Breastfeeding and tooth decay

Tooth decay and dental malformations are something of an epidemic in modern life – just look at the number of dentists and orthodontists that can be found in even a relatively small town. And so I can’t help but ask: where does breastfeeding factor into this? As it turns out, breastfeeding plays quite a large role in a child’s dental health.

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Will breastfeeding at night cause tooth decay?

We all know that we should brush our teeth before bed. But where does this leave the baby or toddler who still breastfeeds during the night? It would be insane to think you can clean his teeth after every feed, so we need to ask a very important question: does breast milk cause tooth decay? The short answer is, no. In fact, breastfeeding children are a lot less prone to tooth decay that bottle-fed children.

Tooth decay in human history

It is fascinating to look at human skulls from hundreds and thousands of years ago. Essentially, you just don’t see tooth decay in babies and young children from those times. Compare that to modern times, where tooth decay is so common it’s almost accepted as the norm. Dr. Brian Palmer is a dentist who studied the skulls of prehistoric and modern humans, and the difference in the prevalence of tooth decay is simply staggering – you can see some of those photos and figures on his website here. Now, to be sure, a lot more has changed in the last few centuries that the introduction of formula and bottles, but since milk is a baby’s the primary food it has to be one of the major factors in tooth decay in babies.

“Nursing caries” – what are they?

You may have heard the term “nursing caries” or “baby bottle caries”. This is a kind of tooth decay that is seen in bottle-fed babies who are put to bed with a bottle. Typically, there is severe decay of the front teeth (sometimes so bad that they rot away completely, or have to be removed) and caries all over the mouth. The confusion, I think, comes from the term “nursing caries”. The word “nursing” may have caused some people to think that breastfeeding is also a cause of this kind of tooth decay, but it is actually quite unique to bottle feeding

Differences between breastfeeding and bottle feeding

We all know that the suckling action at the breast differs very much from how a baby sucks from a bottle, and that a bottle behaves very differently to a breast. This is the key in understanding why night-time bottle feeds contribute to tooth decay while night-time breastfeeding does not.

This is what happens with the bottle: as a baby falls asleep with a bottle in his mouth, the milk continues to drip out of the bottle. Because the baby is not swallowing, the milk pools in the baby’s mouth, and this causes tooth decay. In contrast, the breast doesn’t continue to drip milk unless the baby is actively suckling. Because of the strong suck-swallow reflex, any milk that comes from the breast following a suck is immediately swallowed, so it doesn’t have a chance to pool in the mouth. Breast milk also comes into contact with the teeth a lot less: because babies latch so deeply onto the breast, the milk is actually squirted into the baby’s throat more than into the mouth; and anything that’s in the throat is swallowed immediately.

So we can see that the action of breastfeeding protects a baby from most of the risk factors for nursing caries. But what about breast milk itself?

Does breast milk cause tooth decay?

Tooth decay is not actually caused by any food – well, not directly. It is caused by a bacteria called Streptococcus mutans (I’ll call it SM for short). So where does sugar come in, you ask? As it turns out, carbohydrate – sugar – is SM’s favourite food. As the sugar is digested and fermented by SM, it produces a lot of acids, and it’s these acids that end up eating your tooth enamel and causing tooth decay.

Breast milk contains lactose, which is a type of sugar unique to mammalian milk (yes, formula also contains lactose, and usually a few other carbs as well). SM can ferment lactose into acids, but it’s not its favourite food – you get a lot less acid from lactose than from other carbohydrates. What is interesting, though, is that if you place SM in breast milk, it produces little to no acid. This is thought to be because of breast milk’s antibacterial properties. Specifically, breast milk contains a protein called lactoferrin, which has an anti-bacterial action – and SM is especially vulnerable to lactoferrin. It is also thought that the minerals in breast milk bind to whatever acids are produced, which neutralizes them.

So it is clear that breast milk by itself does not promote tooth decay. But this doesn’t mean that breast milk renders a baby immune to tooth decay. The moment you add in other carbohydrates or sugars; tooth decay can develop very quickly. The take-home lesson is this: if your baby is eating or drinking anything other than breast milk, you need to clean his teeth very well before bed to remove all traces of carbohydrates, and then only breastfeed during the night with no other foods or drinks.

Breastfeeding and jaw development

One aspect of breastfeeding that is often overlooked is the effect it has on the development of the jaw and facial structures. Briefly, breastfeeding allows the jaw and face to develop as it normally should, with a broad palate and all the teeth in their proper places. In contrast, sucking on artificial teats can cause an infant to develop a narrow, high palate and crooked teeth. This may not seem like such a big deal, but it turns out to be more important than you think. (I’m again indebted to Dr. Brian Palmer for this interesting piece of information). When a person has a high palate (such as can be formed by bottle feeding), it obstructs the nasal passages – basically, the bones of the hard palate stick up into the floor of the nose, which makes the nasal passages narrower. Narrower nasal passages mean that it’s more difficult to breathe through the nose, especially while sleeping; so you tend to breathe through your mouth more. Mouth breathing causes the inside of the mouth to dry out – and this creates an ideal environment for tooth decay.

Beyond breastfeeding

I hope this information has laid to rest any fears you may have had that night-time breastfeeding will cause your child’s teeth to rot out. But please remember, there’s a lot more to dental health than just breastfeeding. Breastfeeding doesn’t make a child immune to tooth decay any more than bottle-feeding guarantees it; it is just one way of stacking the odds in your favour. Good dental hygiene and avoiding frequent exposure to refined carbohydrates and sugar remain vital in protecting your little one’s teeth.

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