Young adult vegetarians in Shanghai have comparable bone health to omnivores despite lower serum 25(OH) vitamin D in vegans: a cross-sectional study

Abstract

Background and objectives: The association between a vegetarian diet and bone mineral density (BMD) remains unclear, particularly in young adults. This study was designed to compare the bone health status of young vegetarians and omnivores in Shanghai, China.

Methods and study design: A total of 246 vegetarians (following a vegan or lacto-ovo-vegetarian diet for at least 1 year) and 246 age- and sex-matched omnivores were recruited among young adult residents of Shanghai, China. The ultrasound bone mineral density analyser CM-200 was employed to measure calcaneus mineral densities, and blood samples were collected to determine serum 25- hydroxyvitamin D status. Intakes of protein, calcium and vitamin D were assessed by the 24-hour dietary recall method.

Results: The average age of the vegetarians was 32.7±6.5 years, 83.3% of whom were female; 71.3% of the participants had been vegetarians for no more than 5 years. After adjusting for some potential cofounding factors, the serum 25-hydroxyvitamin D concentration of vegans (15.0±13.4 μg/L) was significantly lower than that of omnivores (17.6±8.8 μg/L, p<0.05). The protein, calcium and vitamin D intakes of vegetarians were all lower than those of omnivores (p<0.05). However, there was no significant difference in calcaneus mineral density between vegetarians and omnivores or between vegans and lacto-ovo vegetarians.

Conclusions: Serum 25- hydroxyvitamin D concentrations in vegans, but not in lacto-ovo vegetarians, were slightly lower than those in omnivores. However, short-term vegetarian diets did not result in adverse effects on bone mineral density in young Chinese adults.