IMPORTANT: In issues of oral health and dental care you should ensure your treatment, care, and support is provided by qualified and experienced health professionals. Check the register of the New Zealand Medical Council for Oral and Maxillofacial Surgeons (OMS) (Click here) and the register of the Dental Council of New Zealand for dentists, and prosthodontists.(Click here) Ensure the right health professional with the rights skills, and expertise is providing advice and services for your safety, health and well being. Be aware that this advice from the Ministry of Health does not include OMS that are registered with the Dental Council ONLY.

Hope for Dry Horrors

You know the feeling. You forgot your water bottle so you dash into the dairy to get a new one. You’re annoyed because bottled water is expensive and you have five empty bottles stashed at home.

When you approach the shopkeeper, you can barely talk because your tongue is stuck to the top of your mouth.

You kick yourself for coming out without water, gel, lozenges or gum. Dry mouth is unforgiving and you have to be prepared.

I’m actually a lucky post-radiation patient. I have plenty of saliva - just not in the right places and when I go out for a walk or mow the lawn my saliva just disappears because I’m breathing through my mouth. The rest of the time I drool out of my paralysed lip where the saliva I do have seems to pool. You can’t win.

Forty percent of us develop dry mouth after treatment, according to the article below. Sometimes there is an improvement in the first five years but in a few patients, saliva is gone for life. There are products that can mitigate the effect but no magic bullet.

That’s why everyone was excited when an article did the rounds last week announcing that a citrus peel extract could save saliva cells from radiation damage.

“D-limonene Found in Citrus Oil Could Reduce Dry Mouth in Cancer Patients”

The original study was called:

“Aldehyde dehydrogenase 3A1 activation prevents radiation-induced xerostomia by protecting salivary stem cells from toxic aldehydes”

Basically it is about a study at Stanford University which still has years to play out. Radiation therapy kills saliva cells, even the stem cells and progenitor cells, the ones that will eventually grow into mature saliva cells.

Radiation causes an increase in aldehydes which harm the cells. There's an antidote in our saliva called aldehyde dehydrogenase or 3A1 but this friendly compound is not enough to stop the aldehydes damaging the cells.

Doctors and scientists have found that an organic compound found in citrus oils can boost the 3A1 enzyme. It’s a common compound, D-Limonene, used by some natural health advocates as a supplement and by others as a cleaner. It could be harmful to take it long term off your own bat and it needs to be used by people undergoing radiotherapy before the cells are damaged.

The doctor who is carrying out the study with scientists listened to her patients for many years as they complained about their lack of saliva. Dr Rosen, testing on mice, found that the d-limonene reduced aldehyde concentrations in both adult and stem/progenitor cells .

How did she find the compound in citrus oil? She had access to 135 Chinese medicine extracts that had been used for 100s of years, boosting the likelihood they were safe. Seven of the extracts boosted 3A1 activity with the citrus compound being the most useful as it broke down quickly in the body and was deemed generally safe by the FDA.

NB This is just a study. 


Xerostomia = dry mouth

Hyposalivation = reduced salivary flow

Submandibular glands = saliva glands under lower jaw/chin

Aldehydes = toxic compound

Aldehyde dehydrogenase 3A1 = helpful compound

D-limonene = citrus oil extract that might boost the 3A1 compound.

PS some medical jargon from article.

Acute or chronic hyposalivation can impair speaking and swallowing and increases the risk of oral pain, ulcerations, infections, and dental caries. Submandibular glands contribute more than 60% of unstimulated saliva and are essential for resting salivation and oral lubrication. Despite advances in intensity-modulated radiation therapy for HNC, about 40% of patients develop xerostomia . Current treatments are suboptimal, limited to temporary symptom relief.

Diana Ayling

Dental and Oral Care

Before treatment we advise you to review these resources. We know that head and neck cancer patients can have many dental and oral care issues. We provide resources:

Before Treatment

During Treatment

After Treatment