Researchers and policy makers are waiting for more randomized controlled trials to come out before they improve recommendations for vitamin D intake requirements. Randomized controlled trials are considered the “gold standard” of research because they can very strictly discern if an intervention (like vitamin D) has a causative effect versus just an association. And if there is an effect, what is the effect? Positive? Negative?
This past year, there were quite a few randomized controlled trials using vitamin D. The list below is by no means a comprehensive list, but lists quite a few randomized controlled trials that were published in 2012. These here are RCTs that either (a) the Vitamin D Council already covered, (b) received quite a bit media coverage or (c) popped up in a PubMed search of “vitamin D,” with the filter of “randomized controlled trial.”
I omitted including several RCTs that just looked at “markers” of disease. Of these, quite a few looked at vitamin D’s effect on markers of diabetes or markers of cardiovascular disease; both of which vitamin D shows a repeated mixed effect on markers of these diseases. Longer RCTs underway will be able to look at the effect of vitamin D on these diseases beyond just markers.
So, here they are. Thanks for all your support this 2012, and we look forward to seeing more trials in 2013.
- In a UK study, 305 adults were randomized to take either 400 or 1,000 IU/day for one year to see if there was any effect on cardiovascular risk factors. They found no effect. The low dosage leaves more study to be desired.
- In a study out of Egypt, Dr Shedeed administered 1,000 IU of vitamin D/day or placebo to 80 infants with heart failure for 12 weeks. At the end of the trial, Dr Shedeed observed a significant improvement of heart failure score, left-ventricular end-diastolic diameter, left-ventricular end-systolic diameter and ejection fraction.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/02/28/infant-heart-failure-and-vitamin-d-supplementation/
- Researchers administered 50,000 IU/week for 8 weeks or placebo on 151 adults to see if vitamin D had any effect on cholesterol. In 8 week’s time, vitamin D did not have an effect.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/10/08/rct-shows-curious-relationship-between-d-and-cholesterol/
- Researchers wanted to know if vitamin D could reduce the occurrence of exacerbations in patients with chronic obstructive pulmonary disease. They found that only patients that started with levels less than 10 ng/ml saw a reduction in exacerbations after dosing with 100,000 IU of vitamin D once per month or placebo. Although the researchers were disappointed with the results, this study is a good reminder that it’s important to screen levels in COPD patients and make sure they do not have severe deficiency.
Read Jim Larsen’s blog on the study here: http://blog.vitamindcouncil.org/2012/02/18/high-doses-of-vitamin-d-to-reduce-exacerbations-in-copd-a-closer-look/
- In a trial of only 30 patients, a one-time dose of 250,000 IU of vitamin D in patients with cystic fibrosis decreased the need for antibiotics, the need to visit the hospital and reduced mortality risk five-fold.
Read our full blog on the study here: http://blog.vitamindcouncil.org/2012/05/03/rct-shows-vitamin-d-may-benefit-patients-with-cystic-fibrosis/
- In a study out of Iran, researchers wanted to know if vitamin D combined with Prozac could work better than just Prozac alone in treating depression. They administered 1,500 IU/day. After four weeks, they found a significant improvement in the vitamin D plus Prozac group compared to just Prozac alone.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/11/06/rct-vitamin-d-and-prozac/
- In another study that administered vitamin D by itself at 40,000 IU/week for 6 months, vitamin D was no better than placebo in reducing depressive symptoms. An important distinction here is to note that these patients were not necessarily depressed at baseline or at any point during the study.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/07/20/can-vitamin-d-supplementation-help-relieve-the-symptoms-of-depression/
General Pain and Well-Being
- Researchers wanted to see if vitamin D could ease pain symptoms in patients with sickle cell disease. They administered 4,000 to 100,000 IU of vitamin D once per week or placebo. They found patients who received vitamin D experienced less “pain days” and improved general well-being.
- Researchers out of Italy wanted to know if vitamin D could reduce musculoskeletal pain in patients taking bisphosphonates. They administered a onetime dose of 300,000 IU and then the patients were clinically evaluated for pain after 7 days. Vitamin D indeed reduced pain.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/09/24/fosamax-jaw-part-1-d-reduces-inflammation-and-pain-after-osteoporosis-treatment/
- Researchers wanted to know if vitamin D could improve symptoms of general muscle pain for non-Western immigrants living in the Netherlands. They administered a onetime dose of 150,000 IU or placebo at baseline and 6 weeks. After 12 weeks, the vitamin D group showed better improvement in ability to walk stairs and reported less pain.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/11/15/rct-vitamin-d-improves-musculoskeletal-pain-in-non-western-immigrants/
- In a study out of Israel, researchers randomized fifty patients with hepatitis C to take either 2,000 IU of vitamin D/day for 24 weeks in conjunction with traditional therapy or just traditional therapy. They found the vitamin D group had better viral response.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/03/27/rct-shows-benefits-of-vitamin-d-supplementation-among-hepatitis-c-patients/
- In a very recent study, vitamin D at 2,000 IU/day reduced flare-ups and antibodies in patients with lupus. They administered this dose for one year in 178 patients.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/12/29/vitamin-d-helps-control-lupus-says-new-randomized-control-trial/
- Researchers wanted to know if vitamin D as an add on therapy to interferon β-1b could reduce disease activity in an MRI scan. They found that 20,000 IU of vitamin D/week reduced activity but did not reduce relapse rate.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/09/08/rct-vitamin-d-supplementation-in-patients-with-ms/
- Another study out of Norway also administered 20,000 IU/week or placebo for 96 weeks and found no effects on multiple-sclerosis associated outcomes.
Kampman MT et al. Effect of vitamin D3 supplementation on relapses, disease progression, and measures of function in persons with multiple sclerosis: exploratory outcomes from a double-blind randomised controlled trial. Mult Scler., 2012.
- In a study out of New Zealand, 322 participants took 100,000 IU of vitamin D once per month or placebo for 18 months. They found that vitamin D does not help the incidence or severity of respiratory tract infections.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/10/04/a-closer-look-vitamin-d-no-match-for-common-cold/
- In another study out of Mongolia, researchers randomized 247 children to 300 IU of vitamin D/day in fortified milk or placebo for three winter months. They found that vitamin D reduced the incidence of respiratory infections.
- In yet another study, 4,000 IU of vitamin D per day for one year reduced the incidence of respiratory infections and the need for antibiotics compared to placebo. This study differs from the New Zealand study in that they administered daily doses and the participants had low levels to begin with.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/12/22/new-study-says-vitamin-d-fights-respiratory-infections-reduces-need-for-antibiotics/
- Researchers administered 1,600 IU of vitamin D/day or placebo in 60 patients with atopic dermatitis to see if it could improve the severity of the condition. The vitamin D group did indeed improve the condition while placebo did not.
- Researchers out of Brazil wanted to see if vitamin D could help aid the healing of leg ulcers. They administered 50,000 IU of vitamin D/week for two months versus placebo. They found a trend that vitamin D helped reduce the size of leg ulcers.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/12/19/rct-vitamin-d-may-help-heal-leg-ulcers/
Traumatic Brain Injury
- Patients admitted to the hospital for traumatic brain injury were injected with one mg/kg of progesterone intramuscularly every 12 hours for 5 days and also 200 IU/kg of vitamin D once-a-day for 5 days. For a 150 lb person, this would be 13,600 IU of vitamin D/day for five days. They compared this treatment to placebo or progesterone alone. They found that vitamin D and progesterone improved consciousness best and decreased mortality.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/12/18/rct-vitamin-d-levels-and-traumatic-brain-injury/
- Researchers wanted to see if vitamin D supplementation could reduce the prevalence of tuberculosis skin test conversion in 120 Mongolian children. They administered 800 IU/day for six months and found a trend toward fewer conversions in the vitamin D group.
Read our blog on the study here: http://blog.vitamindcouncil.org/2012/09/21/rct-vitamin-d-supplementation-and-tb-in-mongolian-children/