Researchers tested a special milk formula for toddlers in the Philippines that contained helpful bacteria and a natural fiber. Over 6 months, children who drank this formula developed stronger bones and muscles compared to children who drank regular milk. The formula worked by changing the types of bacteria living in the children’s stomachs in helpful ways. This study suggests that what we feed young children can affect how their bodies grow and develop, especially their bones and muscles. The findings could help doctors and parents make better choices about nutrition for toddlers.

The Quick Take

  • What they studied: Does a special toddler formula with added helpful bacteria and fiber help children develop stronger bones and muscles?
  • Who participated: 182 healthy toddlers aged 2-3 years old living in the Philippines. Half received the special formula, and half received regular milk for 6 months.
  • Key finding: Children drinking the special formula showed stronger bones (measured by bone density) after 3 and 6 months. They also had better muscle strength and more of the helpful bacteria in their stomachs.
  • What it means for you: If you have a toddler, this suggests that choosing a formula with specific helpful bacteria and fiber may support better bone and muscle growth. However, talk to your pediatrician before making changes, as this study was done in one country and more research may be needed.

The Research Details

This was a randomized controlled trial, which is one of the strongest types of research studies. Researchers randomly assigned 182 toddlers into two groups: one group received a special formula containing a helpful bacteria called Limosilactobacillus reuteri and a natural fiber called GOS (galacto-oligosaccharides), while the other group received regular milk. Neither the parents nor the researchers knew which children were in which group until the study ended, which helps prevent bias. The children drank their assigned milk for 6 months, and researchers measured their bone strength, muscle power, and the bacteria in their stomachs at the beginning, 3 months, and 6 months.

The researchers used advanced technology called shotgun metagenomics to identify exactly which bacteria were living in each child’s stomach. They also measured special markers in the blood that show whether bones are getting stronger or weaker. This detailed approach allowed them to understand not just whether the formula worked, but how it worked.

This research design is important because it shows cause and effect, not just connection. By randomly assigning children to groups and keeping the study blinded, researchers could be more confident that the formula itself caused the improvements, not other factors like diet or lifestyle. The use of advanced technology to study gut bacteria helps explain the mechanism—how the formula actually works in the body.

This study has several strengths: it was published in Nature Communications, a highly respected scientific journal; it used a double-blind design to prevent bias; it had a reasonable sample size of 182 children; and it measured multiple outcomes including bone strength, muscle function, and gut bacteria. However, the study was conducted only in the Philippines, so results may not apply equally to all populations. The study lasted 6 months, which is good for seeing short-term effects but doesn’t tell us about long-term benefits.

What the Results Show

Children who drank the special formula showed measurable increases in bone strength (measured by tibia speed of sound, which indicates bone density) after both 3 months and 6 months of drinking the formula. This means their bones were becoming denser and stronger. The children in the special formula group also showed better muscle strength compared to the regular milk group.

The special formula changed the types of bacteria living in the children’s stomachs. Specifically, the helpful bacteria (Limosilactobacillus reuteri) that was added to the formula actually grew and multiplied in the children’s stomachs. Additionally, another type of helpful bacteria called bifidobacteria also increased more in the special formula group. These bacteria changes were directly linked to the improvements in bone quality and muscle strength.

The researchers also found that the formula changed the chemical environment in the children’s stomachs in beneficial ways. They identified 45 different chemical compounds that changed due to the formula, many related to how the body processes certain amino acids. These chemical changes support the growth of healthy bacteria and may help the body absorb nutrients better.

The study measured blood vitamin D levels and bone turnover markers (chemicals that show whether bones are being broken down or built up). While the abstract doesn’t detail all these results, the overall pattern suggests the formula supports better bone health. The children also tolerated the formula well with no major digestive problems reported, suggesting it’s safe for toddlers to consume.

Previous research has shown that helpful bacteria in the gut can affect bone health and muscle development, but most studies were done in animals or adults. This study is important because it demonstrates these effects in young children during a critical growth period. The combination of a specific bacteria (L. reuteri) with a prebiotic fiber (GOS) appears to work better together than either ingredient alone would, which aligns with emerging research on synbiotics (combinations of probiotics and prebiotics).

The study was conducted only in the Philippines with Filipino children, so the results may not apply equally to children from other ethnic backgrounds or living in different environments. The study lasted only 6 months, so we don’t know if the benefits continue longer or if they last after children stop drinking the formula. The study didn’t compare the special formula to other commercial formulas, only to regular milk, so we don’t know if this formula is better than other options available. Additionally, the study included only healthy children, so results may not apply to children with health conditions or nutritional deficiencies.

The Bottom Line

Based on this research, parents of toddlers aged 2-3 years may consider formulas containing L. reuteri and GOS as a potential option to support bone and muscle development. However, this recommendation comes with moderate confidence because the study was done in one population and more research in other groups would strengthen the evidence. Always consult with your pediatrician before changing your child’s formula, especially if your child has any health conditions or allergies.

This research is most relevant to parents of toddlers aged 2-3 years who are still using formula or milk supplements. It may be particularly relevant in areas where children have limited access to diverse foods or where bone health is a concern. Healthcare providers and pediatricians should be aware of this research when making nutrition recommendations. This research is less relevant to children over 3 years old or those eating a varied diet with many whole foods.

Based on this study, improvements in bone strength appeared within 3 months and continued to improve through 6 months. However, you wouldn’t notice these changes yourself—they require medical measurement. Changes in gut bacteria happened within the same timeframe. If you were to try this formula, you’d want to use it consistently for at least 3-6 months to see potential benefits. It’s not a quick fix but rather a long-term nutritional choice.

Want to Apply This Research?

  • Track your toddler’s formula type and daily intake amount. Note any changes in digestion, energy levels, or growth measurements from pediatric checkups. Record dates of any bone density or muscle strength measurements if your doctor performs them.
  • If considering this formula, set a reminder to give it consistently each day. Track which formula you’re using and when you started. Note any digestive changes or tolerance issues. Schedule regular pediatric checkups to monitor growth and development.
  • Maintain a 6-month log of formula consumption and any observable changes in your child’s activity level, growth, or health. Keep records of pediatric measurements including height, weight, and any bone or muscle assessments. Note any digestive tolerance issues. Share this information with your pediatrician at regular checkups to assess whether the formula is meeting your child’s nutritional needs.

This research summary is for educational purposes only and should not replace professional medical advice. Before changing your child’s formula or making any nutritional changes, consult with your pediatrician or registered dietitian. This study was conducted in a specific population (Filipino children) and may not apply equally to all children. Individual results may vary based on genetics, overall diet, health status, and other factors. If your child has allergies, intolerances, or medical conditions, discuss any formula changes with your healthcare provider before proceeding.