Most of us know of the many health and economic reasons to breastfeed for mothers and babies. We are told regularly that “breast is best,” and although there continues to be debate about the degree that not breastfeeding results in health problems for an individual dyad in a Western society, we acknowledge that whether one does it or not, breastfeeding is definitely a healthy choice. However, most mothers who continue to breastfeed beyond a year, especially those who continue to nurse at night, face backlash from an unexpected source: the dentist.

Many families face a dentist who is adamant that they give up breastfeeding or give up night feeds due to the higher risk of cavities despite the other benefits to the families that breastfeeding may confer. What are parents to do? Give up breastfeeding or accept the risk? Or can families have their breast milk and drink it too?

Before we get to what parents should consider, we have to first look at what the research is really telling us. Does the research support the idea that longer breastfeeding is associated with the risk of cavities? Or, like many breastfeeding advocates insist, the dentists have it all wrong? 

Most recently, research that made a lot of headlines reported a strong relationship between breastfeeding duration and the emergence of cavities in young children. The study was inclusive in looking at other feeding habits as the child aged (to control for other sugar intake), frequency of breastfeeding, and child growth. Despite controlling for these other variables using the appropriate statistics, they found that that both breastfeeding beyond two years was associated with greater risk for cavities and that this relationship was moderated by frequency of breastfeeding (with greater frequency and long-term breastfeeding showing the highest risk and prevalence of cavities).

How does this fit with other research? Well, it both supports and contradicts it. For example, a report using survey data put out by La Leche League International found that there was a relationship between breastfeeding length and cavities; however, a recent research review found no evidence to suggest that breastfeeding causes cavities. Confused much? Don’t worry, you’re not alone.

The problem is seems is that both sides are right. Breastfeeding is both linked to a higher risk of developing cavities and does not cause them. (No, that’s not a typo and I have not gone senile.) Add to this, it is not just a confound of child’s diet being higher in sugar or anything like that, supporting that recent study that controlled for those variables.

To understand this weird relationship, we first need to understand what causes cavities. For years we were all told sugar would rot our teeth. I know I grew up completely believing that half-fallacy and was furious when my brother could eat all the sugar he wanted while rarely brushing and developed zero cavities whereas I had a mouth riddled with them despite my mother forcing my brushing like a tyrant. Turns out it’s not the sugar that rots our teeth but certain bacteria such as Streptococcus sobrinus and Streptococcus mutans that feed on sugar and excrete an acid that wears away the enamel and increases plaque pH, eventually causing cavities.

Although the same process occurs in every person’s mouth, the number of bacteria every person has varies. This means that two people with the identical diet can have vastly different dental health simply due to the prevalence of these bacteria. (This would be why my brother never suffered a cavity and me tons -- his levels of the bacteria were nearly nonexistent whereas mine were through the roof.)

We know that this bacteria feeds on sugar. We also know sugar is in breast milk (as lactose) so it makes sense to think of a causal relation, so why do I say no? Well, first off, research looking at the cariogenic effect of breast milk on enamel decalcification, plaque pH, and cavities found that breast milk per se was not cariogenic. How is this? Well, it’s believed to be the antibacterial properties of breast milk, particularly lactoferrin, that inhibit the bacteria from using the lactose in breast milk to wreck havoc in our mouths.

So we have the answer to why breast milk does not cause cavities, but why then is there a link? The same study that found that breast milk per se was not cariogenic also found that the addition of a small amount of sucrose to breast milk led to the development of cavities in just over three weeks. This mixture was actually more cariogenic than cow’s milk and, even more shockingly, more cariogenic than a sucrose solution.

What does this mean? It means the problem with breastfeeding regarding cavities is not the breastfeeding but the mixture of breast milk with sugary foods or drinks in the mouth (as a result of improper or lack of brushing and/or failure to rinse the mouth with water regularly). If children are not brushing their teeth properly enough, and sugar particles are remaining in the mouth and mixing with breast milk, the effect is worse on the teeth than the child drinking sugar water regularly without breast milk.

What are parents to do? The idea of just quitting breastfeeding or weaning at night doesn’t hold a lot of water, in my opinion. Mothers continue to nurse because it works for them and their children for myriad reasons (including easing teething pain, comfort nursing during separation anxiety, helping a child fall asleep again between sleep cycles, etc.). Regarding night nursing, the reality for many families is that many healthy, typically-developing, and happy children still wake regularly at age 3 and breastfeeding is associated with these wakings.   

Instead of ceasing breastfeeding, here are a few ideas that can help to reduce the risk of cavities in longer-term breastfeeding children:

  1. Brush, brush, brush. Clearly the research demonstrates that brushing thoroughly accompanied by flossing is absolutely the best thing you can do for your child. Remove all food particles from the mouth and there is nothing for breast milk to interact with to cause cavities.
  2. Water rules. Drinking predominately water throughout the day not only doesn’t add any sugars (unlike juices and cow’s milk which are filled with sugar), but actually works to dislodge any food that is stuck between the teeth, helping to keep the mouth clear of foods that may feed the bacteria that causes cavities (with or without breast milk). Most families end up with children whose liquid diet is a mix breast milk with both cow’s milk and juice and both of these are cariogenic, so switching to predominantly water is a great step to reducing the risk of cavities all around.
  3. Use xylitol (this applies to both mom and baby). Xylitol is, oddly, a sweetener that is found in many fruits and vegetables that has been found to not only be non-cariogenic but also to have some inhibitory effect on the development of cavities (i.e., it is cariostatic). As the passing of the bacteria that causes cavities is moderately related to maternal-child saliva transmission, the use of a xylitol-based chewing gum has been found to reduce cavities in children at age 5, more so than the usual fluoride treatments. In children, xylitol chewing gum has also been associated with long-term reduction of new cavities in high-risk children. Although most of the research is focused on the chewing gum, many children’s toothpastes are now including xylitol as the sweetener, and so if chewing gum isn’t the habit you want, look for a toothpaste with xylitol. If your child is old enough and chews gum, look for a xylitol-based chewing gum.

So long as breastfeeding continues to work for you and your child, fear of cavities need not stop you (and feel free to tell your dentist as much!). Yes, you may need to take proactive steps to ensure breast milk doesn’t interact with sugary foods, but there are several ways to do this, all of which are better than weaning if you don’t want to. Happy breastfeeding!

 

Images via Finizio/Flickr; makelessnoise/Flickr