Does a plant-based diet lead to poorer bone health?

In Europe, where a reported 4% of consumers follow a vegan diet, plant-based is rising in popularity.

Concern for animal welfare and the environmental impacts of livestock farming are contributing to the move away from products containing meat, dairy and eggs.

As is health, with some research associating plant-based diets with lower blood pressure and cholesterol, lower rates of heart disease, type 2 diabetes, and some forms of cancer.

However, the diet has also been linked to some negative health associations, such as impaired bone health.

In an effort to identify all risks and benefits of following a vegan diet, researchers from the German Federal Institute for Risk Assessment (BfR) have undertaken a cross-sectional study to compare the bone-health of vegans and non-vegans.

The results are in…​

In the study, the BfR assessed the bone health of 36 vegans as well as 36 people following a mixed food diet. The ‘omnivorous’ diet involved the consumption of at least three portions of meat, or two portions of meat and two portions of processed meat, per week.

The researchers assessed participants’ bone health with an ultrasound measurement of the heel bone.

Findings revealed differences in bone health between the two groups: on average, people following a vegan diet had lower ultrasound values compared to the other group. “This indicates poorer bone health,” ​noted the BfR.

The scientists also determined biomarkers in blood and urine to identify specific nutrients that might be related to diet and bone health. Out of 28 parameters of nutritional status and bone metabolism, the researchers identified 12 biomarkers most strongly associated with bone health. These include the amino acid lysine and vitamins A and B6.

In most cases, results indicated that the combination of these biomarkers was present in lower concentrations in vegans, prompting the researchers to suggest nutrient levels as a possible explanation for the poorer bone health.

“A vegan diet is often health-conscious. However, our scientific findings indicate that a vegan diet does affect bone health,” ​said BfR President Professor Dr Andreas Hansel.

Are vegans getting enough of the right nutrients?​

While noting that additional studies are required to support its findings, the BfR’s results do suggest that a plant-based diet could be responsible for reduced bone heath in vegans compared to omnivores.

The Vegan Society said it would similarly encourage more studies analysing correlations between diet, nutrients, and bone health.

“The Vegan Society understands that bone health is a complex topic and would always welcome further research on the matter, especially in relation to people who choose a vegan lifestyle,” ​the charity’s dietician Heather Russell told FoodNavigator.

Responding to the study, Russell stressed the differences between bone health and risk of bone fracture. “In this particular paper, it’s good to be aware that the measures of bone health are not as useful as direct monitoring of fracture risk in larger groups of vegans, and the differences observed in the measures used are barely statistically significant.”​

The study does, however, support The Vegan Society’s recommendations for bone health, we were told. “For example, a well-planned vegan diet features calcium-rich foods like calcium-set tofu and fortified plant milk, which often contains other valuable nutrients like vitamins D, B12 and B2.”​

Concerning nutritional planning, the BfR paper highlights that vegans should pay attention to their intakes of protein, iodine, selenium and vitamin B12. “We recommend that meals include sources of good quality protein, such as kidney beans, lentils, chickpeas and soya,” ​said The Vegan Society’s dietician.

Appropriate supplementation is also important, she stressed, which could mean taking a vitamin and mineral supplement that contains vitamin B12, vitamin D, iodine and selenium.

Source:​ Nutrients​
‘Vegan Diet and Bone Health – Results from the Cross-Sectional RBVD Study’
Published 21 February 2021
DOI: https://doi.org/10.3390/nu13020685
Authors : Juilane Menzel, Klaus Abraham, Gabriele Stangl, Per Magne Ueland, Rima Obeid, Matthias Schulze, Isabelle Herter-Aeberli, Tanja Schwerdtle and Cornelia Weikert.