Researchers followed over 3,500 families in Shanghai from birth through age 5 to understand how early feeding practices affect children’s tooth decay. They discovered that sugary foods and drinks at 12 months old significantly increased cavity risk, while vitamin D supplements and eating a variety of foods protected teeth. Interestingly, breastfeeding itself didn’t cause cavities. The study suggests that parents can prevent tooth decay by limiting sweets, introducing solid foods at the right time (around 6 months), giving vitamin D supplements, and offering diverse foods—all before children even start school.

The Quick Take

  • What they studied: How different ways of feeding babies in their first two years—like breastfeeding, when to start solid foods, and what foods they eat—affect whether young children develop cavities
  • Who participated: 3,505 families in Shanghai with children ages 3 to 5 years old. Researchers collected information about how parents fed their babies from birth and then checked the children’s teeth for cavities
  • Key finding: Babies who ate sugary foods and sugary drinks at 12 months old were significantly more likely to get cavities. However, babies who got vitamin D supplements regularly and ate many different types of food had fewer cavities. Breastfeeding alone did not cause cavities
  • What it means for you: Parents can help prevent cavities by avoiding sugary snacks and drinks during the first year, starting solid foods around 6 months (not earlier), giving vitamin D supplements, and offering a variety of healthy foods. These simple changes may reduce cavity risk before children turn 3

The Research Details

This was a birth cohort study, which means researchers followed the same group of families over time starting from when babies were born. Parents answered detailed questions about how they fed their babies—including breastfeeding, when they introduced solid foods, and what foods their children ate. When the children were 3 to 5 years old, dentists examined their teeth to count and measure any cavities. The researchers then used statistical methods to find connections between early feeding practices and cavity development.

The study used data from the Shanghai Maternal-Child Pairs Cohort, a well-organized research program designed to track how early life experiences affect children’s health. This type of study is valuable because it follows children forward in time rather than looking backward, which helps researchers understand cause and effect more clearly.

Following children from birth gives researchers a clear picture of what feeding practices actually happened, rather than relying on parents to remember years later. By examining teeth directly instead of just asking about cavities, the researchers got accurate information. This approach helps identify which specific feeding choices matter most for preventing cavities, allowing doctors and parents to focus on the most important changes

This study is fairly reliable because it included a large number of families (3,505), used direct dental examinations rather than just parent reports, and adjusted for other factors that might affect cavities (like parent education and family income). However, the study was conducted only in Shanghai, so results might differ in other countries with different water fluoridation or dietary patterns. Also, parents reported feeding information themselves, which could have some inaccuracies

What the Results Show

The most important finding was about sugar: babies who ate sugary foods in the 24 hours before the 12-month check had about 4% higher cavity risk for each additional sugary food item, and those who drank sugar-sweetened beverages had about 12% higher risk. This means that even small amounts of added sugar during the first year can significantly affect tooth health.

Starting solid foods too early (before 6 months) also increased cavity risk by about 23%. This suggests that babies’ digestive systems and teeth develop better when solid foods are introduced at the recommended time.

On the positive side, babies who consistently received vitamin D supplements from birth to age 2 had lower cavity rates. Additionally, children who ate a variety of different foods at 12 months had fewer cavities. The protective effect of vitamin D was confirmed by survival analysis, which showed that babies getting vitamin D supplements stayed cavity-free longer than those who didn’t.

The study also found that children were more likely to have cavities if their mothers had lower education levels, the family had lower income, mothers smoked during pregnancy, or the primary caregiver had cavities. Children who started brushing teeth late or who ate after brushing their teeth also had more cavities. Sleeping with a bottle was another risk factor. These findings suggest that cavity prevention involves family habits and education, not just what babies eat

This study confirms what many previous studies suggested about sugar and cavities, but it provides stronger evidence because it followed children from birth. Interestingly, it challenges the idea that breastfeeding itself causes cavities—the problem appears to be added sugars, not breast milk. The finding about vitamin D is newer and suggests that nutrition plays a bigger role in cavity prevention than previously emphasized. The importance of dietary diversity aligns with general child nutrition recommendations

The study only included families in Shanghai, so results might not apply to other countries with different diets or water fluoridation. Parents reported their feeding practices from memory, which could be inaccurate. The study couldn’t prove that these feeding practices directly caused cavities—only that they were associated with them. Some families may have dropped out of the study, which could affect results. The study didn’t measure all possible factors that might affect cavities, like how often children brushed their teeth or the exact amount of fluoride exposure

The Bottom Line

Parents should limit sugary foods and drinks during the first year of life (strong evidence). Introduce solid foods around 6 months, not earlier (moderate evidence). Give vitamin D supplements consistently from birth to age 2 (moderate evidence). Offer a variety of different healthy foods starting at 12 months (moderate evidence). Start brushing teeth as soon as they appear and avoid eating after brushing (supporting evidence). These changes appear most important during the first two years when baby teeth are developing

All parents and caregivers of babies should pay attention to these findings, especially those with family histories of cavities or in communities with limited dental care. Healthcare providers should discuss these feeding practices with new parents. Families with lower incomes may benefit most from these simple, low-cost prevention strategies. However, these findings are most relevant to children in similar settings to Shanghai; families in other countries should discuss their specific situation with their pediatrician

Changes in feeding practices should start from birth and continue through age 2, as this is when baby teeth develop and cavity risk is being established. Parents may not see the full benefit until children are 3 to 5 years old when baby teeth are fully developed. However, starting early is important because preventing cavities from forming is easier than treating them later

Want to Apply This Research?

  • Track daily sugar intake for children under 2 years old, specifically counting sugary snacks and sugar-sweetened beverages consumed in a 24-hour period. Set a goal of zero added sugars and monitor weekly trends
  • Use the app to set reminders for vitamin D supplement administration (daily or as prescribed), log the introduction of new foods to track dietary diversity, and record the timing of complementary food introduction to ensure it occurs around 6 months. Create alerts when sugary foods are added to the child’s diet
  • Maintain a long-term feeding log from birth through age 2, tracking breastfeeding duration, complementary feeding start date, vitamin D supplementation consistency, dietary variety score (number of different food groups consumed weekly), and sugar intake frequency. Review monthly patterns to identify areas for improvement and celebrate successes in maintaining healthy feeding practices

This research provides evidence about associations between feeding practices and cavities in young children, but individual results may vary. This information is not a substitute for professional dental or medical advice. Parents should consult with their pediatrician or dentist before making significant changes to their child’s diet or supplementation routine, especially if their child has existing health conditions or is taking other medications. The study was conducted in Shanghai and may not apply equally to all populations. Early cavity prevention is important, but professional dental care and fluoride exposure (as recommended by your dentist) remain essential components of children’s oral health