Does breastfeeding cause cavities?

Every week I get messages and emails from people around the world stressing out because their dentist told them they have to stop breastfeeding because of their child’s tooth decay. People are told that prolonged breastfeeding or breastfeeding overnight increases the risk of having dental caries. Not only does this not make any sense whatsoever (which I’ll explain why below), it is also actually not supported by many different research studies that have been done over the years. Let’s begin with why this whole concept doesn’t even make sense to begin with…

“Long term” breastfeeding causes tooth decay?! NO. Just no.

It makes absolutely no sense whatsoever from a biological, physiological, anthropological, evolutionary perspective that our own breastmilk which our bodies make for our own offspring, would cause cavities. The whole notion of this even being a thing is absolutely ridiculous. There is however, AMPLE evidence that shows breastmilk does not cause cavities. Researchers have actually found that a protein in breastmilk named Lactoferrin, actually kills S. mutans. which is one of the main cavity causing bacterias in our mouths [1,2]. A systematic review on the topic of early childhood carries (ECC) and breastfeeding looked at 139 studies on the topic of breastfeeding and ECC which found that breastfeeding up to the age of 2 years old does NOT increase the risk of ECC [3]. Read again…breastfeeding does NOT increase the risk of cavities!

Credit: Photo by Alan Cooper, University of Adelaide

All you have to do is take a look at the research into our ancestor’s teeth to see that there was very little decay. Mesolithic hunger-gatherers lived on a mostly meat diet with very little carbohydrates and they had MUCH healthier mouths than us! One of the most recent studies stated that almost no cavities or gum disease-associated bacteria was found on our ancestor’s teeth  [4].  The lead author of this study said, “Dental plaque represents the only easily accessible source of preserved human bacteria.” They found that the composition of this bacteria changed with the introduction of farming and again during the Industrial Revolution. We also know that our ancestors breastfed well beyond babyhood. The most well respected researchers in this area suspect the average human child would not have weaned before the age of 2 1/2 and some would have breastfed up to 7 years old [5].

What does this imply? That it is not our milk that has all of a sudden “gone bad” and morphed into a cavity causing liquid…it means our diets full of sugar and our oral hygiene is lacking in many parts of the world (to say the least). Now we eat diets that cause such an acidic, sugary environment we have to clean our teeth twice per day. Our ancestors didn’t brush their teeth…they also didn’t eat sugar or grain. The combination of our sugary diets and questionable oral hygiene however, do. As one of my fellow IBCLC’s Carey Wood stated, “Breastfeeding won’t be magical and help toddlers drinking juice and eating sugary processed foods.” Exactly Carey…exactly! THE ISSUE IS WHAT WE ARE EATING…not our breastmilk. The researchers didn’t find any differences between the two groups until over the age of two years old. Why is this? It’s when we start eating more solid foods! Our toddlers diet increases substantially between 6-24 months old. Unfortunately these toddlers are often eating diets very high in sugar including juice and refined grains.

The study claims that the group of children who ate a “high sugar” diet were more likely to develop cavities if they were breastfeeding, compared to the group who was not breastfeeding (but only over the age of two). The issue here though is not breastmilk in of itself, it is the combination of many different factors working together in the perfect storm to create a more acidic environment for this cavity causing bacteria to grow, mainly; the sugar in their diet, genetics and oral hygiene. The authors also did not include frequency of tooth brushing or dental visits in their analyses! This means that we don’t even know if the kids in the “high sugar” group were brushing their teeth or seeing a dentist! The study also found an association between socioeconomic characteristics and how it was a contributing factor as children in lower income families had more dental cavities. Hhhhmmmm…and breastmilk is still being blamed? Another issue with this group of  “high sugar” kids over the age of 24 months? Only ONE QUARTER of them were still breastfeeding!! How is it that one quarter of the group is representing an entire population of breastfed toddlers? You cannot draw a statistically significant conclusion by defining them as “breastfed” when only one quarter of them were even breastfeeding. This means MOST of these kids in this group they claim to be “breastfeeding” were NOT BREASTFEEDING!

What do other evidence based studies say about tooth decay and breastfeeding?

Some people claim that the lactose in breastmilk could cause tooth decay. Remember that the lactose in our milk is not an isolated component. Our milk is filled with other components that play a role in cavity prevention. Research shows that lactose is protected by the antibacterial and enzymatic qualities of breastmilk [6].  A review in 2013 revealed that there was no conclusive evidence that prolonged breastfeeding increased the risk of early childhood cavities [7]. Breastmilk is not cariogenic (decay causing) [1]. Also, the bacteria that causes cavities and decay is actually contagious and can be passed from adult to child. This is why it’s incredibly important that we as parents focus on our oral health as well. From Dr. Palmer, “Human milk alone does not cause dental caries. Infants exclusively breastfed are not immune to decay due to other factors that impact the infant’s risk for tooth decay. Decay causing bacteria (streptococcus mutans) is transmitted to the infant by way of parents, caregivers, and others” [8]. One study in 2007 that looked at children between the ages of 2-5, concluded that their study provided no evidence to suggest that breastfeeding or its duration are independent risk factors for early childhood caries, severe early childhood caries, or decayed and filled surfaces on primary teeth [9]. All of the research by Dr. Brian Palmer shows how breastfeeding is NOT a cause of decay. Dr. Richard Erickson is another dentist that has done research in this area and comes to the same conclusion.

So what do we know actually DOES cause cavities and is backed up by evidence based research? (As listed by the Australian Breastfeeding Association from their article on this topic. Click here for their full list of references):

• Sugar intake. 
• Strep mutans entering a baby’s mouth. 
• Salivary disorders. 
• Maternal or foetal illness or stress during pregnancy.
• Maternal smoking during pregnancy.
• Poor dietary habits of the family.
• Poor oral and overall hygiene of the family.
• Family genetics — for example the presence of enamel defects.
• Other conditions — for example low birth-weight (including prematurity), malnutrition, asthma, recurrent infections and chronic diseases.

A lot of confusion around this topic has come from the research that looked into bottle feeding overnight. Some people then made the jump that breastfeeding in the night must cause cavities too. How babies feed from a bottle is completely different to how they feed from a breast though. A human nipple is pulled very far back into a baby’s mouth and therefore the breastmilk does not pool near their teeth. An artificial nipple however is NOT pulled far back into the mouth and this can pool where baby’s teeth are, causing decay. This is sometimes referred to as “bottle rot” and it is HIGHLY recommended that you do not put your baby to bed with a bottle.

So what’s the take home message here? There is ample evidence based research that shows breastfeeding does not cause cavities. Knowing what we do about our ancestors (and the fact that they have almost perfect teeth!) it makes absolutely no sense whatsoever that our own species specific breastmilk would all of a sudden cause tooth decay in our modern times. It’s common sense people. Keep on boobin’…do not give your children sugary foods or drinks…practice good oral hygiene…don’t let poorly designed studies and mainstream coverage scare you. The End.

…No.

References:

1. Erickson PR, Mazhari E 1999, Investigation of the role of human breast milk in caries development. Pediatr Dent 21:86–90.
2. Palmer B 1998, The influence of breastfeeding on the development of the oral cavity: a commentary. J Hum Lact14:93–98.
3. Moynihan, P., Tanner, L. M., Holmes, R. D., Hillier-Brown, F., Mashayekhi, A., Kelly, S., & Craig, D 2019, Systematic Review of Evidence Pertaining to Factors That Modify Risk of Early Childhood Caries. JDR clinical and translational research, 4(3), 202–216. https://doi.org/10.1177/2380084418824262
4. Christina J Adler, Keith Dobney, Laura S Weyrich, John Kaidonis, Alan W Walker, Wolfgang Haak, Corey J A Bradshaw, Grant Townsend, Arkadiusz Sołtysiak, Kurt W Alt, Julian Parkhill, Alan Cooper 2013, Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions. Nature Genetics.
5. Dettwyler KA 1994, Breastfeeding Abstracts 14:3-4.
6. Effert FM, Gurner BW. Reaction of human and early milk antibodies with oral streptococci. Infect Immun 1984;44:660-64.
7. Lavigne V 2013, Breastfeeding and Dental Caries: Looking at the Evidence. Clinical Lactation, 4 (1):12-16.
8. Palmer; B. Breastfeeding and infant caries: No connection. ABM News and Views 2000; 6(4):27,31.
9. Iida H, Auinger P, Billings RJ, Weitzman M 2007, Association Between Infant Breastfeeding and Early Childhood Caries in the United States. Pediatrics  120 (4).