In the UK, mouth cancer is the 8th most common cancer, with 13,000 new cases diagnosed in 2019, and last year, 3,034 people in the UK died from mouth cancer.
A large proportion of cases, around 90%, are linked to modifiable risk factors – these are factors related to lifestyle or our environment that could be changed. While the most-known causes are tobacco smoking and human papillomavirus (HPV) infection, around 1 in 3 cases of mouth cancers are estimated to be linked to an unhealthy diet, including drinking alcohol and not eating enough vegetables.
In support of Mouth Cancer Action Month, we explore the evidence and recommendations on diet, body weight and mouth cancer.
What are mouth cancers?
Mouth cancer (also known as oral cancer) refers to cancers that develop in a part of the mouth, typically on the surface of the tongue, lips, gums, tonsils, lining of the mouth and the throat, and can also develop in the glands that produce saliva. Mouth cancer typically falls under the umbrella term of “cancers of the head and neck”, which includes different cancers of the nose, mouth and throat.*
Mouth cancer can develop as a result of genetic alterations that can lead to small, localised lesions growing abnormally in the inner lining of organs, such as the mouth.
Our expert findings
In our 2018 Diet and Cancer report, an independent panel of experts concluded there is strong evidence that drinking alcohol, and being overweight or living with obesity, increase the risk of mouth cancer.
There is also evidence, though limited, that drinking mate – a drink brewed with boiled water that’s common in parts of South America – increases risk.
The good news is that there is evidence that a healthy diet, eating non-starchy vegetables and coffee may decrease the risk of mouth cancers.
The risks of alcohol and weight
The mouth is directly exposed to carcinogens – compounds that can cause cancer – when we eat and drink. Alcohol consumption is linked to a third of all mouth cancers, yet the ways in which alcohol affects mouth cancer risk are not fully understood. Alcohol, or ethanol, is broken down in the liver and the main harmful substance formed is acetaldehyde.
All types of alcoholic drinks (including beers, wine, sprits, liquors, and alcopops) contain ethanol, and therefore are broken down into acetaldehyde. Acetaldehyde disrupts DNA synthesis and repair and may lead to a cascade of cancer-causing effects.
Alcohol may also function as a solvent for other known cancer-causing compounds, such as tobacco. For this reason, drinking alcohol and smoking together increases the risk of mouth cancer more than if an individual either smokes or drinks. Men are more likely to get mouth cancer than women, largely due to that on average, men tend to drink more alcohol and are more likely to smoke than women.
The way that overweight or obesity increases the risk of and cancers of the mouth are also not fully understood. Overweight and obesity have been shown to stimulate an inflammatory response in the body, which may promote the formation of tumours.
Overweight and obesity are also associated with too much insulin circulating around the body and higher levels of the hormone oestrogen, which have both been shown to lead to cancer cell growth and division, and reduced cell death among cancer cells.
Diet and mouth cancer
A healthy dietary pattern is a diet that’s likely to includes lots of fruit and vegetables, and little, if any alcohol, red and processed meat. Eating in this way is linked to lower risk of mouth cancers. Examples of such dietary patterns include the Mediterranean diet and following our Cancer Prevention Recommendations.
It’s likely that many individual components of healthy dietary patterns contribute to protection against these cancers. For example, fruit and vegetables contain beneficial nutrients and plant chemicals, known as phytochemicals. There is a strong body of research demonstrating the anti-tumour effects of the vitamins and minerals found in fruits and vegetables, such as vitamins A, C and E, carotenoids and selenium.
How to reduce mouth cancer risk
To reduce the risk of mouth cancer, we recommend:
- Not smoking or using tobacco in other ways, such as chewing tobacco
- Avoid drinking alcohol
- Stay a healthy weight
Importance of early detection and dental care
Early diagnosis of cancer can significantly help to improve survival. Checking your mouth for signs of mouth cancer, as well as regular dental visits, can help to detect mouth cancer early. In the UK, around 60% of adults have never checked their mouth for signs of cancer, with 19% conducting a quick check only once a month.
Oral diseases, including mouth cancer, disproportionally affect socially disadvantaged members of society. Alongside improving awareness of risk factors, public health policies addressing smoking, alcohol and diet are an effective way to reduce mouth cancer. Globally, fair access to dental care is also necessary for prevention and improving outcomes.
Our research on mouth cancer
Alongside analysing research, World Cancer Research Fund are also funding new research on diet, physical activity and mouth cancer. Prof Nicholas Timpson, at the University of Bristol, is leading a study to identify if overweight or obesity affects survival among people with head and neck cancers following treatment.
Prof Anne May, at the University Medical Centre Utrecht, is conducting a feasibility study of a 10-week exercise intervention during chemo-radiotherapy for head and neck cancer patients, investigating uptake, adherence, tolerability and participant satisfaction.