Experts Warn: This Popular Habit Is Linked to Tooth Decay in Toddlers

New Australian research provides stronger evidence against bottle-feeding infants in bed.

Experts are advising parents and carers to avoid using bottles to put toddlers to sleep, following new research that strengthens the link between this habit and early childhood dental cavities and excess weight.

Published in the Australian and New Zealand Journal of Public Health, the study was led by the University of Sydney and drew on data from more than 700 toddlers participating in Western Sydney University’s Healthy Smiles Healthy Kids (HSHK) study—a long-term project tracking children from birth.

Researchers examined survey responses from mothers, along with dental assessments and body measurements of the children. They also accounted for other factors that could affect dental health and body weight.

The authors found that:

• More than 30 percent of children were still bottle-fed to sleep at two years old.
• Children who were bottle-fed to sleep at two years old were almost twice as likely to be overweight in early childhood.
• Children who were bottle-fed to sleep at three years old had nearly twice as many teeth affected by tooth decay in early childhood.

Expert Advice on Bottle Use

University of Sydney lead author, and PhD candidate in the Susan Wakil School of Nursing and Midwifery, Heilok Cheng, said that parents and carers want to do the right thing but may not be aware of the health risks of bottle feeding before naps and at bedtime.

“Australian recommendations advise parents to start introducing cups at 6 months of age and stop using baby bottles at 12 months. Bottle feeding in bed is not recommended at any age. Our research now provides a much more robust evidence base for that advice,” she said.

“Common toddler drinks, including cow’s milk and formula, often contain either natural or added sugars, increasing the risk of tooth decay. When a bottle is offered at bedtime it’s often being used by carers to calm an unsettled child or encourage the child to drift off to sleep. Because the bottle isn’t being offered in response to hunger, it can lead to overfeeding, putting children at risk of unhealthy weight gain.

“We need to do more to support families and help them avoid getting into the habit of putting a child or baby to bed with a bottle, so that our future generations are set up with a healthy future from the start.”

Dental Health Matters Early

The researchers said it was important for parents and carers to understand that dental health was just as crucial for young children who still had baby teeth as for older children and adults, with dental decay in childhood more likely to result in poor dental outcomes later in life.

For further support, Ms. Cheng recommended that parents seek guidance from trusted healthcare professionals and reputable resources to ensure their child’s health and development is on track.

• Children may be eligible for the Child Dental Benefits Scheme, which covers basic dental services like check-ups. The Raising Children’s Network also advises that children should start seeing a dentist by the time they are one year old or when their first tooth comes through, whichever happens first.
• Primary health providers, such as local child and family health nurses or general practitioners, can also monitor children’s growth, development, and milestones, and are best placed to advise on whether a child needs additional or specialist support in relation to growth, overweight and obesity, and dental health.
• Resources on breastfeeding, feeding, toddlers, dental health, and development for supporting parents in the early years are available through organizations like Karitane, Tresillian, and Raising Children’s Network.

Reference: “Bottle feeding to sleep beyond 12 months is associated with higher risk of tooth decay and overweight in Australian children: Findings from the Healthy Smiles Healthy Kids cohort study” by Heilok Cheng, James John, Jane Scott, Elizabeth Denney-Wilson, Loc Do, Sameer Bhole, Louise Baur and Amit Arora, 18 March 2025, Australian and New Zealand Journal of Public Health.
DOI: 10.1016/j.anzjph.2025.100224

The HSHK study is led by Western Sydney University in collaboration with the University of Sydney, Sydney Local Health District, South Western Sydney Local Health District, University of Queensland, University of Technology Sydney, and Curtin University. It is funded by the Australian National Health and Medical Research Council, NSW Health, Australian Dental Research Foundation, and Oral Health Foundation.

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