Breastfeeding after 12 months and dental decay
Continuing to breastfeed after the first few months can bring some challenges. Sadly, one of the biggest struggles can be dealing with the lack of education in wider society. You might imagine that at least parents are safe when talking to those who are medically trained but unfortunately there are no guarantees.
Parents continuing to breastfeed do report that conversations with dentists can be among the most challenging conversations they have with health professionals.
On a surface level, this is perhaps not surprising. This is a group of professionals who come across children suffering with severe dental problems and at the same time, they may have little or no training in breastfeeding and lactation.
Breastmilk enters the body through the mouth. It contains ‘sugars’. You can see how links end up being made: ‘(Breastfeeding) was not even mentioned, not once. We were taught to advise parents to stop all milk at night after the first year to avoid bottle caries.’ (Richa Sharma, a general dental practitioner in the UK).
Our sympathies lie with parents who are often left feeling unsupported and even blamed when they have followed all the international guidance around breastfeeding.
But let’s feel some sympathy for the dentists too. They often receive recommendations that not only contradict each other but contradict what they see in front of them as they work with families who value breastfeeding. There are dentists out there standing up for breastfeeding and advocating for families but doing so without the full support of their colleagues.
A 2019 study wrote,
"Current recommendations by the European Academy of Paediatric Dentistry, American Academy of Paediatric Dentistry, and International Association of Paediatric Dentistry advocate weaning from breast milk and avoiding unrestricted breastfeeding after the eruption of primary teeth in order to lower the risk of early childhood caries (ECC). However, World Health Organization, American Academy of Paediatrics and nutritional recommendations support exclusive breastfeeding up to six months of age, following continued breastfeeding along with appropriate complementary foods, favouring unrestricted and prolonged breastfeeding even beyond the age of two." (Markovic et al, 2019)
Despite some dentistry organisations claiming otherwise, these researchers stated, “Current literature data revealed possible link between breastfeeding and ECC, however without evidence strong enough for the appropriate oral health preventive recommendation to be provided.”
The bottom line is the evidence is not strong enough to suggest a link with continued breastfeeding and early childhood caries, so in the absence of that link, no one should be telling anyone to stop breastfeeding as if there aren’t any other health considerations to take into account. We are looking at a whole child of course but we don't even have a definitive answer when we're just considering teeth. Studies show that breastfeeding helps to prevent malocclusion. Children that breastfeed for longer are less likely to need braces or correction of their bite. So even if we are talking about just the teeth, some studies are saying ‘there may be a link and more evidence is needed’ and other studies are saying, ‘please continue breastfeeding’.
Speaking on behalf of UK government, Public Health England published a statement, updated in 2019, stressing the importance of dentists supporting breastfeeding and providing evidence-based care. They state:
"Breastfeeding is the physiological norm against which other behaviours are compared; therefore, dental teams should promote breastfeeding and include in their advice the risks of not breastfeeding to general and oral health … Since 2001 the WHO has recommended that mothers worldwide exclusively breastfeed infants for the first six months to achieve optimal growth, development and health. Thereafter, they should be given nutritious complementary foods as breastfeeding continues up to the age of two years or beyond. These guidelines were reiterated in the WHO’s Global Strategy (WHO, 2003) and endorsed by the Scientific Advisory Committee on Nutrition (SACN)."
(Public Health England 2019)
The evidence that breastfeeding up to 12 months is protective of dental health is well-established, or to re-word: that not breastfeeding increases risk of dental caries.
Breast milk, unlike formula, contains Lactobacilli, human casein and secretory IgA among other substances, which inhibit the growth of cariogenic bacteria, particularly oral Streptococci, and preventing it sticking to teeth. Lactoferrin, which is a protein found in breastmilk, kills the bacteria responsible for dental decay (Streptococcus mutans).
Once a child is older than 12 months, the message gets more complicated. Some sources state that continuing to breastfeed after 12 months may increase the risk of dental decay. One systematic review by Tham et al. is often cited as making a link between risk of caries and continued breastfeeding (Tham et al. 2015).
Tham et al. is a meta-analysis, meaning they are assessing and studying previous research completed by others to try and find the big picture. They did note a relationship between prolonged breastfeeding and dental decay but they describe problems with the way the data was collected (sometimes retrospective interviews) and the fact that variables were not sufficiently controlled. Unfortunately this message is often lost when professionals talk about Tham at el. Even The Lancet, in their 2016 breastfeeding series, used this study to assert that breastfeeding beyond 12 months increased risk of dental decay and this was the one downside of continuing to breastfeed.
The authors themselves state that:
"Only a few studies included in this review controlled for key confounding factors and this may have resulted in an over‐estimation of the role of prolonged, frequent and nocturnal breastfeeding in the development of dental caries. Until the dietary and oral hygiene details of these children are controlled for, we cannot be certain whether prolonged, frequent or nocturnal breastfeeding can be principally associated with early childhood caries."
(Tham et al. 2015).
Another meta-analysis also noted a relationship between prolonged breastfeeding after 24 months and dental caries but described this as being based on low quality evidence:
"Of the 13,831 papers identified, 627 were screened in duplicate; of these, 139 were included. The highest-level evidence indicated that breastfeeding ≤24 mo does not increase early childhood caries risk but suggested that longer-duration breastfeeding increases risk (low-quality evidence)." (Moynihan et al. 2019).
Another review, published in 2020 concludes that:
"Breastfeeding until the age of one year is not associated with an increased risk of dental caries, and may even provide protection compared with feeding with formula milk. By contrast, infants who are breastfed beyond the age of 12 months demonstrate an increased risk of caries. However, the results derive from heterogeneous studies that do not always take into account contradictory factors such as eating habits of the mother or infant (feeding during the night, number of meals per day, eating sweet foods, etc.), dental hygiene, or the sociocultural context."
(Branger et al. 2019)
A newer study has provided more reassurance for families continuing to breastfeed. Devenish et al. looked at Australian pre-schoolers in 2020. They studied breastfeeding patterns at three months, six months, 12 months and 24 months. They also looked at the intake of free sugars in the diet. The children had a full dental examination between the ages of two and three to assess the caries rate. They concluded:
"Breastfeeding practices were not associated with early childhood caries. Given the wide-ranging benefits of breastfeeding, and the low prevalence of sustained breastfeeding in this study and Australia in general, recommendations to limit breastfeeding are unwarranted, and breastfeeding should be promoted in line with global and national recommendations. To reduce the prevalence of early childhood caries, improved efforts are needed to limit foods high in free sugars."
(Devenish et al. 2020)
It is certainly true that removing other variables in research is a challenge in this area, as is so often the case when looking at infant nutrition and health. We cannot randomly assign some families to breastfeed, others to not. We cannot ask some families to brush teeth and others to not.
The evidence we have does not convince that breastfeeding to 24 months, or beyond, increases risk of dental caries. Even those who are prepared to state that there is a link will comment on the quality of evidence available and call for more research. If someone claims it is an indisputable fact, we need to consider that they may be basing their opinion more on cultural assumptions about prolonged breastfeeding than the science. If we examine human skeletons from the past, where prolonged breastfeeding and night-time breastfeeding is a given, we see very little signs of decay. It is not unlikely that other variables, such as the increase of sugar in the modern diet are more of a concern, ahead of what is the biological norm.
"Breastfeeding in itself does not cause caries. That would defy evolution as cave men did not give their children milk from other animals let alone formula. The issue is the modern western diet whereby we consume very high amounts of sugar. If we restrict sugar intake to a reasonable level (in my opinion and experience that is fruit after meals and very occasional refined sugar products on special occasions) there is no issue with breastfeeding on demand. Offering cows’ milk or formula on demand once baby teeth have erupted is a much greater issue as our teeth are not designed to consume them. In a dental study conducted in Tristan da Cunha, the deterioration of oral health on this remote island community was noted in middle of the 20th century following a change to a diet rich in fermentable carbohydrates. This confirms the role of sugar in the aetiology of dental caries."
(Dentist Richa Sharma)
The bottom line is that even if a convincing powerful study appeared tomorrow, that had removed all the variables and was flawless in its execution, and it showed that breastfeeding beyond 24 months increased risk of dental decay, this does not mean that extended breastfeeding would not happen.
Evidence is beyond dispute that sugars in the diet and fizzy drinks increase risk of tooth decay, and yet adults and children continue to consume these things, because they are making these choices for a multitude of reasons – pleasure, social acceptance, cultural acceptance. The idea that breastfeeding can be ‘switched off’ and stopped because a professional tells you it should be, puts breastfeeding even lower down the list of what is culturally acceptable than fizzy drinks and juice. If a parent says their four-year-old drinks juice or eats biscuits, the chances are the dentist will accept that and explain what else can be done to reduce risk. At most, they may talk about cutting down or offer a sympathetic approach to changing habits. I have yet to hear of a dentist that says, ‘Why is your child eating biscuits? There’s no value in that.’ Does any dentist say, “You need to stop giving your child snacks?” It goes without saying that it is good practice for a health professional to listen to the families they support, and provide information that supports optimum health of a whole child, not just the bits their training focused on.
What can parents do to reduce risk of dental caries? The list may include drinking a water supply that contains fluoride, no smoking in pregnancy, cleaning teeth properly once teeth appear, regular dental check-ups, minimizing exposure to sugar and understanding that some apparently healthy foods (e.g. dried fruit) may increase risk. Regular snacking in the day could also increase risk. Young children should ideally not be offered sugary drinks or juices as normal drinks.
Families can be supported to make all these changes without changing breastfeeding patterns. The danger of having conversations which focus on the breastfeeding patterns, and criticize breastfeeding choices, is that parents are more likely to go underground. They may continue to breastfeed without regular dental visits and be less inclined to trust other messages being given. This is true of so many conversations with health professionals: when breastfeeding is devalued or dismissed, an important relationship is damaged and the future health of families may be at risk.
We are more than our teeth (sorry, dentists). We are social loving connected humans who breastfeed for a thousand reasons. Even if I come back to revise this article months from now, because a new study has demonstrated beyond a shadow of a doubt continuing to breastfeed is a risk factor for ECC, this article will end will an assertion that breastfeeding continues to aid sleep, calm, provides nutrition and immunological protection and reduces the risk of malocclusion. Only a society that values biscuits over breastfeeding would tell families to stop natural-term feeding.
References:
Branger, B., Camelot, F., Droz, D., Houbiers, B. et al. (2019) ‘Breastfeeding and early childhood caries. Review of the literature, recommendations, and prevention.’ Archives de Pédiatrie 26, 8, 497–503.
Devenish, G., Mukhtar, A., Begley, A., Spencer, A.J. et al. (2020) ‘Early childhood feeding practices and dental caries among Australian preschoolers.’ The American Journal of Clinical Nutrition 111, 4, 821–828. doi: 10.1093/ajcn/nqaa012 PMID: 32047898
Marković, Evgenija & Marković, Dejan & Vukovic, Rade & Peric, Tamara & Kilibarda, Biljana & Vukovic, Ana. (2019). Breastfeeding: The perspective of paediatric dentist. Zdravstvena zastita. 48. 35-41. 10.5937/ZZ1904035M.
Moynihan, P., Tanner, L.M., Holmes, R.D., Hillier-Brown, F. et al. (2019) ‘Systematic Review of Evidence Pertaining to Factors That Modify Risk of Early Childhood Caries.’ JDR Clinical & Translational Research 4, 3, 202–216. doi: 10.1177/2380084418824262 PMID: 30931717
Peres KG, Cascaes AM, Nascimento GG, Victora CG. Effect of breastfeeding on malocclusions: a systematic review and meta-analysis. Acta Paediatr. 2015 Dec;104(467):54-61. doi: 10.1111/apa.13103. PMID: 26140303.
Public Health England (2019) Guidance: Breastfeeding and Dental Health. UK: Public Health England. Accessed on11/05/21 at https://www.gov.uk/government/publications/breastfeeding-and-dental-health/breastfeeding-and-dental-health
Tham, R., Bowatte, G., Dharmage, S.C., Tan, D.J. et al. (2015) ‘Breastfeeding and the risk of dental caries: a systematic review and meta-analysis.’ Acta Paediatrica 104, S467, 62–84. doi: https://doi.org/10.1111/apa.13118