Dental disease affects what we eat; what we eat affects dental health. Damage to teeth is caused by different foods and dietary patterns, and advice to reduce the risk of dental disease is based on the outcomes of research, and observing dental health patterns in the population.

 

Dental caries, (cavities), is due to the damaging effects of acid produced by bacteria on the teeth. When the pH of the tooth surface falls below 5.7, the outer enamel layer of the tooth surface begins to demineralise; when this happens frequently over time, the damage causes permanent loss of enamel and exposure of sensitive inner layers of the tooth, eventually leading to pain and the need to remove the tooth. Carbohydrates can all contribute to acid production by oral bacteria, but in practice foods containing the sugars sucrose, glucose and fructose are most likely to lead to acid production on the tooth surface. Sugars found in milk and dairy foods are less cariogenic (likely to cause caries) and effects may also be moderated because dairy foods contain calcium, proteins and phosphates, which all help to neutralise acid production. Because the period of time a tooth is exposed to acid is the main dietary predictor of caries risk, the main food association is the frequency rather than the total amounts of sugars eaten: small amounts of sugar consumed frequently over time will cause more caries risk than the same amounts of sugar consumed at one intake.

 

Another diet associated caries risk is food texture: dried fruits such as raisins are sticky and small parts can wedge between teeth for a long time providing a constant slow release of sugars for oral bacteria; this is less likely to occur with fresh fruit or with sugars from drinks.

 

In addition to the damage caused by bacterial acid production linked to the frequent dietary intakes of sugars, damage to tooth enamel can also be caused by the direct actions of acids contained in foods. Dental erosion has been reported with increased frequency, particularly in children, and this may be due to the greater consumption of acid-containing drinks: fruit juices, ‘smoothies’ and soft drinks acidified with citric and phosphoric acids. While fruits such as citrus fruits also result in enamel erosion, the many nutrition benefits continue to support eating these fresh foods. As with cariogenic effects, the frequent expose to small amounts of acidity results in greater erosion than single occasion consumption. After eating acid foods the tooth surface is temporarily demineralised and soft, but in a short time saliva helps to remineralise the tooth: it is important not to brush teeth immediately after consuming acidic foods or drinks, as this may remove dissolved minerals and increase erosive damage. Another suggestion to reduce the direct erosion of teeth is to consume acidic liquids through a straw.

 

Diet forms an important component in supporting dental health behind the caries-protective effects of water fluoridation and the good dental hygiene practices of correct tooth brushing at least twice a day using a fluoride-containing toothpaste. More frequent tooth brushing and the less frequent consumption of sugary foods will both support a further reduction in dental caries rates in the UK population.

July 2006