Recent meta-analyses reinforce the finding that 10 - 20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people .
Although vitamin D doses were greater than those assessed in the past , we found no new evidence that supplementation could have an effect on most non-skeletal conditions , including cardiovascular disease , adiposity , glucose metabolism , mood disorders , muscular function , tuberculosis , and colorectal adenomas , or on maternal and perinatal conditions .
The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation .
The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations .
There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions , including chronic inflammation , despite use of increased doses of vitamin D , strengthening the hypothesis that low vitamin D status is a consequence of ill health , rather than its cause .
We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections , which would reduce the risk of death in debilitated individuals .
The effects of vitamin D supplementation on maternal and neonatal outcome: A randomized clinical trial
Background : Vitamin D supplementation during pregnancy has been supposed to defend against adverse gestational outcomes . Objective : This r and omized clinical trial study was conducted to assess the effects of 50,000 IU of vitamin D every two weeks supplementation on the incidence of  gestational diabetes ( GDM ) , gestational hypertension , preeclampsia and preterm labor , vitamin D status at term and neonatal outcomes contrasted with pregnant women that received 400 IU vitamin D daily . Material s and Methods : 500 women with gestational age 12 - 16 weeks and serum 25 hydroxy vitamin D ( 25 ( OH ) D ) less than 30 ng/ml r and omly categorized in two groups . Group A received 400 IU vitamin D daily and group B 50,000 IU vitamin D every 2 weeks orally until delivery . Maternal and Neonatal outcomes were assessed in two groups . Results : The incidence of GDM in group B was significantly lower than group A ( 6.7 % versus 13.4 % ) and odds ratio ( 95 % Confidence interval ) was 0.46 ( 0.24 - 0.87 ) ( P=0.01 ) . The mean ± SD level of 25 ( OH ) D at the time of delivery in mothers in group B was significantly higher than A ( 37.9 ± 19.8 versus 27.2 ± 18.8 ng/ml , respectively ) ( P=0.001 ) . There were no differences in the incidence of preeclampsia , gestational hypertension , preterm labor , and low birth weight between two groups . The mean level of 25 ( OH ) D in cord blood of group B was significantly higher than group A ( 37.9 ± 18 versus 29.7 ± 19ng/ml , respectively ) . Anthropometric measures between neonates were not significantly different . Conclusion : Our study showed 50,000 IU vitamin D every 2 weeks decreased the incidence of GDM
Recent meta-analyses reinforce the finding that 10 - 20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people .
Although vitamin D doses were greater than those assessed in the past , we found no new evidence that supplementation could have an effect on most non-skeletal conditions , including cardiovascular disease , adiposity , glucose metabolism , mood disorders , muscular function , tuberculosis , and colorectal adenomas , or on maternal and perinatal conditions .
The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation .
The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations .
There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions , including chronic inflammation , despite use of increased doses of vitamin D , strengthening the hypothesis that low vitamin D status is a consequence of ill health , rather than its cause .
We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections , which would reduce the risk of death in debilitated individuals .