Researchers in Finland compared how bones develop in young children and their parents who eat different types of diets. They looked at children ages 2-7 and adults who followed vegan diets (no animal products), vegetarian diets (no meat but some animal products), or regular diets with meat. The study found that children and adults eating plant-based diets showed signs of faster bone changes, even though they were getting enough vitamin D and calcium. The researchers think this might be related to eating less protein or how the body absorbs calcium from plant foods, but they need more research to understand what this means for long-term bone health.

The Quick Take

  • What they studied: Whether eating only plants (vegan), mostly plants with some animal products (vegetarian), or a regular diet with meat affects how children’s and adults’ bones work and change
  • Who participated: 71 children ages 2-7 years old (about half girls) and 76 adults (mostly in their late 30s, mostly women) from Finland who followed three different eating patterns
  • Key finding: Children and adults eating plant-based diets showed signs of faster bone turnover—meaning their bones were breaking down and rebuilding more quickly—even though they had healthy vitamin D levels and adequate calcium intake
  • What it means for you: If your family eats a plant-based diet, you may want to pay extra attention to protein intake and ensure you’re getting enough calcium from plant sources. However, this is one study and more research is needed before making major diet changes. Talk to your doctor or nutritionist before making decisions based on this research.

The Research Details

This was a research study that compared three groups of people eating different diets. The researchers collected blood samples from 71 children (29 vegan, 18 vegetarian, 24 eating regular diets) and 76 adults (29 vegan, 23 vegetarian, 24 eating regular diets) in Finland. They measured specific markers in the blood that show how fast bones are breaking down and building back up. They also asked families to write down everything they ate for three days to measure how much calcium, vitamin D, and protein they were getting.

The researchers used statistical methods to look for patterns across the three diet groups, adjusting for factors like age, sex, and body weight that could affect bone health. This approach allowed them to see if there were clear trends related to diet type.

Understanding how different diets affect bone development in children is important because bones are still growing and developing during childhood. If plant-based diets affect bone metabolism differently, families following these diets need to know so they can make sure their children get the right nutrients. This study is valuable because there hasn’t been much research on this topic in young children.

This study has some strengths: it measured actual blood markers rather than just asking people about their health, and it included both children and adults. However, the sample size is relatively small (especially for the vegetarian group with only 18 children), which means the results might not apply to all families. The study was done in Finland, so results might be different in other countries with different food availability. The researchers adjusted their analysis for important factors like age and body weight, which strengthens the findings.

What the Results Show

The main finding was that children and adults eating plant-based diets showed signs of increased bone turnover. Specifically, in children, there was a trend toward higher parathyroid hormone levels (a hormone that helps control calcium). In adults, there were trends toward higher levels of bone resorption markers (signs that bone is breaking down) and bone formation markers (signs that new bone is being made).

Despite these differences in bone markers, the study found that vitamin D levels were healthy in all groups (over 70 nmol/l), and most families were taking vitamin D supplements (74-100% across all groups). Calcium intake was approximately adequate in all diet groups, meaning families were getting enough calcium even though they were eating different foods.

One clear difference was protein intake: children and adults eating plant-based diets consumed less protein (12-14% of their daily calories) compared to those eating regular diets (16-17% of daily calories). The researchers think this lower protein intake might explain some of the differences in bone metabolism they observed.

The study found that vitamin D supplement use was very common across all diet groups (74-100%), which helped maintain healthy vitamin D levels even in people eating plant-based diets. This suggests that supplementation is important for bone health regardless of diet type. The researchers also noted that calcium intake was similar across groups, but they raised a question about whether calcium from plant sources is absorbed as well as calcium from animal sources.

This study adds to a small amount of research on plant-based diets and bone health. Previous studies in adults have shown mixed results, with some suggesting plant-based diets might affect bone density. This is one of the first studies to look carefully at young children following plant-based diets, making it a valuable addition to the research. The findings suggest that bone metabolism may work differently in plant-based eaters, but whether this leads to weaker bones later in life is still unclear.

The study has several important limitations. The number of participants is relatively small, especially the vegetarian group, which means the results might not apply to all families. The study only measured bone markers in the blood, not actual bone strength or density, so we don’t know if these changes actually affect how strong children’s bones are. The study was done in Finland where people have good access to vitamin D supplements and fortified foods, so results might be different in other countries. Finally, this is a snapshot in time—the researchers only measured each person once, so we don’t know what happens to bones over years of eating these diets.

The Bottom Line

Based on this research, families following plant-based diets should: (1) Make sure children get adequate protein from plant sources like beans, lentils, nuts, and seeds; (2) Ensure vitamin D supplementation or adequate sun exposure (this study shows supplements are important); (3) Include good sources of calcium like fortified plant milks, leafy greens, and calcium-set tofu; (4) Have regular check-ups with a pediatrician or nutritionist to monitor growth and development. These recommendations have moderate confidence because this is one study with a small sample size.

This research is most relevant to families raising young children (ages 2-7) on plant-based diets. Parents considering switching their young children to plant-based diets should be aware of these findings. Healthcare providers working with families on plant-based diets should pay attention to protein intake and bone health monitoring. This research is less relevant to older children or adults, though the adult findings in this study suggest the patterns may continue. People eating omnivorous diets don’t need to change their behavior based on this research.

The changes in bone markers measured in this study happen relatively quickly and were visible in children and adults already following plant-based diets. However, whether these changes affect actual bone strength takes years to develop. You wouldn’t expect to see major changes in bone health immediately, but consistent attention to protein and calcium intake over months and years is important for long-term bone development.

Want to Apply This Research?

  • If following a plant-based diet, track daily protein intake (target: 1.0-1.2g per kg of body weight for children) and calcium intake (target: 700-1000mg daily depending on age) for 2-week periods monthly to ensure adequacy
  • Add one plant-based protein source to each meal (beans, lentils, tofu, nuts, seeds) and one calcium-rich food (fortified plant milk, leafy greens, tahini, calcium-set tofu) to meals, while maintaining consistent vitamin D supplementation
  • Track weekly protein and calcium intake patterns, monitor growth measurements at regular pediatric visits, and schedule annual nutrition check-ins with a registered dietitian familiar with plant-based diets for children

This research is preliminary and based on a single study with a small sample size. The findings show associations in bone metabolism markers but do not prove that plant-based diets cause weak bones or harm bone health. Parents considering plant-based diets for their children should consult with their pediatrician or a registered dietitian nutritionist before making dietary changes. This information is not a substitute for professional medical advice. Individual bone health depends on many factors including genetics, physical activity, and overall nutrition. Regular monitoring by healthcare providers is recommended for children on any specialized diet.