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Milk Products in Dental Health: Summary of Evidence

For more than 50 years, many studies have consistently provided evidence for the benefits of milk and milk products on dental health.

Synopsis

Studies to date have demonstrated that milk and milk products such as cheese and yogurt are beneficial to dental and oral health. They play a key role in preventing adverse dental issues such as dental caries and periodontitis. It has also been shown that various bioactive peptides found in milk, as well as calcium, have important functions in the maintenance of dental health through enamel-protective and anticaries effects.

The Evidence

A narrative review paper, published in 2006, indicated that there is substantial evidence for the role of milk products in promoting dental health.¹

Several studies from the US and Europe have associated milk or milk products consumption with lower caries when combined with a normal routine of oral hygiene;
Data from research suggest that cheese has a cariostatic effect by efficiently increasing the concentration of calcium in saliva and plaque;
Studies on milk and periodontal health indicate that a low dietary intake of calcium resulted in more severe periodontal disease, whereas increased calcium and vitamin D intake seemingly yielded protective effects against tooth loss;
There is a large volume of data to suggest that milk and other milk products contain numerous bioactive compounds conducive to preventing caries.

In another review paper, the following data on milk and cheese were provided:²

In human trials, milk has been shown to be essentially “tooth-friendly”, and its consumption does not increase plaque acidity;
There is evidence that the addition of milk, or milk ions calcium and phosphate, to foods diminishes the extent of tooth demineralization and should lead to enhanced remineralization;
Several studies demonstrate that cheese consumption, especially aged cheese, after or before exposure to sugary foods prevents a drop in plaque pH and has enamel-protective effects;
Epidemiological studies indicate that cheese has a protective effect against caries;
Overall, there is evidence to conclude that cheeses have a pronounced anticaries effect.

A recent 2010 cross-sectional study, conducted among 2,058 Japanese children aged 3 years, provided evidence that a high consumption of yogurt, which could include both unsweetened and sweetened yogurt, may be associated with lower prevalence of dental caries in young children.³

Yogurt intake in the highest tertile (≥ 4 times/week) was significantly associated with lower prevalence of caries compared to the lowest tertile (≤ 1 time/week);
There was a clear dose-response relationship;
After adjustment for confounding variables such as toothbrushing frequency, use of fluoride and between-meal snack frequency, adjusted prevalence ratio was 0.78 (95% CI: 0.62-0.98, p_trend = 0.04).

A study published in 2008, which involved 942 Japanese adults aged 40 to 79 years, investigated the relationship between the intake of different milk products and periodontitis. It was concluded that lactic acid foods, such as yogurt and lactic acid drinks, may have a beneficial effect on periodontal disease:⁴

According to multivariate linear regression models, every 10 g per day increment in lactic acid foods was associated with a 0.010 mm decrease in mean probing depth and a 0.014 mm decrease in clinical attachment loss;
Subjects having ≥ 55 g of lactic acid foods per day had a significantly lower prevalence for deep probing depth and severe clinical attachment loss;
After adjustment for confounding variables, the odds ratios for generalized deep probing depth and severe clinical attachment loss were 0.40 (95% CI: 0.23-0.70) and 0.50 (95% CI: 0.29-0.87).

In another study, published in 2006 and conducted among 12,764 US participants aged 18 years or over, it was shown that there was an inverse association between the intake of milk products and prevalence of periodontitis:⁵

Individuals in the highest quintile of intake of milk products were 20% less likely to have periodontitis than those in the lowest quintile, after adjustment for known and suspected periodontitis risk factors such as cigarette smoking, diabetes, dental calculus and gingival bleeding (p = 0.024);
The findings supported the need for adequate intake of milk and milk products as it appears that foods rich in calcium are associated with the prevalence of periodontitis.

Regarding flavoured milk products, such as sugar and fruit juice sweetened milk products, as well as chocolate milk, a 2001 review paper indicated that their cariogenic load is negligible to low and that they are a preferable alternative to similarly sweetened soft drinks.⁶

For more information on chocolate milk, consult the evidence summary Chocolate Milk and Dental Health.

Potential Mechanisms

Caseins, which account for the largest percentage of milk proteins (80%), contain bioactive peptides. They are thought to have a positive effect on cariogenesis via two mechanisms:¹

Prevention of demineralization;
Inhibition of bacterial attachment and/or biofilm formation.

A complex of casein phosphopeptide and amorphous calcium phosphate is formed upon digestion of milk and inhibits dental caries lesions by increasing the level of amorphous calcium phosphate in dental plaque so as to depress enamel demineralization and enhance remineralization.⁷

The adherence of oral bacteria to saliva-coated hydroxylapatite in tooth enamel has been found to be inhibited by three milk-derived compounds, namely casein phosphopeptide, sodium caseinate and glycomacropeptide.⁷

It has been shown that the bovine milk protein, lactoferrin, inhibits the aggregation and adherence of Streptococcus mutans, the main bacteria involved in dental caries, to salivary film.⁸

Some studies have shown that probiotics in milk products reduced S. mutans counts, possibly by modifying the composition of salivary film and preventing bacterial adhesion.⁹

There is evidence to indicate that yogurt consumption decreases the number of salivary mutans streptococci as well as lactobacilli, which are often found in dental plaque.¹⁰

Conclusion

There is consistent scientific evidence that milk and milk products are beneficial to dental health due to the bioactive peptides they contain.

More studies are needed to determine the association between milk products and dental health among children, as well as that between calcium intake and periodontitis.

Further studies are needed to find out whether there is a difference in the benefits provided by unsweetened and sweetened varieties of milk products.

Moreover, additional research on the contribution of probiotics to dental health is also needed.

References

Merritt J et al. Milk helps build strong teeth and promotes oral health. J Calif Dent Assoc 2006;34(5):361-6.
Kashket S et al. Cheese consumption and the development and progression of dental caries. Nutr Rev 2002;60(4):97-103.
Tanaka K et al. Intake of dairy products and the prevalence of dental caries in young children. J Dent 2010;38(7):579-83.
Shimazaki Y et al. Intake of dairy products and periodontal disease: the Hisayama study. J Periodontol 2008;79(1):131-7.
Al-Zahrani MS. Increased intake of dairy products is related to lower periodontitis prevalence. J Periodontol 2006;77(2):289-94.
Levine RS. Milk, flavoured milk products, and caries. Br Dent J 2001;191(1):20.
Aimutis WR. Bioactive properties of milk proteins with particular focus on anticariogenesis. J Nutr 2004;134(4):989S-95S.
Oho T et al. A peptide domain of bovine milk lactoferrin inhibits the interaction between streptococcal surface protein antigen and a salivary agglutinin peptide domain. Infect Immun 2004;72(10):6181-4.
Stamatova I et al. Probiotics: Health benefits in the mouth. Am J Dent 2009;22:329-38.
Petti S et al. A randomized clinical trial of the effect of yogurt on the human salivary microflora. Arch Oral Biol 2001;46(8):705-12.

Keywords: dental health, tooth decay, casein, peptides, bioactive peptides, calcium, flavoured milk, chocolate milk

Scientific Evidence Keywords

Chocolate Milk and Dental Health

Current evidence indicates that, when consumed in moderation, flavoured milk – including chocolate milk – has a low cariogenic potential.
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