top of page

Are we all convinced that breast milk causes tooth decay?

Recently, a friend and I were having a conversation and she stated that a baby we knew had cavities and breast milk was the culprit because she was still breastfed at 18 months. She was certain that breast milk or breastfeeding for a prolonged period causes cavities and I was quite confused.

I’ve seen other babies who were breastfed until they were toddlers, but I don’t remember any of them having tooth decay. But now that I think about it, I doubt I ever paid close attention to their teeth. I was puzzled about where this idea even came from.

Is it another attempt at reducing the number of mothers that breastfeed, to increase our reliance on formula? Is this really another case of too much of a good thing, is a bad thing? I mean, its liquid gold and breast is best right?

To be honest, I thought it was on the list of the most absurd things I’ve ever heard! But I thought to myself, let’s do some research and find out before jumping to conclusions.

breastfeeding mom

First and foremost, is it even possible for babies to get tooth decay? Well, yes, children of any age can get cavities and they form faster in baby teeth than in adult teeth. The enamel of baby teeth is also thinner than permanent teeth. Tooth decay, also known as “dental caries,” is quite common in babies.

How are cavities formed? I think this part might not be common knowledge, but cavities are caused by a type of bacteria in the mouth. Babies are born without any of these harmful bacteria, and it seems that studies have proven that parents, (moms more than dads) typically infect their children.

Cavity causing bacteria are transmitted through saliva. The bacteria are called streptococcus mutans and it plays a key role in tooth decay. The bacteria thrive on fermentable carbohydrates and produce an acid that can eat into the enamel of teeth. A 'fermentable carbohydrate' is a carbohydrate that can be broken down into sugars by the bacteria. It includes sugary, starchy, and sticky foods e.g., toffee. There are kids who eat tons of candy and are lucky enough to avoid dental caries because the bacteria play such a key role.

Breastfeeding and cavities

On the positive side, babies tend to drool a lot, especially when teething, and saliva helps to wash away the acid. When sleeping, the flow of saliva slows down which causes the bacteria to have more time to change sugars into acids. So, saliva is your baby’s natural tooth cleaning agent.

Now let’s talk about the risk of developing tooth decay. We know two things are required: bacteria and fermentable carbohydrates.

Does the amount of sugar matter? Well, yes- but here is the thing, the risk of developing cavities is affected less by the total amount of sugar than by the frequency a child consumes it. That doesn’t mean having lots of sugary items every night after a meal won’t affect your little one’s teeth, but it does mean that snacking on sugary items throughout the day is worse than if your child eats the same amount of total sugar in one sitting. By worse, I’m only referring to cavities here, if we were discussing blood sugar, lots of sugar all at once is probably not a good idea.

Does breast milk contain sugar? Yes. Breast milk consists of water, protein, lipids, carbohydrates, vitamins, and minerals. Carbohydrates include sugars, starches, and fiber. There are about 200 different types of sugars in breast milk, but lactose is the main sugar. Breast milk sugar content changes while formula milk doesn’t.

Most infant formulas contain lactose; however, some formulas also contain corn syrup solids, maltodextrin, or sucrose. Streptococcus mutans may not be able to use lactose as easily as sucrose.

What does research say? Well. A lot. Overall, most studies have concluded that breast milk is

not cariogenic (causing tooth decay). The most cited research on this topic comes from two dentists, Dr. Brian Palmer and Dr. Harold Torney who conducted research on human skulls from 500 to 1000 years ago and learnt that cavities were rare in baby teeth, before the era of baby bottles. In this era, babies were breastfed and probably for an extended period.

There have been several other studies that have found no direct link between the two. The March/April 1999 issue of Pediatric Dentistry concluded that human breast milk is not cariogenic. This study utilized extracted teeth to obtain most of its results and studied children only for determining the pH changes in dental plaque (Erickson 1999).

A Finnish study could not find any correlation between caries and breastfeeding among children who were breastfed up to 34 months (Alaluusua 1990). Another review in 2013 by Lavigne “revealed that there was no conclusive evidence that prolonged breastfeeding increased the risk of early childhood cavities.”

Dr. Torney’s research found no correlation between early onset (< 2 years) of dental caries and breastfeeding patterns such as frequent night feeds, feeding to sleep, etc. He concluded that under ordinary circumstances, the antibodies in breast milk destroy the oral bacteria causing decay.


Breast milk contains lactoferrin which has antimicrobial activity and kills Streptococcus mutans. However, the protective effect of breast milk may not be sufficient to counteract the combined effect of the bacteria and the sugars in the milk for children with small defects in the tooth enamel. In these children, weaning may have the opposite effect due to the absence of lactoferrin.

On the other hand, there are studies that suggest mom should be aware of the effects of breastfeeding past 6 months. Another study conducted by Dr Karen Peres on children in Brazil, found that kids who were breastfed for longer than two years were almost 2,5 times more likely to experience cavities than those breastfed for less than one year. It pointed to factors such as difficulty cleaning teeth during nocturnal breastfeeding.

However, the same study identified that the risk for dental caries did not increase when breastfeeding between 12 and 23 months. The study also found an association for socioeconomic characteristics that can contribute to a higher risk of a child having dental caries. Other studies also concluded that children who breastfed for more than 24 months were at a higher risk for tooth decay.

A study by Carrillo-Díaz, Ortega-Martínez et al on the impact of breastfeeding and cosleeping on early childhood caries (ECC) suggests that breastfeeding from 18 months onwards is considered a risk factor for ECC because babies breastfeed frequently at night and the mother is unable to carry out oral cleaning when sleeping, thereby allowing the development of carious lesions.

A study by Erickson in 1999 found that baby teeth immersed in breast milk became stronger. However, the decaying effect was worse in breast milk and sugar than a normal sugar solution. If a baby’s diet contains lots of additional carbohydrates/sugars, they are at a higher risk for developing tooth decay.

Can breastfed babies get tooth decay? Yes.

Is breast milk the direct cause of cavities? I don’t believe it is, breastmilk alone does not appear to be the cause. Traditionally babies who breastfed at night had little to no decay.

The antibodies in breast milk may even counter the bacteria to prevent tooth decay. Breast milk also contains lactoferrin and has a few tooth-strengthening properties.

Habits, diet, and the presence of cavity causing bacteria play a crucial role. Breastfeeding moms may feed on demand, day and night, and while the natural sugars in breast milk can possibly kickstart the process for the cavity causing bacteria, the risk increases when other fermentable carbohydrates are also present.

Studies show that when babies start eating other foods and drinks, some of which are high in sugar, this is what contributes to tooth decay, rather than breastfeeding itself. Which probably explains why we consider prolonged breastfeeding to be an issue.

Good oral hygiene is important especially at night when they produce less saliva. Not cleaning their mouths before bedtime increases the risk of tooth decay in the presence of bacteria and other sugars.

A baby who is exclusively breastfed unless genetically predisposed, will not get dental caries. The baby that has a genetic enamel defect may have greater decay if weaned too soon due to the lack of lactoferrin. Almost all cavities in infants are caused by supplemental foods, sugars, and other substances besides breast milk. Factor in poor oral hygiene and Streptococcus mutans and the risk increase.

Here are 9 tips to avoid tooth decay in breastfed babies:

breastfeeding and tooth decay

  • Avoid sharing utensils or toothbrushes with your baby or toddler, or by letting them stick their fingers in your mouth.

  • Avoid cleaning their pacifier with your own saliva.

  • Avoid using your breast as a pacifier. If your baby falls asleep while breastfeeding it is wise to remove your breast from their mouth.

  • It is also important that you practice good oral hygiene.

  • Limit sugar intake (and frequency) which bacteria need to survive.

  • Clean your baby’s gums even before her first teeth erupt. Wipe them with a damp washcloth or gauze.

  • Start brushing as soon as the first tooth appears. Wet a baby toothbrush and gently rub it back and forth on the surface of the tooth and along the gum line. Try to do this twice a day.

  • Clean your baby’s mouth after medication (especially sweet syrups).

  • Try to reduce the amount of time that sugary substances contact the teeth.



Rated 0 out of 5 stars.
No ratings yet

Add a rating
bottom of page