December 2009

“Functional Foods” are foods or dietary components that have a beneficial effect on one or more target functions in the body beyond basic nutrition. The concept was developed in Japan in the 1980s where the Ministry of Health and Welfare saw the potential to use food as a vehicle to address the nation’s spiralling health care costs. They introduced a regulatory system to approve certain foods with documented health benefits in the hope of improving the health of the nation’s aging population. Although the terminology is relatively recent, the concept of “Functional Foods” is well embedded amongst those interested in oral health; a classic example being the adjustment of fluoride in water to benefit oral health, an initiative which preceded the concept of functional foods by 40 years. In the rapidly growing area of functional foods research, health promoting food components have been derived from mineral, animal and plant sources to tackle oral diseases such as caries, periodontal disease and oral cancer The use of minerals includes the caries preventive benefit of fluoride which has been exploited by adding it to water, salt, milk and sugar (the latter on an experimental basis). Other minerals are calcium and phosphate which are major components of enamel and dentine and have been incorporated in sugar free chewing gum in various forms to try and increase enamel remineralisation. The cariostatic effects of animal products, e.g. milk and cheese have been reported in a variety of studies over the last 25 years. Postulated mechanisms of action include salivary stimulation, reduction of bacterial adhesion, reduction of enamel demineralisation, and/or promotion of remineralisation by casein and ionisable Ca and P. The cariostatic properties of cheese may result from a combination of the effects described in addition to the action of biologically active peptides in the protein fraction and/or naturally occurring probiotics. Development of technology to isolate some of the many peptides in cheese has opened the door to future research which will determine their bioactivity in the mouth. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes, derived from bovine milk protein, casein, calcium and phosphate is the subject of ongoing research in the prevention of dental caries. Identification and isolation of the components of dairy products which protect against dental caries could lead to an enhancement of the oral health benefits and functionality of dairy products or other products to which these components were added. The word probiotic is a relatively new word meaning “for life” and it is currently used to describe bacteria associated with beneficial effects for humans and animals. Probiotics have been defined as “live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host.” (FAO, WHO, 2001). A small number of probiotics with potential for reducing caries risk by decreasing the level of S. mutans in the mouth have been identified and it is likely that this number will increase in the future as our knowledge and understanding of this area continues to improve. Probiotics may not replace conventional caries preventive approaches but the incorporation of strains with even slight oral health benefits in commonly consumed foods such as dairy products may provide a useful improvement in oral health at the population level. Further well conducted randomised controlled human trials will be needed to test the efficacy of existing and new probiotics in controlling dental caries. The use of probiotics to prevent or control oral disease looks like a promising area for future development. In addition to mineral and animal products, plant products have shown great promise in the fight against caries. As sugar is the food most commonly associated with caries, sugar substitutes, many of which are derived from plants are commonly associated with caries prevention. The replacement of fermentable non milk extrinsic sugars by sugar alcohols or artificial sweeteners make confectionary safer for teeth as they carry a reduced risk of dental caries. Polyphenols are phytochemicals that are found in food substances produced from plants such as fruits, vegetables, cereals, olive, dry legumes, chocolate and beverages, such as tea, coffee and wine. They are active against a wide spectrum of microbes. Polyphenols are found in many different commonly-consumed foods and beverages, for example tea, cranberries, coco and grapes. Their activity against bacteria including S. mutans and biofilm has been studied; the positive results indicate a need for further carefully controlled studies Compared to research on foods with caries protective properties, there has been little progress in the development of foods with specific periodontal benefits. Cross sectional studies indicate the need for further research on vitamins such as 25-hydroxyvitamin D (3) and Folic acid (a B-complex vitamin) in the promotion of periodontal health. Reported associations between increased intake of dairy products and a lower prevalence of periodontal disease also warrant further investigation. The use of probiotics in food for periodontal health is another area ripe for future research. Cranberry juice and tea are two plant products which have been studied for their effect on inhibiting microbial adhesion to hard and soft tissues. Inhibition of co-aggregation among oral bacteria may disturb the development and maturation of dental plaque and could, therefore, potentially improve plaque control. Again further research is needed.