Researchers in the Czech Republic studied 95 families—some eating only plants, some eating plants plus dairy/eggs, and some eating meat—to see how different diets affected children’s health. They looked at 142 kids and 187 adults, checking their growth, heart health, bones, and nutrient levels through blood tests and food records. The good news: kids on plant-based diets grew normally and had healthier cholesterol levels than meat-eating kids. The concern: vegan kids had lower iodine levels, which is important for brain development. Overall, plant-based diets worked well for kids, but families need to pay attention to getting enough iodine.

The Quick Take

  • What they studied: Whether children and adults eating only plants, plants plus dairy/eggs, or meat-based diets had different growth, heart health, bone strength, and nutrient levels.
  • Who participated: 142 children and 187 adults from 95 Czech families. About half the families were vegan (eating no animal products), a quarter were vegetarian (eating dairy and eggs but no meat), and a quarter ate meat. All the vegan and vegetarian children had been eating that way since birth.
  • Key finding: Vegan and vegetarian children grew just as well as meat-eating children and actually had better cholesterol and heart health numbers. However, vegan children had lower iodine levels in their urine, though their thyroid function was still normal.
  • What it means for you: If your family is considering a plant-based diet for your children, this research suggests it can support normal growth and may even improve heart health. However, you should make sure to include iodine-rich plant foods (like seaweed, iodized salt, or fortified products) or consider an iodine supplement. Talk to your doctor before making major dietary changes for your child.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of different families and compared them. They didn’t follow families over years; instead, they collected information all at once. The researchers measured three groups: vegan families (no animal products at all), vegetarian families (dairy and eggs allowed), and omnivorous families (eating meat). They collected detailed information about what each person ate over three days, took blood and urine samples, and did physical measurements like height and weight. They used statistical methods that account for the fact that family members are related and share similar genetics and home environments.

This approach is important because it lets researchers compare real families living their actual diets, rather than asking people to change their eating habits for a study. By including families where children had been on the same diet since birth, the researchers could see long-term effects. The fact that they measured both blood and urine samples, plus physical growth, gives a complete picture of health. Using statistical methods that account for family relationships is important because parents and children naturally share similar nutrient levels due to genetics and shared meals.

This study has several strengths: it included actual families living these diets long-term, it measured multiple health markers (not just one), and it used careful statistical methods. However, it’s a snapshot study, not a long-term follow-up, so we can’t be completely sure about cause and effect. The sample size is moderate (142 children), which is reasonable but not huge. The study was done in the Czech Republic, so results might be slightly different in other countries with different food availability. The researchers adjusted their analysis for factors that could affect results, like age and socioeconomic status.

What the Results Show

Children in all three diet groups had similar heights and weights, meaning plant-based diets supported normal growth just as well as meat-eating diets. This is reassuring for parents worried that vegan or vegetarian diets might stunt children’s growth. Vegan and vegetarian children actually had better cholesterol numbers than meat-eating children—their LDL cholesterol (the ‘bad’ kind) and total cholesterol were lower. This suggests that plant-based diets may be better for heart health, even in childhood. Bone turnover markers (which show how actively bones are being rebuilt) were similar across all groups, suggesting bone health was comparable. Vitamin D levels were actually highest in the vegan group, which was unexpected and positive.

The most notable secondary finding was that vegan children had lower iodine levels in their urine compared to other groups. Iodine is important for thyroid function and brain development. However, when researchers checked thyroid-stimulating hormone (TSH) levels—a blood test that shows if the thyroid is working properly—there were no differences between groups. This suggests that even with lower iodine, the vegan children’s thyroids were still functioning normally, at least at the time of testing. The study also found that certain nutrients and vitamins (like B12, vitamin D, selenium, and zinc) showed family clustering, meaning parents and children had similar levels, likely due to shared genetics and eating patterns.

Previous research has raised concerns about nutrient deficiencies in vegan children, particularly regarding iodine, vitamin B12, iron, and calcium. This study confirms that iodine intake may be lower in vegan families, which aligns with earlier findings. However, it adds important new information: despite lower iodine levels, thyroid function remained normal in vegan children. The finding that vegan children had better cholesterol levels supports previous research showing cardiovascular benefits of plant-based diets. The normal growth in vegan children is consistent with other recent studies, though some older research raised more concerns. This study provides reassuring evidence that well-planned plant-based diets can support healthy child development.

This study took a snapshot at one point in time, so we can’t be sure about long-term effects or cause and effect. The sample size of 142 children is moderate—larger studies might reveal differences that weren’t detected here. The study was done in the Czech Republic, where food availability and fortification practices may differ from other countries, so results might not apply everywhere. The researchers couldn’t randomly assign families to different diets (for ethical reasons), so they compared families who had already chosen their diets, which means other lifestyle factors might differ between groups. The study didn’t measure some nutrients that are sometimes of concern in vegan diets, like iron or calcium. Finally, the lower iodine levels in vegan children, while not affecting thyroid function in this snapshot, could potentially become a problem over many years if not addressed.

The Bottom Line

If you’re considering a plant-based diet for your child: (1) It appears safe for normal growth and development based on this evidence. (2) Make sure to include reliable sources of iodine, such as iodized salt, seaweed, or fortified plant-based products. (3) Include sources of vitamin B12, either through fortified foods or supplements, since this is harder to get from plants. (4) Ensure adequate calcium and iron through varied plant foods or supplements. (5) Have your child’s doctor monitor their growth and nutrient levels with periodic blood tests. These recommendations have moderate confidence based on this study plus existing research.

This research is most relevant to families considering or already following vegan or vegetarian diets, particularly those with children. It’s also important for pediatricians and nutritionists advising families about plant-based eating. Parents concerned about their child’s heart health may find the cholesterol benefits interesting. However, this study doesn’t mean everyone should become vegan—it simply shows that plant-based diets can work well for children when planned carefully. Families with meat-eating diets don’t need to change based on this one study.

The children in this study had been on their respective diets since birth, so the benefits (like better cholesterol) and concerns (like lower iodine) developed over years. You wouldn’t see major changes in a few weeks. If you’re switching your child to a plant-based diet, growth and basic health markers might take several months to stabilize. Nutrient levels could change within weeks to months depending on food choices. It’s wise to have blood tests done 2-3 months after starting a new diet, then annually, to monitor nutrient status.

Want to Apply This Research?

  • Track iodine intake daily by logging iodized salt use, seaweed products, fortified plant milks, or iodine supplements. Set a weekly goal (for example, 3-4 servings of iodine-containing foods per week) and monitor whether you’re meeting it.
  • If using a nutrition app, add iodine-rich foods to your frequent foods list: iodized salt, nori seaweed, fortified plant-based milks, and iodine supplements. Create a weekly meal plan that includes at least one iodine source daily. Set reminders to take B12 supplements if following a vegan diet.
  • Use the app to track not just calories and macronutrients, but also specific micronutrients: iodine, B12, iron, calcium, and zinc. Set monthly check-in reminders to review whether you’re consistently meeting targets for these nutrients. Share this data with your doctor at annual check-ups to ensure your plant-based diet is meeting your family’s nutritional needs.

This research suggests that well-planned vegan and vegetarian diets can support normal child growth and development, with potential cardiovascular benefits. However, this study has limitations and represents one point in time. Before making significant dietary changes for your child, especially removing entire food groups, consult with your pediatrician or a registered dietitian. They can assess your child’s individual nutritional needs, monitor growth and development, and recommend appropriate supplements (such as iodine or B12) if needed. This information is educational and should not replace professional medical advice. Individual results may vary based on food choices, genetics, and other health factors.