The evidence shows that vitamin D supplementation provides some benefit in fracture prevention ( likely ∼10–15 % relative reduction ) , particularly at a dose ≥800 IU and with calcium ; a likely benefit in the rate of falls , though it is less clear whether the number of fallers changes ; and a possible small ( ∼5 % ) relative reduction in mortality .
Evidence does not support the use of vitamin D supplementation for the prevention of cancer , respiratory infections or rheumatoid arthritis .
Similarly , evidence does not support vitamin D supplementation for the treatment of multiple sclerosis and rheumatoid arthritis or for improving depression/mental well-being .
Regular testing of 25-hydroxyvitamin D is generally not required , and mega-doses ( ≥300,000 IU ) appear to increase harms .
Over the past decade , a large body of observational evidence has suggested an association between  lower vitamin D status ( 25-hydroxyvitamin D ) and multiple acute and chronic disorders , including cancer , multiple sclerosis , depression and respiratory tract infections .
This evidence has fostered the hypothesis that increasing vitamin D intake may treat and prevent such disorders .
Our objective was to perform a critical analysis of the highest-level evidence for ten common beliefs regarding vitamin D for the prevention of falls , fractures and respiratory tract infections , the reduction of cancer incidence/mortality and overall mortality , and the prevention or treatment of depression/mental well-being , rheumatoid arthritis and multiple sclerosis , as well as maximum dosing and regular testing .
Can vitamin D supplementation prevent winter-time blues? A randomised trial among older women.
BACKGROUND Seasonal Affective Disorder ( SAD ) is a sub-type of depression that only occurs during the winter months . A reduction in vitamin D may be linked to SAD . Since vitamin D deficiency has been reported to be common in older people , vitamin D supplementation may be expected to reduce seasonal mood disturbance in this group . OBJECTIVE To assess the effect of vitamin D supplementation on the mental health of older women . SETTING Primary care in three areas of the UK ( Herts , Newcastle , York ) . SUBJECTS Women aged 70 years or more recruited to the trial in the months May-October . INTERVENTION Eligible women were r and omised to receive calcium and vitamin D supplementation or no supplementation . OUTCOME MEASURE At baseline and the six monthly assessment the mental component score ( MCS ) , calculated from the SF-12 question naire was used to assess participants ' subjective psychological well-being . RESULTS A total of 2117 women recruited to the trial had their baseline measures taken between the months of May-October ( 1205 woman in the control group and 912 women in the intervention group ) . Of these women , 1621 had a  MCS score at baseline and six months . Comparison of the six month mean MCS scores , adjusting for baseline MCS score and age , showed there was no significant difference between the two scores ( p = 0.262 ) . CONCLUSIONS Supplementing elderly women with 800 IU of vitamin D daily did not lead to an improvement in mental health scores
The evidence shows that vitamin D supplementation provides some benefit in fracture prevention ( likely ∼10–15 % relative reduction ) , particularly at a dose ≥800 IU and with calcium ; a likely benefit in the rate of falls , though it is less clear whether the number of fallers changes ; and a possible small ( ∼5 % ) relative reduction in mortality .
Evidence does not support the use of vitamin D supplementation for the prevention of cancer , respiratory infections or rheumatoid arthritis .
Similarly , evidence does not support vitamin D supplementation for the treatment of multiple sclerosis and rheumatoid arthritis or for improving depression/mental well-being .
Regular testing of 25-hydroxyvitamin D is generally not required , and mega-doses ( ≥300,000 IU ) appear to increase harms .
Over the past decade , a large body of observational evidence has suggested an association between  lower vitamin D status ( 25-hydroxyvitamin D ) and multiple acute and chronic disorders , including cancer , multiple sclerosis , depression and respiratory tract infections .
This evidence has fostered the hypothesis that increasing vitamin D intake may treat and prevent such disorders .
Our objective was to perform a critical analysis of the highest-level evidence for ten common beliefs regarding vitamin D for the prevention of falls , fractures and respiratory tract infections , the reduction of cancer incidence/mortality and overall mortality , and the prevention or treatment of depression/mental well-being , rheumatoid arthritis and multiple sclerosis , as well as maximum dosing and regular testing .