Dairy Products and Dental Health

Dairy products and particularly cheese have very low cariogenic potential and are therefore safe for teeth. Small amounts of cheese (5-20 grams) are effective in reducing caries risk, especially if eaten at the end of a meal.

Bega Cheese

Introduction

Dental caries is a bacterial disease which begins in childhood. Bacteria form "plaque", a thin film, on the teeth and dietary components such as sugars, aid adherence of bacteria. Sugars are fermented to organic acids which dissolve the tooth enamel causing loss of calcium and phosphate (demineralisation) and eventually a cavity. Studies in rats have shown all simple sugars are equally cariogenic1 but human studies suggest lactose is less cariogenic.

Bottle Caries

Teeth are particularly vulnerable to acid attack between ages 0-2 years. Bottle caries can develop with chronic exposure of the teeth to fermentable sugars, eg, comforting with a bottle of milk or fruit juice. This allows the sugary liquid to pool around the teeth which may result in bacterial acid attack. Therefore it is generally recommended that bottle feeding be discontinued from 12 months of age.2

The Anti-Cariogenic Potential of Dairy Products

Many studies have shown a positive effect of dairy products on reducing dental caries. Cheese has been studied the most. Other dairy products, such as yoghurt an dice-cream, are also thought to have low cariogenic potential but have been less well studied.3 Human studies usually involve use of an intra-oral device containing bovine or human enamel as the test material.

Cheese

Fewer caries have been found in animals consuming additional cheese "snacks"4 and cheese consumption was found to be higher in children with fewer caries.5 Cheese has been shown to significantly reduce demineralisation (by 71%) caused by sugar6 and produce less enamel softening compared with bread.7 In addition, cheese can reharden softened tooth enamel after exposure to sugary or acidic foods.8,9 Cheese is likely to exert maximal benefit at the end of a meal.

It appears that harder cheeses are more effective than soft cheeses in caries prevention. However, most types of cheese have been studied and have some positive influence on the caries development process. As little as 5-20 grams of cheese is effective in reducing caries risk.

Milk

Milk has been shown to be less cariogenic in humans than fruit juice10 and to reharden softened enamel after coca-cola.11 Pasteurised, UHT, sweetened, reconstituted, whole and skim milk significantly reduced enamel softening by at least 22% after exposure to sucrose.12

Mechanisms of Action

There are several theories for the mechanisms involved int he caries protective effect of cheese. Cheese has been shown to reduce the numbers of the bacteria Streptococcus mutan3 and to stimulate saliva flow.13 This may reverse the caries process (ie, remineralisation) by saliva neutralising the acids and increasing the pH. A range of cheeses eaten before, with or following sugar have been shown to prevent or reverse the pH drop normally produced.6,8,14

Calcium, phosphate, and fluoride in saliva maintain a supersaturated state so inhibiting demineralisation and encouraging remineralisation. Cheese has been shown to increase the concentration of calcium and phosphorus or oral fluids, and this is not limited to cheeses high in calcium and phosphorus.15,16

The anti-cariogenic effect of cheese may also be via the protein or more specifically casein content. Casein may help buffer the plaque pH and also by adsorbing onto the tooth enamel may reduce enamel solubility and bacterial adherence. The caries protecting effect of 21 cheeses was tested using a rat model demonstrating those with higher casein content had the greatest effect.15 Casein and caseinate also have been shown to reduce to extent of caries in rats.

REFERENCES

  1. Shaw, JH, Krumins, F, Gibbons, RJ. Comparison of sucrose, lactose, maltose, and glucose in the causation of experimental oral diseases. Arch Oral Biol 1967; 12:755-68.
  2. Burgess, RC. Dental Caries. Can Fam Physician 1988; 34:1341-47.
  3. Curzon, MEJ. Food and dental caries. BNF Nutrition Bulletin 1989; 55:36-45.
  4. Edgar, WM, Bowen, WH. Amsbaugh, S et al. Effects of different eating patterns on dental caries in the rat. Caries Res 1982; 16:384-9.
  5. Rugg-Gunn, AJ. Jackett, AF, Appleton, DR, et al. Relationship between dietary habits and caries increment assessed over two years in 405 English adolescent schoolchildren. Arch Oral Biol 1984; 29:983-92.
  6. De Silva, MF, Jenkins GN, Burgess, RC, Sandham, HJ. Effects of cheese on experimental caries in human subjects. Caries Res 1986; 20:263-9.
  7. Thomson, ME. Effects of cheese, breadcrumbs and a breadcrumb and cheese mixture on microhardness of bovine dental enamel in intraoral experiments. Caries Res 1988; 22: 246-9.
  8. Jensen, ME, Wefel, JS, Effects of processed cheese on human plaque pH and demineralisation and remineralisation. Am J Dent 1990; 3:217-223.
  9. Gedalia, I, Ionat-Bendat, D, Ben-Mosheh, S, Shapira, L. Tooth enamel softening with a cola type drink and rehardening with hard cheese or stimulated saliva in situ. J Oral Rehab 1991; 18: 501-506.
  10. Dever, JG, Thomson, ME, Hampton, M. Fruit juice and flavoured milk effects on enamel in an intro-oral model. NZ Dent J 1987; 83:7-10.
  11. Gedalia, I, Dakuar, A, Shapira, L, et al. Enamel softening with coca-cola and rehardening with milk or saliva. Am J Dent 1991; 4:120-2.
  12. Thomson, ME, Dever, JG, Pearce, EIF. Intra-oral testing of flavoured sweetened milk. NZ Dent J April 1984:44-.
  13. Krobicka, A, Bowen, WH, Pearson, S, Young, RA. The effects of cheese snacks on caries in desalivated rats. J Dent Res 1987; 66:1116-9.
  14. Rugg-Gunn, AJ, Edgar, WM, Geddes, DAM, Jenkins, GN. The effect of different meal patterns upon plaque pH in human subjects. Brit Dent J 1975; 139:351-6.
  15. Pause, B, Lembke, J. Comparative examination of anti-caries effect of cheeses. II. Results and conclusions. Milchwissenschaft 1993; 48:137-41.
  16. Patocka, G, Hargreaves, JA. Release and retention of calcium and phosphorus from various dairy products in the oral fluid. Int Dairy J 1991; 1:101-10.
  17. Reynolds, EC, del Rio, A. Effect of casein and whey protein solutions on caries experience and feeding patterns of the rat. Arch Oral Biol 1984; 29:927-33.

Fact File is produced by the Dairy Advisory Bureau, nutrition advisors to the New Zealand Dairy Board. The information in Fact File reports may be reproduced or quoted provided attribution to the Dairy Advisory Bureau or the New Zealand Dairy Board is stated. For information on other titles in the Fact File series please contact the Dairy Advisory Bureau.