Bone and mineral metabolism in 2-7-year-old Finnish children and their caregivers following vegan, vegetarian, and omnivorous diets.

Abstract

Limited evidence exists on the effects of plant-based diets (PBDs) on bone metabolism, especially in children. We studied bone and mineral metabolism and intakes of bone-related nutrients in 2-7-year-old children and their caregivers who followed vegan, vegetarian (collectively referred to as PBD), and omnivorous diets. Blood samples were collected from 29, 18, and 24 children following vegan, vegetarian, or omnivorous diets (mean age 4.5 ± 1.5 years, 51% girls) and from 29, 23, and 24 adult caregivers, respectively (mean age 38.2 ± 4.4 years, 57% women). Serum tartrate-resistant acid phosphatase 5b (S-TRAP5b), bone-specific alkaline phosphatase (S-BAP), 25-hydroxyvitamin D (S-25(OH)D), and plasma parathyroid hormone (P-PTH) were analysed using linear trends by contrast analysis [adjusted for age, sex, and (standardized) body mass index]. Nutrient intakes were calculated from 3-day food records. Linear trends towards higher concentrations of P-PTH among children and bone resorption marker S-TRAP5b and bone formation marker S-BAP among adults in PBDs were observed (P < 0.05). Mean vitamin D intakes (diet + supplements) were adequate (> 10 µg/d), mean 25(OH)D concentrations were > 70 nmol/l, vitamin D supplement use was common (74-100%), and mean calcium intakes were approximately adequate in all age and diet groups. Protein intake was lower in PBDs (12-14 E%) than in omnivores (16-17 E%) (P < 0.05). Linear trends towards increased bone catabolism among children and accelerated bone turnover among adults following PBDs were observed despite adequate vitamin D status and approximately adequate calcium intake. The role of lower protein intake and calcium bioavailability in PBDs and bone health requires further investigation.