Vitamin D and Health

Evidence considered since IOM (Table 14, Annex 2)
Intervention studies
6.88 A 1-year RCT (Islam et al., 2010) reported a beneficial effect (p < 0.001) of vitamin D supplementation
on femur BMD and BMC in premenopausal women in Bangladesh (n=200; age, 16-36y). Participants
received daily vitamin D either alone (10 µg/400 IU), with calcium (600 mg), with calcium plus a
multiple micronutrient (MMN) supplement, or placebo. Mean baseline serum 25(OH)D concentration
was 36 nmol/L. After 1 year, significantly (p < 0.001) higher mean serum 25(OH)D concentrations
were observed in the vitamin D, vitamin D + calcium, vitamin D + calcium + MMN supplemented
groups (increase of 32·2, 32·4, 28·8 nmol/L respectively) but not in the placebo group (increase of
0·6 nmol/L). However, the results of this study should be interpreted with caution since it was
conducted in low-income Bangladeshi women with multiple micronutrient deficiencies and the
findings may not be applicable to healthy young women in the UK.
6.89 No data were identified on vitamin D and indices of bone health in young adult men.
Muscle strength and function
6.90 IOM Report: Muscle strength and function in adults under 50y was not considered.
Evidence considered since IOM report (Table 15, Annex 2)
Systematic review and meta-analysis
6.91 Tomlinson et al. (2015) investigated the effect of vitamin D supplementation on muscle strength in
adults (< 40 y) in a systematic review and meta-analysis of 6 RCTs and 1 controlled trial (n=310; mean
age, 24y). Three studies also administered calcium: in 2 studies both control and vitamin D groups
were required to take calcium; in the 3 rd study, participants were randomised to receive placebo,
calcium, vitamin D 3 , or vitamin D 3 and calcium. Mean baseline serum 25(OH)D concentration of
participants (reported in 5 studies) was 30.8 nmol/L. Overall, vitamin D supplementation significantly
improved upper (p=0.005) and lower (p=0.04) limb muscle strength.
Cohort studies
6.92 No cohort studies could be identified.
Stress fracture prevention
6.93 Stress fractures are caused by repetitive sub-maximal loading of bone which ultimately results in a
decrease in the intrinsic ability of the bone to repair itself, leading to an accumulation of
microdamage. Stress fractures are therefore considered to be reflective of poor bone health and are a
common problem in the younger, physically active population including many athletic groups (e.g.,
long distance runners). They are also a significant problem in military forces in the UK, US and Europe;
for example, in the UK military, the current prevalence of pelvic stress fractures is 8-10% and tibia
stress fractures is 6-7%.
6.94 IOM Report: Data on vitamin D and stress fracture prevention in the younger adult population were
not reviewed. A study that reported a reduction in the incidence of stress fractures in Navy recruits
supplemented with a vitamin D and calcium was cited (Lappe et al., 2008) but its generalisability to
the general population was questioned. This study is considered further below.
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