Breastfeeding is often considered an effective way to prevent cavities. However, a recent study on mice suggests that breast milk may contribute to tooth decay more than cow’s milk.

Among the three types of milk—breast milk, cow’s milk, and formula—breast milk is less likely to cause cavities than formula but poses a higher risk than cow’s milk, according to Dr. Ruth A. Lawrence from the University of Rochester (USA).

The reason may be that breast milk contains more lactose (a type of milk sugar) than cow’s milk. Meanwhile, cow’s milk has higher levels of calcium and phosphorus, which help prevent the demineralization of tooth enamel.

Tooth decay occurs when cavity-causing bacteria metabolize sugars into acids, damaging the enamel layer that protects teeth. It’s well known that sugary substances like soda, honey, or juice accelerate enamel erosion. The study found that mice fed human milk showed fewer signs of decay than those given sugary drinks but were at higher risk compared to those fed cow’s milk.

Dr. Lawrence highlights that nighttime breastfeeding is a major concern. Experts generally recommend exclusive breastfeeding for the first six months and continued breastfeeding alongside solid foods for at least 12 months. In the first six months, nighttime feeding is not problematic since infants need frequent nutrition and are also teething. However, as babies grow older, the risk increases, particularly for those with a family history of early tooth decay.

Additionally, young children should not fall asleep with a bottle in their mouth, as prolonged exposure to milk sugars can contribute to cavities. Long-term use of pacifiers or bottle nipples can also interfere with saliva production, which is the body’s natural defense against tooth decay.

Mỹ Linh (via Reuters)