How plant-based diets influence bone health

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The adoption of plant-based diets is steadily increasing due to the associated health benefits and sustainability.

However, they also bring challenges, notably the risk of inadequate intake of protein, vitamins, and minerals essential for optimal health.

A study by the University of Helsinki delves into these challenges, particularly focusing on bone health, revealing that insufficient intake of calcium and vitamin D in plant-based diets can pose risks.

Study Overview

The research involved 136 adults following one of three study diets for 12 weeks. The first diet mirrored the average Finnish diet, with approximately 70% of protein derived from animal sources, predominantly cereal products.

The second diet comprised equal proportions of plant and animal protein, and the third diet was predominantly plant-based, with 30% animal protein and 70% plant-based protein.

Dietary Modifications

The sources of animal protein in the diets were partially substituted with plant-based proteins from a variety of legumes, nuts, seeds, and cereals.

Additionally, fluid dairy products, fortified with vitamin D, were partially replaced with plant-based drinks not fortified with calcium or vitamin D. There was a notable reduction in the amount of cheese in the diets with higher plant-based protein.

However, the intake of fish and eggs remained constant across all diets.


The results disclosed a concerning increase in both bone formation and resorption when animal proteins were substituted with plant proteins.

This imbalance could lead to long-term detriment to bone health, correlating with prior research findings of a higher fracture risk among vegetarians.

The researchers attributed the changes in bone metabolism to lower consumption of dairy products, consequently resulting in insufficient intake of calcium and vitamin D.

Implications and Recommendations

The study underscores the critical need for ensuring adequate intake of calcium and vitamin D when adopting a predominantly plant-based diet to maintain bone health.

The recommended intake for adults is 10 micrograms of vitamin D per day, encompassing the total intake from both food and supplements.


While the shift towards plant-based diets is commendable for its myriad benefits, it’s pivotal to balance the dietary components to avoid nutritional deficiencies.

This study sheds light on the possible adverse effects on bone health due to inadequate intake of calcium and vitamin D in plant-based diets.

Thus, a conscious effort to maintain nutritional balance is crucial for individuals following or transitioning to plant-based diets, particularly focusing on nutrients predominantly found in animal products.

For further insight into nutritional science, consider exploring studies on the impact of the Mediterranean diet on brain health, optimal times for vitamin intake to prevent heart diseases, the role of plant nutrients in reducing high blood pressure, and how vitamin D supplements can significantly reduce cancer death risk.

This significant study conducted by Suvi T. Itkonen et al was published in The Journal of Nutrition, serving as a resource for nutritional understanding and providing direction for balanced dietary choices.

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