Supplementation with vitamin D and calcium could support bone health status in healthy adults consuming a plant protein-centric diet, according to a 12-week clinical trial. Published in the Journal of Nutrition (DOI: https://doi.org/10.1093/jn/nxaa264), results suggest a diet high in plant-based protein could accelerate bone turnover due to low consumption levels of vitamin D and calcium. 

In the study, 136 subjects (107 female and 29 male, aged 20-69 years old) were given different ratios of animal-protein (AP) and plant-protein (PP) based intervention diets – 1) 70% AP: 30% PP, 2) 50% AP: 50% PP, and 3) 30% AP: 70% PP. Following dietary adaption, participants were examined for bone formation, bone resorption, mineral metabolism markers, and nutrient intakes.

Researchers suggested that due to lower levels of vitamin D and calcium in PP-based food sources, plant-based protein diets could cause bone resorption (destruction of bone tissues) in healthy adults. “Dietary intakes of calcium and vitamin D were below the recommended levels in the plant group,” the researchers from the Universities of Helsinki and Oulu noted. Interestingly, they also found that subjects with a previous history of vitamin D supplementation kept constant levels of parathyroid hormone (PTH)—a regulator of bone turnover—while PTH levels for those following a high PP-based diet who had no history of vitamin D supplementation were significantly higher. In the PP-based diet, protein sources included soy, beans, peas, seeds and nuts, and cereal products such as oats, rye, wheat and barley. Those following a higher PP-based diet still obtained slightly lesser protein levels than the other groups.

In sustainable plant-based diets, vitamin D and calcium supplementation could ensure adequate intake levels of these nutrients. Vitamin D deficiency is a common issue among vegans and omnivores alike. Further, vitamin D levels are low and only present in small amounts among vegan options. Thus, fortified vitamin D supplementation is most likely to fulfil this whitespace gap in providing vegan consumers’ optimal health.  The recommended dietary allowance of calcium and vitamin D for young adults is 1x10⁶ μg/day and 15 μg/day, respectively, for males and females^1,2.  

References