Breastfeeding and Tooth Decay – What The Research Says

So you’re breastfeeding, doing everything you can to give your baby a healthy start, and then someone mentions tooth decay—and suddenly, you’re worried. Could something so natural be hurting your baby’s teeth?

Here’s the truth: breastfeeding doesn’t automatically cause tooth decay. But just like anything else in parenting, there are a few things to watch for.

First, What Is Tooth Decay in Babies?

Tooth decay in babies and toddlers is often called early childhood caries (ECC). It’s what happens when a child’s teeth get exposed to sugars (yes, even natural ones like in milk), and bacteria in the mouth turn those sugars into acid. That acid wears away the tooth enamel, leading to cavities.

Cavities aren’t just a minor issue. Baby teeth matter for chewing, speaking, and holding space for adult teeth. So preventing decay early is a big deal—but that doesn’t mean you need to panic about breastfeeding.

Breastfeeding and Tooth Decay: What the Research Really Says

Here’s where it gets a little nuanced:

• Breastfeeding for 12 months. No strong evidence links this with tooth decay. In fact, some studies show that breastfeeding may even help protect against it. There is evidence that breastfeeding up to 12 months is associated with decreased risk of tooth decay. This study emphasizes that sugar intake and oral hygiene matter more than breastfeeding per se.
• Breastfeeding at night? Some studies show a higher risk of cavities when feeding continues frequently through the night after teeth have come in. That’s because saliva production drops when your baby sleeps, and saliva is what helps wash away milk sugars and protect the teeth.

But here’s the key: Breastfeeding alone isn’t the villain. Cavities happen when other factors come into play—like poor brushing habits or a diet high in added sugars.

Is It Possible for Breastfeeding to Cause Tooth Decay?

“It would be evolutionary suicide for breast milk to cause decay…”

– La Leche League

That quote hits the heart of it. Breast milk, on its own, is not a cause of cavities. Human milk has protective factors that actually help fight harmful bacteria. Lab studies show breast milk doesn’t promote decay the same way other sugary liquids (like formula or juice) can.

What Actually Causes Tooth Decay?

• Frequent sugar intake (especially added sugars)
• Bacteria in the mouth (specifically Streptococcus mutans)
• Low saliva production (especially at night)
• Poor oral hygiene (not brushing baby’s teeth)
• Family diet and hygiene habits
• Genetics (like enamel defects)
• Health conditions like prematurity, malnutrition, asthma, and chronic illnesses
• Smoking during pregnancy

Tooth decay isn’t about just one thing—it’s the combination of risk factors over time.

Does Breast Milk Contain Components That Cause Tooth Decay?

No, it doesn’t. Here’s what’s actually in breast milk:

Proteins

• Taurine – supports brain and eye development
• Lactoferrin – protects against bacteria like staph and E. coli

Fats

• Lipase – helps break down fats
• DHA & AA – essential for brain development

Enzymes and Hormones

• Lysozyme – naturally fights bacteria
• Epidermal Growth Factor – helps tissue development

Vitamins and Minerals

• Calcium, phosphorus, iron, and vitamin C (which boosts iron absorption)

Antibodies

• All major types, especially high in colostrum (early milk)

These components reduce the chance of harmful bacteria taking over—not increase it.

How Tooth Decay Actually Starts

Let’s break this down without getting too sciencey:

1. Your baby eats or drinks something with sugar (including breast milk, formula, juice, etc.).
2. Bacteria in the mouth feed on that sugar.
3. The bacteria produce acid.
4. Acid wears away the tooth enamel.
5. Repeated often enough? That’s how cavities form.

This process can happen whether your baby is breastfed, bottle-fed, or both. So it’s not what you feed—it’s also how and when.

What You Can Do To Prevent Tooth Decay

1. Start Oral Care Early

Even before the first tooth pops through, gently wipe your baby’s gums with a soft, clean cloth after feedings—especially at night.

Once teeth come in, brush twice a day using a rice-sized smear of baby toothpaste with a baby toothbrush.

2. If Breastfeeding

If you’re still breastfeeding past a year—especially at night—just be extra mindful of brushing and avoiding sugary snacks or drinks during the day.

3. Watch the Snacking

Frequent snacking, especially on processed carbs or sweetened foods, can make cavities more likely. Milk alone isn’t the main problem—it’s the mix of sugars from other foods plus poor brushing that adds up.

4. Get That First Dental Visit In

The American Academy of Pediatric Dentistry recommends a dental check-up by your baby’s first birthday. That may feel early, but it helps spot any concerns before they become big problems.

Breastfeeding and Tooth Decay Conclusion

Breast milk by itself is the healthiest food for babies’ teeth. It tends to slow bacterial growth and acid production.

However, when breast milk is given with sweetened drinks or foods, the rate of tooth decay can be quicker than with sugar alone.

Breast and cow’s milk contain lactose sugar, which gives food to cavity-causing bacteria when allowed to sit in the mouth, but it doesn’t mean cavities can develop on breast milk alone.

Formula, by contrast, tends to contain multiple sugars—not just lactose—and may pose a higher risk for decay.

Common Questions About Breastfeeding and Tooth Decay

“If breastmilk has natural sugar, doesn’t that mean it causes cavities?”
Breastmilk does contain natural sugar (lactose), but it also has protective elements like antibodies and enzymes. It’s not sugar alone—it’s sugar plus bacteria and time on the teeth that causes cavities.

“Should I stop nursing at night once my baby has teeth?”
Not necessarily. If brushing gets done and there aren’t other risks (like sugary snacks), many kids breastfeed at night and still have healthy teeth. It’s more about the whole picture.

“Is bottle-feeding better for teeth?”
Not if it’s filled with juice, formula, or milk overnight and left in the mouth. That can actually be riskier, especially if the baby falls asleep with a bottle.

Resources

• Find a breastfeeding support group near you.
• Milkology Breastfeeding Class – Affordable, video-based online course to help you master breastfeeding at your own pace.

References

• Tham R., Bowden‑Jones P., Peres M. et al. “Breastfeeding and the risk of dental caries: a systematic review and meta‑analysis.” — Acta Paediatrica (2015)
• Shrestha SK., Tham R., et al. “Association of Breastfeeding and Early Childhood Caries.” — Nutrients (2024)
• Sritangsirikul S., Kitsahawong K., et al. “A longitudinal study on the impact of breastfeeding with or without formula milk on dental caries.” — Scientific Reports (2024)
• UK Government / Public Health England. “Breastfeeding and dental health.” — GOV.UK (2018)
• Australian Breastfeeding Association. “Breastfeeding and Tooth Decay.”
• Erickson KW., Rugh JD. “Investigation of the role of human breast milk in caries development.” — Dental Archives / AAPD (American Academy of Pediatric Dentistry) (date unspecified)
• Tesfay MY., Delbiso TD. “Prevalence of dental caries and its association with breastfeeding duration among young children in Addis Ababa, Ethiopia.” — BMC Public Health (2024)