Effects of cheese extract and its fractions on enamel demineralization in vitro and in vivo in humans

Effects of bioactive substances in milk on mineral and trace element metabolism with special reference to casein phosphopeptides

Bioactivity of phosphopeptides yielded after tryptic hydrolysis of casein (CPP) was reported more than 50 years ago when CPP were found to improve calcium balance in rachitic newborns. Several investigations have been carried out to study the effects of CPP mainly on calcium metabolism but also on other minerals like iron and zinc. Most of the experiments were in vitro studies or short-term experiments like the effects of CPP after single meals or their effect on mineral disappearance from intestinal everted sac or ligated loop. Investigations on calcium balance were also mainly short term, i.e. 3-4 weeks, and mainly done in rats. A few experiments have been carried out in minipigs, an animal model that is closer to the human than the rat. Studies in human were rare and short term. To date a variety of other peptides have been isolated after enzymatic hydrolysis, and some have been investigated for bioactivity, with equivocal findings. Bioactivity of phosphopeptides seemed to be more obvious when investigations were done in vitro or short term. Results were less clear in metabolic balance studies, especially under physiological conditions. The composition of the basal diet, i.e. content of calcium and phytate, or the protein source had a significant impact on the effect of phosphopeptides. It was concluded that phosphopeptides revealed positive effects on mineral solubility and absorbability, and bone mineralisation under certain experimental conditions. Accordingly they could have a beneficial effect on bone health for some groups of the population.

Diet patterns and caries

Few dietary studies have been designed to investigate the effects of intake patterns of food items upon the environment of the teeth. This brief review considers evidence about the effects of choice, combination, and sequence of ingested food and drink upon the pH of human dental plaque in vivo. A series of three studies, which were designed to investigate some of the intra-oral biological events associated with cariogenicity during various eating patterns, are discussed. The principal findings show that if a "meal" includes an item which contains carbohydrate such as sucrose, glucose, or fructose which is rapidly fermented by the acidogenic microorganisms in dental plaque, there will be rapid acid production and the plaque pH will fall. However, other items eaten immediately before, during, or after the consumption of the sugary item can influence the plaque pH. If the non-sugary item stimulates saliva, it will have a pH-raising effect. The remineralizing potential may be enhanced if, for instance, calcium or fluoride is released from the food. However, if one sugary item is followed by another, the demineralizing potential may be enhanced. The results of these experiments are discussed in the context of our current understanding of the dynamics of the carious process. Recent preliminary experiments suggest that other factors, such as the individual subject's speed of consumption, may also affect the cariogenic potential of the oral environment.

Teeth for the future

The main dietary influences on teeth are, with the exception of ingested fluoride, local rather than systemic. The frequent use of carbohydrates which can be rapidly fermented by dental plaque micro-organisms is the major factor in dental decay. Sweetened and/or highly acidic soft drinks or medicines sweetened with sugars may damage the teeth. Similarly infant's comforters also have their dangers if they provide prolonged exposure of the teeth to cariogenic conditions. Although dental caries is primarily a disease of children many adults still develop new lesions and adults who have lost gingival tissue through periodontal disease may develop root surface caries. Pathological conditions of the oral mucosa can arise from nutritional disorders or inappropriate dietary habits. Health education is most effective when it carries a positive message so encouraging patients to eat the right kind of tasty snacks and to round off meals with sugar-free products or a modicum of cheese should in healthier eating without conflicting with general health guidelines.