Oral Health and Nutrition

Nutrition and diet affects the development and integrity of the oral cavity as well as progression of diseases of the oral cavity, and are major multifactorial environmental factors in the aetiology and pathogenesis of oro-facial diseases and disorders (US Department of Health and Human Services 2000). Oral health means more than good teeth; it is integral to general health and essential to well-being (Petersen 2003). The interrelationship between oral health and general health has been proven. Severe periodontal disease, for example, is associated with diabetes (Grossi & Genco 1998). The strong correlation between several oral diseases and noncommunicable chronic diseases is primarily the result of common risk factors (Sheiham W nutrition, including access to fluoride and use of sugar; composition and activity of the oral microflora; and a recognition of behavioural and biological impacts on health. Published research has looked at associations between key risk factors and the development of dental caries cross-sectionally and some longitudinally (Hausen 1998). However, in developing countries, little is known of the interactions vertically in the paradigm between molecular


Oral health and nutrition
There are few studies of the relationship between oral health and nutrition in very old people. In this issue of Age and Ageing, Mojon and colleagues show how collaboration between health care workers in the field of ageing can improve understanding and practice [1]. They identify oral problems in people in care homes, relate this to nutritional deficiency and advocate preventive measures. There are two aspects to the relationship between oral health and nutrition. The better known and more widely documented are the effects on the oral soft and hard tissues of foods and of nutrient deficiencies. These include oral mucosal atrophy associated with deficiency of the B complex vitamins, folic acid and iron. This may lead to oral infection with candida species and angular cheilitis (sores at the corners of the mouth).
The oral health of the ageing population is changing, with increasing numbers of older people retaining their natural teeth for longer. One might expect that the oral hard tissues would be spared from dietary influences. Unfortunately this is not so: teeth remain at risk from decay throughout life. The key determinants of decay are an individual's personal oral health care; the quantity, and particularly the frequency of intakes of fermentable sugars; and the individual's susceptibility to this disease.

Sugars and tooth decay
The sugar most often associated with decay is sucrose, but other sugars can cause problems-notably glucose, fructose and maltose. These naturally occurring carbohydrates have a lesser but still important cariogenic potential. Frequency of intake of more than 5-6 times daily should be avoided, including sugars taken to sweeten beverages. In a recent national survey of oral health and nutrition in people over 65, there were very high levels of unmanaged tooth decay. This was particularly so for those in residential care, where the diets were characterized by high levels and frequency of consumption of non-milk, extrinsic sugars [2]. Another source of sugars which may be of concern in the older patient are those which are part of the normal formulation of drugs (especially in syrup form, either prescribed or bought over the counter).
Teeth are also damaged by acid foods in the mouth, either in the form of drinks or fruit or during vomiting. Moderation in the frequency of intake of acid-rich foodstuffs is important.
The effects of sugars and acids on teeth are exacerbated if an individual has reduced oral defences, particularly altered salivary flow and function. Whilst this salivary flow is not thought to be affected by age alone, it is affected by diseases and notably by drugs [3].

Masticatory efficiency
The second association is the relationship between oral health status, chewing efficiency, food choice and nutrient intake. The ability to chew food effectively does not influence our ability to digest food with a modern diet [4,5]. However, our ability to chew food influences the foods we choose to eat. As chewing efficiency reduces, people choose to eat foods that require less mastication. Alternatively, they process their food to make it more easily chewed [2,6,7]. This results in marked changes in dietary intakes for some key nutrients, for example non-starch polysaccharides (fibre). The intake of intrinsic and milk sugars increases with increasing numbers of functional natural teeth, as well as do levels of micronutrients and vitamins [2,8]. Conversely, intakes of protein, intrinsic and milk sugars, calcium, non-haem iron, niacin and vitamin C are reduced in those who have no natural teeth compared with those who have some teeth [2,7,9].
These reductions in intake are associated with reduced biochemical markers of nutritional status, most notably for vitamin C. Whilst these reductions remain within the normal range for most population groups, Steele et al. [2] found disturbingly low median levels of vitamin C in edentulous residents of long stay care homes (11.4 mmol l -1 ).