can also cause trauma to the soft tissue in the mouth due to repeated stimulation of the gag reflex.  Dentists can often recognise this as bruising or injury to the palate (roof of the mouth) during dental check-ups.

In addition, patterns of binge eating which typically involve high-sugar foods can increase the risk of tooth decay. When combined with the acidic environment created by vomiting it can create a particularly harmful environment for teeth. This is because vomiting temporarily lowers the oral pH accelerating the early stages of tooth decay called demineralisation and subsequent erosion.

Moreover, mental health challenges associated with eating disorders, such as depression and anxiety, can also impact oral hygiene. Low mood, fatigue, fear of judgement, and diminished motivation can sometimes make daily self-care, including brushing and dental visits, feel overwhelming, which can increase the number of visible dental changes. As oral health deteriorates, individuals may experience feelings of shame which reinforces the secrecy of their eating disorder. The cognitive-interpersonal model of anorexia nervosa highlights these psychological symptoms and demonstrates how low self-esteem, social comparison, and emotional regulation difficulties can perpetuate the illness.

During my early experiences as a dentist I have encountered patients who have confided in me about their history of disordered eating, which has allowed me to recognise the importance of establishing rapport and building trust with patients to help them feel comfortable enough to disclose such information.

It is therefore important for different healthcare professionals to treat patients on an individual basis to help them feel more confident in various areas where they may be struggling.

The Role of Medications

While behaviours of disordered eating play a large role in dental hygiene, many individuals are prescribed antidepressant medication, particularly selective serotonin reuptake inhibitors (SSRIs). A common side effect of these medications is dry mouth.

Saliva plays a vital role in protecting oral health by neutralising acids, aiding in remineralisation, and controlling bacterial growth. Reduced saliva flow makes it harder for the mouth to repair early damage, increasing vulnerability to tooth decay and infection.

Dry mouth symptoms are often addressed with advice such as regularly sipping water throughout the day, using saliva substitutes such as over-the-counter gels, or using sugar-free chewing gum to stimulate salivary production. However, this issue is often compounded by malnutrition and dehydration, which can further decrease salivary production, exacerbate the effects of medication, and weaken the body’s natural defence system. As a result, the mouth becomes more vulnerable to disease and it becomes harder for the body to fight oral infections and heal.

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How Dentists Can Support Patients

Dentists play a vital role in identifying and supporting individuals who may be struggling with eating disorders. A key first step is understanding a patient’s current oral hygiene routine and providing individualised advice to help improve it.

For patients who purge, practical guidance can help minimise damage. For example, brushing teeth immediately after vomiting should be avoided for at least sixty minutes after vomiting so as not to agitate the stomach acids on their teeth. Instead they could rinse thoroughly with water which may help prevent further erosion to their teeth. Dentists could also prescribe high-fluoride toothpaste to help protect teeth against decay. In addition to daily advice, dentists should make appointments every 3-6 months to monitor any erosive tooth wear.

It may be useful for dentists to start by educating the patient on oral hygiene and the effects of neglecting self-care. This can be done in the same way psychoeducation is used in psychiatric and psychological practices when explaining a diagnosis to the patient.

A Holistic Approach to Care

While dentists and medical doctors may seem to be a world away, oral health does not exist in isolation from mental health.

Eating disorders can have profound effects on individuals as they may report reduced quality of life due to tooth pain, functional impairment from erosion or decay, and dissatisfaction with their dental appearance. This can impact them psychosocially as these dental changes may affect their eating, speaking, and smiling, and for individuals already struggling with body image, these changes in dental appearance and possibly smile dissatisfaction may further impact their self-esteem and social confidence.  

Patient readiness and shared decision-making must be at the forefront of prevention and management strategies, ensuring that oral health advice is delivered in a supportive, realistic, and patient-centred manner. This highlights how vital it is for psychiatry and mental health professionals to be aware of the dental effects of eating disorders, and even mood disorders such as depression, to promote oral health.