Diet and oral health

Nutrition & Food Science

ISSN: 0034-6659

Article publication date: 1 August 1999

363

Citation

(1999), "Diet and oral health", Nutrition & Food Science, Vol. 99 No. 4. https://doi.org/10.1108/nfs.1999.01799daf.003

Publisher

:

Emerald Group Publishing Limited

Copyright © 1999, MCB UP Limited


Diet and oral health

Diet and oral health

A major report organised by the British Nutrition Foundation on Oral Health: Diet and Other Factors was launched at a one-day conference in London at the beginning of the year. The relationship between types of foods and patterns of consumption and the risk of dental caries forms the basis of the report. At the conference expert members of the Oral Task Force who compiled the report presented papers. These included reviews of diet and caries, dental health in children, older people and other ‘‘risk groups’’, dietary associations with tooth defects such as erosion and with oral cancers.

Professor Mike Edgar spoke on the cause of caries and pointed out that caries result from the interaction over time of three factors: susceptible tooth tissues, oral bacteria in the form of dental plaque and dietary intake of fermentable carbohydrate, in practice essentially sugars, which can be converted to acid by plaque bacteria. The way to prevent caries is to restrict the frequency of intake of sugars and other easily fermentable carbohydrate foods. These should be consumed at meal times and not in between meals. Professor Edgar pointed out that cheese nullifies the drop in pH of the saliva after a sugary dessert. Peanuts have the same effect. Chewing sugar-free chewing gum after a meal stimulates the flow of saliva and neutralises the acidity in the mouth.

Professor Philip Holloway, Dental Health Unit, University of Manchester gave a paper on the epidemiology of caries starting with the fact that dental decay has been with mankind since antiquity. Ancient skulls discovered at burial sites and old pictures and writings provide us with this evidence. The earliest human skulls showed a destruction of the teeth beginning in the root surface facing the next tooth. The teeth of ancient Egyptians showed signs of caries and Roman centurians suffered from the disease. In both cases this was probably due to the effect of natural sources of sugar in figs, dates, sweet wine and other sweet delicacies. Dental decay was mainly a disease of adults and its prevalence was low and confined largely to small populations at risk.

The prevalence of caries remained low through the ages in this country but began to increase markedly in the middle of the last century when the duty on sugar was removed and the corn laws repealed. This rise was checked only briefly by the intervention of two world wars when sugar supplies were reduced. Another good example occurred on the island of Tristan da Cuhna. Prior to the Second World War, the islanders were isolated from the rest of the world and had a very limited diet mainly of fish and potatoes. With the advent of the war a British naval station was established on the island and the population were given access to the foods enjoyed by the service personnel. After the war a fish canning industry was established which increased the supply of imported food from South Africa. All this resulted in an increase in the availability of sugar and sugar products and over a short period of time dental decay changed from a rare disease confined to a few adults to a disease that quickly destroyed the dentition of infants.

In the UK and other Western European countries there has been a dramatic fall in the prevalence of caries over the last 25 years. The prevalence of caries in the UK dropped by nearly a half in pre-school children during this period, from 80 per cent affected down to 45 per cent. This has been among the most encouraging improvements in health experienced during this century and must rate as an important public health achievement. One likely reason for this change was the introduction of fluoride toothpastes. However there are still large geographic variations in prevalence. There is a marked increase in the disease as one travels from the south to the north of the country and levels in Northern Ireland are higher than anywhere else in the UK.

There are also large variations in prevalence among different socio-economic groups. By and large there are much lower levels of caries among people in social classes I and II than in IV and V. A combination of the use of fluoride toothpaste and the sensible use of sugar among groups at high risk might reduce the level of caries without the need for dramatic and possibly unattainable changes in lifestyles.

Professor Angus Walls of the University of Newcastle spoke about dental health in older people. The proportion of the population in the UK over the age of 65 is growing and this trend is expected to continue for the next 20 years. Three national surveys conducted in 1968, 1978 and 1988 showed a reduction in the numbers of people without their natural teeth and today 50 per cent of the over 65s have some natural teeth. However, problems of caries, tooth wear and periodontal disease are still encountered. In older people gums often recede leaving the teeth exposed and susceptible to caries. This is a particular problem of institutionalised older people among whom as many as 79 per cent may be affected. There is also a higher proportion of root caries among men, manual householders and those who rarely visit a dentist.

The number of teeth we have influences masticatory efficiency. While many modern prepared foods are easily chewed, we cannot digest what we do not eat. Difficulty in chewing hard foods such as apples, salads and crisply crusted wholemeal bread may lead to a poor intake of fibre, iron, vitamin C and other micronutrients. Masticatory efficiency depends on the number of natural teeth retained and is reduced by partial or complete dentures. It has been found that the intake of non-starch polysaccharides was reduced to 10 gram among a group of institutionalised older people with dentures.

Sally Craig, Child Dental Health, Sheffield spoke about tooth defects and erosion. Tooth defects may be pre- or post-natal and inherited or acquired. Defects of dentine formation are usually genetic in origin. Defects of enamel may occur when the process of mineralisation or matrix formation is disturbed and nutritional defects or excesses postnatally are a potential possible cause. Acidic drinks and foods can cause erosion. This is of particular concern when children are given them last thing at night after the teeth have been cleaned. It is estimated that consumption of soft drinks has increased 700 per cent since the 1950s. Teenagers with the habit of swilling the drink around their mouths increase the risk of erosion while a fine straw which takes the drink directly to the back of the mouth without touching the teeth may reduce erosion.

Erosion is a form of tooth tissue loss caused by a chemical process that does not involve bacteria as dental decay does. In a recent survey, half of five to six year olds showed evidence of tooth tissue loss on one or more primary incisors and among children of 11 years or over one-quarter or more were found to have some on the palatal surface of the upper permanent incisors. Recurrent vomiting such as that which takes place in anorexia bulimia is another cause of erosion. Advice to patients should centre on changing dietary habits, optimising oral health regimes, such as using a fluoride toothpaste, and obtaining treatment for any underlying medical conditions.

Professor Martin Downer, Eastman Dental Institute, London gave a paper on oral cancer. This condition is comparatively rare but has a high degree of morbidity and mortality. Its incidence varies in different parts of the world. For example, it is more common in India where chewing tobacco is thought to be a contributory cause and in France where consumption of crudely distilled spirits is more common. Oral cancer is the eighth most common cause of cancer in Western Europe and there are approximately 2000 new cases in England and Wales each year.

The combined effects of tobacco smoking and alcohol consumption which are not moderated by the protection afforded from a generous dietary intake of fresh fruit and vegetables appear to explain the majority of oral cancer cases in Western countries. Iron deficiency produces an increased risk while vitamins A, B,C, E and beta carotene have a protective effect. Observed increases are likely to be due to raised alcohol consumption during the last 40 years. Subjects who suffer peristent sore spots in the mouth or ulcers are advised to seek professional advice.

Concluding the proceedings Professor Pickard of the British Nutrition Foundation said that limiting the consumption of sweet foods to meal times, fluoridation of water supplies and the regular use of fluoride toothpastes could do a great deal to overcome the problem of dental caries.

Oral Health: Diet and Other Factors costs £70 and is available from Emma Dhesi, Publications Officer, British Nutrition Foundation, High Holborn House, 52-54 High Holborn, London WC1V 6RQ.

Related articles