Elevated vitamin D intake may improve the bone structure of teenage girls

A supplementation with vitamin D may increase bone mass and structural bone parameters in adolescent girls, reports a new study.

The randomized controlled study measured parameters of bone health among 338 boys and girls (with an average age of 13), who received 1,400 IU or 14,000 IU of vitamin D or placebo daily for one year (1). The study results showed that the girls who took the supplements showed a significant increase in bone mass of the hip – 7.9% in the low- and 6.8% in the high-dose vitamin D group – compared to the placebo group (4.2%). In addition, the critical balance between bone thickness and bone width (buckling ratio) at the nar- row neck part of the femur was strengthened by 6.1% in the low- and 2.4% in the high-dose group, com- pared with 1.9% in the placebo group. Boys did not show significant benefits in any parameters measured.

The researchers commented that these study findings may translate into a reduced risk of hip fractures in the girls’ elderly years. Maximizing the build-up of bone during the highly important pubescent years is seen as the best way to reduce the risk of osteoporosis later in life. About 35% of a mature adult’s peak bone mass is built-up during puberty. Another approach is to boost bone density in high-risk post-menopausal women by improved diet or supplements.

According to the scientists, the lack of an apparent effect on bone structure in boys may possibly be due to their higher vitamin D levels at study entry, and possibly the powerful effect of the boys’ larger lean mass and activity level on bone mass and structure, compared to the girls. Alternatively, the observed sexual difference may include the varying effect of sex steroids on bone mass, micro-architecture, muscle and the delayed timing of puberty in boys compared to girls, and the delay in changes in bone geometry in this gender compared to girls.

1. Al-Shaar L. et al. Effect of vitamin D replacement on hip structural geometry in adolescents: A randomized controlled trial. Bone. 2013; 56(2):296–303.