Effects of dairy products on oral health

Abstract

Listen

Translate article

Dr Johansson has presented an excellent and fascinating review of the effects of milk and dairy products on oral health in Scandinavian Journal of Nutrition, issue 3, 2002 (1). Although milk is one of the more commonly eaten foods it has been the subject of remarkably little clinical research concerning its ine uence on oral disease. The composition of milk has been compared with that of saliva, and like saliva it harbours a multitude of antibacterial agents, including immunoglobulins, and possesses remarkable physical properties. There is growing evidence that the antimicrobial effects of saliva probably act in concert and that the separation of its constituents may not be the ideal way to investigate their effects; a similar situation may prevail with milk. There appears to be confusion in the minds of some paediatric dentists on the role of milk in cariogenesis. It is perhaps important to have a clear idea of some dee nitions. Cariogenic applies to any substance that promotes caries; non-cariogenic applies to agents that neither promote nor reduce the prevalence or incidence of dental caries. Cariostatic refers to substances that prevent or reduce the incidence of dental caries in the presence of a cariogenic challenge. It has been claimed that milk when given in a bottle may contribute to ‘‘nursing bottle caries’’ or early childhood caries. However, reports fail to account for the remainder of the diet that infants ingest, nor do they recognize the physical effect of the nipple, which obstructs the e ow of saliva (2‐4). All of the available evidence suggests that milk is simply non-cariogenic and may have modest cariostatic properties under well-dee ned circumstances. Desalivated rats given milk as a sole source of nutrition orally remained essentially caries free (2); these observations are consistent with the results on the pH effects of milk on dental plaque as cited by Johansson. Furthermore, caries induced by 4% lactose (the same concentration found in cow’s milk) far exceeded that observed in rats fed whole milk. It is also noteworthy that the number and extent of carious lesions induced by milk containing up to 10% added sucrose were signie cantly less than observed in rats given 10% sucrose in water (3). Under these circumstances milk exerts a cariostatic effect, i.e. it overcomes to a large extent the harmful effects of sucrose. However, if the animals are fed a normal cariogenic diet separately and offered milk to drink, a reduction in incidence of caries is not observed. Specie c constituents of milk, even in the presence of saliva, can be adsorbed on to hydroxyapatite surfaces and thereby affect pellicle formation. There is some evidence to suggest that the micelles in milk (similar to saliva) are adsorbed to salivacoated hydroxyapatite (pHA). Several constituents in milk have the capacity to adsorb to pHA, including phosphopeptides and glycosylated