A recent study from the University of Helsinki has explored how vegan, vegetarian, and omnivorous diets affect bone health in both children and adults.
The study, called MIRA2, focused on key nutrients important for bones, such as calcium, vitamin D, and protein, and how these nutrients affect bone metabolism.
The study involved children between two and seven years old, as well as their caregivers, all living in Helsinki.
Some followed a vegan diet, others a vegetarian diet, and the rest ate an omnivorous diet. Most vegans in the study followed official guidelines for vitamin D and calcium supplements and ate fortified foods.
As a result, they had adequate intakes of both nutrients. Interestingly, children on a vegan diet actually had higher vitamin D intake because they consumed more high-dose supplements.
Blood tests showed that vitamin D levels were adequate in all diet groups. However, the researchers found some differences in bone metabolism. Adults on vegan or vegetarian diets had higher levels of markers that suggest faster bone formation and breakdown.
In children, more plant-based diets were linked to higher levels of parathyroid hormone, which may signal increased bone breakdown. While these results hint at possible long-term concerns for bone health, it’s not yet clear what they mean in real life.
One reason for these differences could be the lower absorption of calcium from plant foods. According to Suvi Itkonen, a docent at the University of Helsinki, fortified plant-based drinks and foods are crucial for getting enough calcium and vitamin D.
Finland is ahead in this area, with many fortified vegan products available and people generally following vitamin supplement recommendations.
The study also found that vegans and vegetarians consumed less protein compared to omnivores. Although the amount was still within a healthy range, the type of protein may matter.
Plant proteins don’t have the same amino acid makeup as animal proteins and may not be absorbed as well. This could partly explain the differences seen in bone metabolism. The researchers plan to study this further by analyzing amino acid intake in more detail.
Because the study was conducted in Helsinki, where vegan foods are common in daycare and shops, the results may not apply to places where vegan options are limited.
The researchers warn that carefully planning a vegan diet is especially important for children. National dietary guidelines now support mostly plant-based eating, but removing a food group means you must find healthy replacements.
To protect bone health, experts recommend choosing calcium- and vitamin D-fortified plant-based drinks and yoghurts, and making sure children take daily vitamin D supplements all year round.
If diets lack fortified foods, dairy, or regular fish, extra vitamin D is especially important during the darker months. This is often the case for people on vegan diets.
Additional findings from the MIRA2 study, such as effects on cholesterol, metabolism, and other nutrients, will be shared in future reports.
The study is published in European Journal of Nutrition.
Copyright © 2025 Knowridge Science Report. All rights reserved.
