Dental Caries and Infant Feeding
by Anne Eglash MD, IBCLC, FABM
According to the authors of this week’s CQW, 60-90% of school-aged children globally sustain dental decay. Early childhood caries (ECC) are defined as cavities in the primary teeth of children under the age of 6. Early childhood caries, according to the American Dental Association, have often be attributed inappropriate feeding practices, such as bottle feeding during the night, or toddler breastfeeding frequently throughout the night. The evidence on the association between type of infant feeding and ECC is mixed, and there is not a consistent association found.
There are other factors that appear to play a role in ECC, including the mother’s vitamin D status during pregnancy, and the presence of cariogenic bacteria, particular mutans streptococci, in the mouths of mother and infant.
The authors of this study were interested in whether formula or breastmilk have a direct impact on dental enamel quality. They designed a study to compare the effects of breastmilk, plain infant formula, and infant formula with probiotics, by immersing the teeth in the fluids, and measuring any effect on enamel. They used 36 spanking clean and healthy primary teeth shed or extracted from children. Each tooth was first suspended in a bacterial broth containing strep mutans. Then 12 were immersed in breastmilk, 12 in plain infant formula, and 12 in probiotic-containing infant formula. They soaked the teeth for a week, then measured their enamel quality by measuring calcium and phosphorus % weight.
- The teeth soaked in breastmilk had an increase in % phosphorus.
- The teeth soaked in breastmilk had an increase in % calcium.
- The teeth soaked in either type of formula didn’t change their % calcium.
- The teeth soaked in the probiotic formula gained calcium whereas the plain formula did not. Therefore, the probiotics made a difference.
- The teeth soaked in either type of formula lost calcium.
- All 3 categories of teeth lost phosphorus, except the loss was insignificant for teeth soaked in breastmilk.
See the Answer
This study quantitatively investigated the changes in enamel mineral content of primary teeth after immersion in human breast milk and plain and probiotic-containing infant formulas.
Thirty-six sound primary anterior teeth were collected and assessed for mineral content (calcium and phosphorus content in wt%) using scanning electron microscope attached with energy-dispersive X-ray analyser (SEM–EDXA). In order to create a microbial-induced caries model, the enamel surfaces of the teeth were inoculated with mutans streptococci and then each tooth was randomly assigned to one of three groups: human breast milk, plain infant formula or probiotic-containing infant formula (n = 12) each. Teeth were then soaked in the designated type of milk, and the solutions were replenished every day for 1 week after which the mineral content was measured again using SEM–EDXA. Wilcoxon signed-rank test was used to study the changes by time within each group, and the significance level was set at P ≤ 0.05.
Treatment of enamel surface with breast milk has significantly increased mean Ca wt%, while no significant changes were detected in mean P wt%. On the other hand, when primary teeth were soaked in plain or probiotic-containing infant formulas, both mean values of both Ca and P wt% significantly decreased.
In conclusion, whereas breast milk might confer some protective effect against enamel demineralisation, infant formulas whether plain or supplemented with some probiotics might promote loss of minerals from enamel surface.
The teeth soaked in breastmilk gained a significant amount of calcium and lost an insignificant amount of phosphorus. The teeth soaked in both formulas lost a significant amount of calcium and phosphorus.
The authors believe this occurred because the formula had more carbohydrates than breastmilk, and also a lower pH, meaning they were more acidic. Acidity weakens enamel. Studies have shown that adding fluoride to formula in low doses helps to prevent the cariogenicity of formula due to these factors. It is possible that the formulas used in this study did not contain fluoride.
Little is known about how the bioactive factors in breastmilk may have played a role in increasing the calcium % in the enamel. Many bioactive factors are anti-bacterial, affected the activity of Strep mutans on the teeth.
Another interesting finding in this study is that the formula with probiotics caused more loss of calcium and phosphorus than the plain formula. The researchers cite studies demonstrating that other bacteria in the mouth besides Strep mutans can contribute to dental cavities by creating an acid environment. An example would be the probiotic bacteria used to make yogurt. The bacteria, when exposed to lactose in the milk, create acids such as lactic acid.