Author: Brian Palmer, D.D.S.
Breastfeeding and Infant Caries: No Connection
Based on the belief that breastfeeding increases the risk for infant caries, some researchers and healthcare professionals have recommended that infants be weaned with the eruption of the first deciduous tooth. New research, however, indicates that breastfeeding does not increase the risk for infant caries.
In a 1999 review article on breastfeeding and caries, Erickson concluded that “human breastmilk is not cariogenic.” Dr. Erickson’s research has demonstrated that some infant formulas dissolve tooth enamel, significantly reduce pH, and cause dental caries and pulp involvement.1,2 Other authors have also questioned the purported link between breastfeeding and infant caries. A 1998 review by Sinton notes deficiencies in the empiric evidence, citing “the contradictory nature of previous research findings and weak methodology used.”4 Furthermore, the director of the National Institute of Dental and Craniofacial Research, has stated that “population-based studies do not support a definitive link between prolonged breastfeeding and caries.”3
Oulis found that breastfeeding a child for more than 40 days may inhibit the development of nursing caries in children. In support of this finding are several animal and in vitro studies.5 Dreizen found that rats fed rat milk as the sole source of nutrition did not develop caries and those given sucrose-milk solutions developed fewer caries than animals fed sucrose-water solutions.6 In vitro milk has been shown to remineralize artificially demineralized enamel.7 Several components of human milk may also protect against the development of caries. IgA and IgG have the potential to retard streptococcal growth; streptococcus mutans is highly susceptible to the bactericidal action of lactoferrin, a major component of human milk.9,10 Rugg-Gunn reported that cariogenic bacteria may not be able to utilize lactose, the sugar found in breastmilk, as readily as sucrose.8 Confirming the findings of other researchers, this author has evaluated approximately 600 skulls to find little evidence of problems with dental decay among our prehistoric breastfed ancestors.11,12,13,14,15
Factors other than infant feeding may also impact the development of caries. Torney found that maternal bereavement or stress, reduced intake of dairy products, illness, and antibiotic use during pregnancy were associated with increases in infant caries.11
Transmissibility of decay
It is now believed that decay causing bacteria can be transmitted to the infant by way of parents, care-givers, friends, and others. Berkowitz concluded that caries is an infectious and transmissible disease primarily caused by streptococcus mutans.16 Accumulation of this organism to pathogenic levels results from frequent and prolonged exposure to cariogenic substrates. Suhonen found that the later the primary teeth were colonized with streptococcus mutans, the less likely caries were to develop.17
Some assume that because breastmilk contains lactose, it can be as cariogenic as any sugar solution in a bottle. However, lactose is protected by the antibacterial and enzymatic qualities of breastmilk.18 Furthermore, lactase enzyme splits lactose into glucose and galactose in the intestines, rather than in the mouth. There are 4,640 species of mammals, all of whom breastfeed their young. Lactose is present in most of the breastmilk of these species. Humans are but one species of mammals, but are the only species with any significant decay in deciduous teeth. Mammals, starting with the Australopithecines have been on the earth for 2 to 4 million years.19 Modern Homo sapiens have been around for 30,000 to 35,000 years. Dental decay, however, did not become a significant problem until about 8,000 to 10,000 years ago. Anthropologists believe the increase in decay was primarily due to the advent of the cultivated crops. Some anthropologists believe it would be evolutionary suicide for breastmilk to cause decay and that evolution would have selected against it.
Causes of Dental Decay
Empiric evidence has identified several factors that may increase the infant’s risk for caries. To determine why and infant has decay, an in-depth evaluation of the following factors is recommended.
1. Sugar intake is the primary cause of decay. This includes sugar in otherwise nutritious foods such as juices, cereals, breads, raisins, etc. It also applies to sweetened medications. It is very important to understand that it is not the amount of sugar or carbohydrates to which the teeth are exposed, but rather the frequency of exposure that is the key to the development of decay.
2. The timing of introduction and the number of decay causing bacteria that are introduced into the infant’s mouth.
3. Xerostomia or dryness of the mouth (lack of saliva flow).
4. Illnesses of, or stress to, the mother or fetus during development.
5. Poor dietary habits of the family.
6. Poor oral and overall hygiene of the family.
7. Family genetics (minor contributor).
Empiric evidence does not support a causal association between breastfeeding and infant caries. Breastmilk alone, including the lactose in it, does not cause tooth decay. Infants who are exclusively breastfed, however, are not immune to decay as a number of other factors may influence the infant’s risk of caries.
Breastfeeding is critical to the total health and well being of all mammals – both young and old alike throughout the life span. Breastmilk has many proven benefits. Recent studies have documented additional oral and dental benefits including reduced risk of malocclusion, collapsed facial forms, snoring and obstructive sleep apnea.12,20 It is clear that medical and dental communities should begin to educate health insurers and the public about the importance and efficacy of breastfeeding. Breastfeeding truly is the best and cheapest form of health “insurance.”
1. Erickson PR, Mazhare E. Investigation of the role of human breast milk in caries development. Pediatr Dent 1999;21:86-90.
2. Erickson PR, McClintock KL, Green N, et al. J. Estimation of the caries-related risk associated with infant formulas. Pediatr Dent 1998;20:395-403.
3. Slavkin H. Streptococcus Mutans, Early Childhood Caries and New Opportunities. JADA 1999;130:1787-92.
4. Sinton J, Valaitis R, Passarelli C, et al. A systematic overview of the relationship between infant feeding caries and breast-feeding. Ont Dent 1998;75:23-27.
5. Oulis C, Berdouses ED, Vadiakas G, et al. Feeding practices of Greek children with and without nursing caries. Pediatric Dentistry 1999;21:409-16.
6. Dreizen S, Dreizen J, Stone R. The effect on cows milk on dental caries in the rat. J Dent Res 1961;40:1025-28.
7. McDougall W. Effect of milk on enamel demineralization and remineralization in vitro. Caries Res 1977;11:166-72.
8. Rugg-Gunn A., Roberts GJ, Wright WG. Effect of human milk on plaque pH in situ and enamel dissolution in vitro compared with bovine milk, lactose, and sucrose. Caries Res 1985;19:327-34.
9. Arnold R, Cole M., McGhee J. A Bactericidal Effect for Human Lactoferrin. Science 1977;197:263-65.
10. Mandel ID. Caries Prevention: Current Strategies, New Directions. JADA 1996;127:1477-88.
11. Torney PH, Prolonged, On-Demand Breastfeeding and Dental Decay: An Investigation. Unpublished MDS Thesis.1992 Dublin.
12. Palmer B. The Influence of Breastfeeding on the Development of the Oral Cavity: A Commentary. J Hum Lact 1998;14:93-98.
13. Price WA. Nutrition and Physical Degeneration. 6th ed. 1998, New Canaan, Connecticut: Keats Publishing, Inc.
14. Black GV. Operative Dentistry: The Pathology of the Hard Tissues of the Teeth. Second ed. Vol. 1. 1914: Medico-Dental Publishing Co., London: Claudius Ash, Sons & Co., Ltd.
15. Molnar S, Molnar I. Dental Arch Shape and Tooth Wear Variability. Amer J of Phy Anthr 1990;82:385-95.
16. Berkowitz R. Etiology of Nursing Caries: a Microbiologic Perspective. Public Health Dent 1996;56:51-4.
17. Suhonen J, Sener B, Bucher S, et al. Release of Preventive Agents from Pacifiers in Vitro. Schweiz Monatsschr Zahnmed 1994;104:946-51.
18. Effert FM, Gurner BW. Reaction of human and early milk antibodies with oral streptococci. Infect Immun 1984;44:660-64.
19. Crelin E, The Human Vocal Tract: Anatomy, Function, Development and Evolution. 1987, Vantage Press: New York.
20. Palmer B. Breastfeeding: Reducing the risk for obstructive sleep apnea. Breastfeeding Abstracts 1999;18:19-20.
ABM NEWS and VIEWS, The Newsletter of The Academy of Breastfeeding Medicine, 2000, Vol.6, No. 4 (Dec), p27 & 31.
Brian Palmer, D.D.S.