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ARTICLE: William H. Bowen and Ruth A. Lawrence Comparison of the Cariogenicity of Cola, Honey, Cow Milk, Human Milk, and Sucrose Pediatrics 2005; 116: 921-926 [Abstract] [Full text] [PDF]

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Kids, cows and caries: I smell a rat

Alison Barrett   (7 October 2005)

Kids, cows and caries: I smell a rat 7 October 2005
Alison Barrett, MD, Clinical Director, Maternity Services Waikato Hospital, New Zealand Send letter to journal: Re: Kids, cows and caries: I smell a rat barretta{at}waikatodhb.govt.nz Alison Barrett	There is no evidence in “Comparison of the Cariogenicity of Cola, Honey, Cow Milk, Human Milk, and Sucrose” that “human milk clearly has some potential to promote caries development”, only that caries development is possible when months-old frozen human milk is applied to the teeth of desalivated laboratory rats. The relevance of this finding for human infants is uncertain given that fresh human milk – combined with human saliva – offers many antibacterial properties, including specific protection against streptococcus mutans(1). However, freezing human milk can neutralize some of its beneficial properties(2,3,4). The authors point to human milk’s high lactose content and suggest that this partially explains their findings because “aqueous solutions of lactose are modestly cariogenic”. Yet it is also reasonable to conclude that neutralizing some of human milk’s beneficial properties through freezing, and applying it with an artificial feeding system can turn it into something resembling an aqueous lactose solution. The authors’ conclusion that “allowing an infant to sleep on the nipple should be discouraged” is similarly unfounded because it implies in vivo application of breast milk to infant teeth, which has not been demonstrated. In this way the authors discount the significance of reciprocal fitness, the ability of the human breast to participate in many aspects of infectious disease prevention(5,6). This may include protection against dental caries. In contrast, studies have demonstrated that nighttime feeding and allowing the baby to sleep at the breast increase breastfeeding duration and exclusivity (7,8,9). Moreover, in traditional societies practicing long-term nighttime breastfeeding, the incidence of dental caries is extremely low while rates of lactational amenorrhea and access to breastfeeding’s numerous other benefits are very high. The authors rightly point out that in Western culture at least “those most affected [with early childhood caries] are usually economically and socially deprived and carry additional burdens of ill health”. Yet, these are the very same groups with the lowest breastfeeding rates, and their ill-health burden – possibly including their increased rate of caries – is surely related. Based on the evidence presented, about the only inference the authors can make with any certainty is that rats are better off drinking fresh cow milk in preference to stale human milk. Given the way the media have been reporting its erroneous conclusions(10,11,12), the negative impact this flawed article is having on public awareness is deeply worrying. References 1. Camling E, Gahnberg L, Krasse, B.The relationship between IgA antibodies to Streptococcus mutans antigens in human saliva and breast milk and the numbers of indigenous oral Streptococcus mutans. Arch Oral Biol. 1987; 32(1):21-5. 2. Hanna N, Ahmed K, Anwar M, Petrova A, Hiatt M, Hegyi T. Effect of storage on breast milk antioxidant activity. Arch Dis Child Fetal Neonatal Ed. 2004 Nov;89(6):F518-20. 3. Hernandez J, Lemons P, Lemons J, Todd J. Effect of storage processes on the bacterial growth-inhibiting activity of human breast milk. Pediatrics. 1979 Apr; 63(4):597-601. 4. Ogundele, M. Techniques for the storage of human breast milk: implications for anti-microbial functions and safety of stored milk. European Journal of Pediatrics. 2000 159 (11) 793-798. 5. Riordan J. The Biological Specificity of Breastmilk. Chapter 6 in: Riordan J. (ed.) Breastfeeding and Human Lactation Jones and Bartlett Publishers, Sudbury Massachusetts pp 97-135. 6. Newman, J. How Breast Milk Protects Newborns. Scientific American 1995;273:76-9 7. Quandt SA. Biological and behavioral predictors of exclusive breastfeeding duration. Med Anthropol. 1985 Spring;9(2):139-51. 8. Butler S, Williams M, Tukuitonga C, Paterson J. Factors associated with not breastfeeding exclusively among mothers of a cohort of Pacific infants in New Zealand. N Z Med J. 2004 Jun 4;117(1195):U908. 9. Ball HL. Breastfeeding, bed-sharing, and infant sleep. Birth. 2003 Sep;30(3):181-8. 10. Reuters UK, 4 October 2005. Breastfeeding shows cavity-causing potential. http://today.reuters.co.uk/news/newsArticle.aspx?type=healthNews&storyID=2005 -10-04T184117Z_01_MUN464214_RTRIDST_0_HEALTH-BREAST-MILK- DC.XML&archived=False 11. Channel 3000, WISCTV.COM. Cow Milk Beats Breast Milk For Healthy Teeth, Study Says. http://www.channel3000.com/health/5051349/detail.html 12. All Headline News, 4 October 2005. Breast Milk Not as Beneficial to Baby Teeth as Cow Milk. http://www.allheadlinenews.com/articles/7000376532 Conflict of Interest: None declared