“If breastmilk caused decay – evolution would have selected against it.
It would be evolutionary suicide for breastmilk to cause decay.”
An anthropologist’s view, quoted by the late Dr. Brian Palmer, DDS in Infant Dental Decay: Is it related to Breastfeeding?1
La Leche League GB is often asked about breastfeeding and dental health by mothers who have been told by their dentist that breastfeeding causes tooth decay. Because of their beliefs, some dentists advise early weaning from the breast or at least no night-time nursing. Our leaflet Breastfeeding and Dental Health written for LLL by Harry Torney, BDS (QUB), M DENT SC (TCD) gives referenced studies which show that a breastfed child is significantly less likely to suffer from tooth decay (dental caries) than a child who is artificially fed.2
As well as the continuing benefits to the health of mother 3 and child,4 breastfeeding promotes optimal jaw and tooth development. A breastfed child is less likely to suffer from crooked teeth (malocclusion)5 and the longer the child is breastfed the greater the reduction in risk. A breastfed baby is also less likely to suffer from discolouration of teeth caused by excess fluoride (fluorosis).6
Recent study from University of California
A 2014 study 7 linking breastfeeding past two years to tooth decay may cause mothers concern. Lead author Benjamin Chaffee of the University of California, San Francisco and his team looked at a possible link between longer-term breastfeeding and the risk of tooth decay and cavities, in a survey of 458 babies in low-income families in the city of Porto Alegre, Brazil.
For the study, two trained dentists examined all of the babies when they were about 6, 12 and 38 months old. At six months, the study team gathered data on the number of breast milk bottles the baby drank the day before and any other liquids, such as juice. At the 12-month mark, parents reported whether they fed their babies any of 29 specific foods, including fruits, vegetables, beans, organic meat, candy chips, chocolate milk, cookies, honey, soft drinks or sweet biscuits.
Nearly half of the children had consumed a prepared infant formula drink by age 6 months, the researchers write in the Annals of Epidemiology, but very few still drank formula by age one.
The researchers found that about 40 percent of children breastfed between ages 6 and 24 months had some tooth decay by the end of the study. For babies breastfed for longer than two years and frequently, that number rose to 48 percent. The more frequently a mother breastfed her child beyond the age of 24 months during the day, the greater the child’s risk of severe early tooth decay, researchers found.
“Our study does not suggest that breastfeeding causes caries”
In spite of the results of the study, Benjamin Chaffee is positive about breastfeeding. He said “The No. 1 priority for the breastfeeding mother is to make sure that her child is getting optimal nutrition,” and added “Our study does not suggest that breastfeeding causes caries”.8 The authors speculate that it is possible that breastmilk in conjunction with excess refined sugar in modern foods may be contributing to the greater tooth decay seen in babies breastfed the longest and most often.
Commenting on the 2014 study, William Bowen, professor emeritus in the Center for Oral Biology at the University of Rochester Medical Center in New York said “There are two aspects of breastfeeding – the actual human milk, which has some, but very little, ability to promote tooth decay. The second is the physical aspect of breastfeeding, or even bottle-feeding, and that’s where the problem arrives.”9 Bowen, who was not involved in the 2014 study, said that when a baby sucks on a mother’s breast or from a bottle, the baby’s teeth are sealed off from saliva in the mouth, preventing it from breaking down bacteria, and increasing the chances of tooth decay.
Studies which show human milk may protect against bacteria
The late Dr. Brian Palmer, DDS studied children’s skulls that were thousands of years old and he found almost no cavities.10 One reason may be that the mechanics of breastfeeding make it unlikely for human milk to stay in the baby’s mouth for long. During breastfeeding, the nipple is drawn deep within the baby’s mouth, and milk is literally squirted into the back of it. The nursing child must swallow before he can go on to the next step of the suckling process. In contrast, baby bottles can drip milk, juice, or formula into the baby’s mouth even if he is not actively sucking. If the baby does not swallow, the liquid can pool in the front of the mouth around the teeth. The artificial nipple is very short, so the liquid in the bottle is likely to pass over teeth before being swallowed.
Another reason is that bacteria which cause cavity formations are inhibited by several components of human milk including high pH levels. IgA and IgG have the potential to retard streptococcal growth, and Streptococcus mutans 11 is highly susceptible to the bactericidal action of lactoferrin, an active component of human milk. Human milk also actively strengthens teeth by depositing calcium and phosphorus on them.
Dr. Palmer was of the opinion that dry mouth is another factor that can increase the incidence of early childhood caries. Saliva, which helps maintain normal pH, is not produced as much at night, especially among those who breathe through their mouths. An infant or toddler who nurses often at night continues to produce saliva, which may help combat dry mouth.
Other factors are significantly associated with tooth decay
Dr. Harry Torney found in a survey – Prolonged, on-demand Breastfeeding and Dental Caries – An Investigation 12 – that four factors were significantly associated with the high caries group. The most significant relationship was with defective enamel while the other three factors related to events that had occurred while the child was in utero. One of these was maternal stress and/or bereavement as reported by the mother. Another was a reduced intake of dairy products as estimated retrospectively by the mother. The third factor was medically diagnosed illness in the mother. If a mother’s pre-natal diet and/or antibiotics received during pregnancy have affected the quality of a child’s tooth enamel and resistance to cavities, the permanent teeth are almost always fine. Diet and oral hygiene are also factors.
The effect of diet
The 2014 study concurred with the idea that it is not breastfeeding but diet which may be causing cavities. Our modern diet has many more cavity-inducing foods and it’s often impossible to get all those sugars off a child’s teeth. Streptococcus mutans is an oral bacterium that’s especially hard on tooth enamel in the presence of sugar. Babies can pick up S. mutans from adults who carry the strain and who share food, utensils or mouth kisses with them; therefore, it‘s important that the primary caregiver of a baby also maintains good oral health. It is much more likely to be these factors which cause cavities, making night weaning an irrelevant solution to the problem.
Dental hygiene is important
The authors of the 2014 study are in agreement with Dr. Palmer and Dr. Torney that dental and oral hygiene are also important factors. The Womanly Art of Breastfeeding 13 suggests that the best way to aid dental health is to wipe or brush your child’s teeth thoroughly at least twice a day. It might help to encourage him to swish with, or at least sip, water after eating. Brushing before going to sleep and not offering any carbohydrates after the bedtime teeth cleaning make sense but there is no need to keep your child from nursing at night since human milk by itself actually helps protect against cavities.
Dr. Bowen agrees that it’s very easy to clean an infant’s teeth. A simple wipe in the mouth with a water-dampened cloth or cotton bud can effectively remove food before the baby’s first teeth, he said, adding: “It’s important to get the excess food out of the mouth.” 14
Chaffee, the author of the 2014 study said his team of researchers collected data on tooth brushing habits, but did not investigate a specific link between cleaning teeth after the last feeding and caries. “But anything that removes carbohydrates and sugars from the oral cavity should help prevent tooth decay,” Chaffee said. 15 Some dentists recommend wiping a child’s teeth after each nursing, including during the night, but there is no research to show this difficult procedure is necessary. Some mothers have found Xylitol helpful. This is a natural carbohydrate sugar substitute that interferes with bacteria’s ability to stick to the tooth surface and has been shown to be effective in reducing the caries risk for children of mothers with high levels of S. mutans. A dentist will be able to give further information about this.
While the 2014 study may initially cause concerns among mothers about the effects of longer-term and night time breastfeeding, historically children who nursed all night had little or no decay until the advent of decay-inducing foods. Human milk rarely contributes to decay and actually has tooth-strengthening properties. While parents need to be aware of the dangers of sweet foods and drinks and of the benefits of strict oral hygiene and visits to the dentist, it’s important not to overlook the many health and emotional benefits of breastfeeding for the baby, family and society as a whole. To wean from the breast because of unsubstantiated fears of tooth decay would be denying a baby – and mother – the many benefits from continued breastfeeding and may actually lead to the unnecessary introduction of bottles.
The World Health Organisation 16 recommends that infants be exclusively breastfed for the first six months of life to achieve optimal growth, development and health and then continue breastfeeding for up to two years of age and beyond, alongside complementary foods. When using the evolution of other primates as a comparison point for humans, it is interesting to notice that their breastfeeding would continue for at least two and a half years 17 and anthropologists have found that children naturally wean up to around seven years of age. 18
Written by Anna Burbidge for LLLGB, December 2016
1 Brian Palmer, DDS: “Infant Dental Decay: Is it related to Breastfeeding?” (http://www.brianpalmerdds.com/pdf/caries.pdf)
5 Labbok MH, Hendershot GE: “Does breast-feeding protect against malocclusion? An analysis of the 1981 Child Health Supplement to the National Health Interview Survey”, Am J Prev Med, 1987; Jul-Aug; 3(4):227-32. (http://www.ncbi.nlm.nih.gov/pubmed/3452360)
6 Walton JL, Messer LB: “Dental caries and fluorosis in breast-fed and bottle-fed children”, Caries Res. 1981; 15(2):124-37. (http://www.ncbi.nlm.nih.gov/pubmed/6937260)
7 Benjamin W. Chaffee, DDS, MPH, PhD, Carlos Alberto Feldens, PhD, Márcia Regina Vítolo, PhD: “Association of long-duration breastfeeding and dental caries estimated with marginal structural models”, Annals of Epidemiology, June 2014, Volume 24, Issue 6, Pages 448–454. (http://www.annalsofepidemiology.org/article/S1047-2797(14)00064-7/abstract)
8 “Breastfeeding past two years linked to infant tooth decay”, Reuters Health News, 14 March 2014 (http://www.reuters.com/article/us-breastfeeding-past-two-years-idUSBREA2D1Q820140314)
10 Brian Palmer, DDS: “Infant Dental Decay: Is it related to Breastfeeding?” (http://www.brianpalmerdds.com/pdf/caries.pdf)
11 Slavkin HC: “Streptococcus mutans, early childhood caries and new opportunities”, J Am Dent Assoc. 1999 Dec; 130(12):1787-92. (http://www.ncbi.nlm.nih.gov/pubmed/10599184)
12 Torney, H. “Prolonged, On-Demand Breastfeeding and Dental Caries-An Investigation” [unpublished MDS thesis]. Dublin, Ireland, 1992. See also http://www.lalecheleague.org/nb/nbsepoct02p164.html
13 La Leche League International: “The Womanly Art of Breastfeeding”, 2010 edition: http://www.lllgbbooks.co.uk/store/p91/The_Womanly_Art_of_Breastfeeding.html
14 “Breastfeeding past two years linked to infant tooth decay”, Reuters Health News, 14 March 2014 (http://www.reuters.com/article/us-breastfeeding-past-two-years-idUSBREA2D1Q820140314)
18 Katherine Dettwyler, PhD: “A Natural Age of Weaning” (http://www.whale.to/a/dettwyler.html)