Here’s a big list of randomized control trial experiments involving vitamin D:
Does High Dose Vitamin D Supplementation Enhance Cognition? A Randomized Trial in Healthy Adults (2017)
Conclusion: Supplementing with 4,000 IU of vitamin D3 a day was found to be effective for improving non-verbal memory in adults – especially in deficient subjects.
Linking Vitamin D Status, Executive Functioning and Self-Perceived Mental Health in Adolescents Through Multivariate Analysis: A Randomized Double-Blind Placebo Control Trial (2017)
Conclusion: A randomized double-blind placebo-controlled trial involving 50 Norwegian adolescents found that those given vitamin D supplements performed better on cognitive tests compared to the placebo group.
Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women: A Randomized Clinical Trial (2017)
Conclusion: 2,064 elderly women were given either a daily dose of 2,000IU of vitamin D and 1,500mg of calcium or a daily placebo for 4 years. The cancer rates were measured over the course of the study and the vitamin D group had a slightly lower cancer rate. One possible reason for why the vitamin D group had only a slightly lower rate is that the women actually had decent vitamin D levels going into the study, possibly making the effects of supplemental vitamin D not as powerful as if the women had been deficient.
Vitamin D Supplementation for Premenstrual Syndrome-Related Mood Disorders in Adolescents with Severe Hypovitaminosis D (2016)
Conclusion: In a randomized control trial involving 158 vitamin D-deficient teenage girls and young women, the girls given high doses of vitamin D adequate for correcting their deficiencies experienced significantly less severe PMS over the four-month period compared to the placebo group.
Effect of Vitamin D3 on Self-Perceived Fatigue: A Double-Blind Randomized Placebo-Controlled Trial (2016)
Conclusion: A study of 120 vitamin D-deficient adults complaining of fatigue were enrolled in a 4-week-long double-blind placebo-controlled trial where they were either given a single dose of 100,000 IU of vitamin D or a placebo. The vitamin D group reported experiencing significantly improved energy levels compared to the placebo group and more members of the vitamin D group reported being cured entirely of fatigue symptoms. The study also found that those who experienced the biggest increases in their vitamin D levels also experienced the biggest improvements in their fatigue symptoms.
Randomized Controlled Trial of Vitamin D Supplementation in Children with Autism Spectrum Disorder (2016)
Conclusion: In a 4-month, double-blinded, randomized clinical trial involving 109 autistic children from six different autism treatment centers in Assiut City, Egypt, those receiving vitamin D therapy showed significant improvement in their autism symptoms compared to the placebo group.
A Randomized Controlled Trial of Vitamin D Supplementation on Perinatal Depression: In Iranian Pregnant Mothers (2016)
Conclusion: This randomized control trial study split 169 pregnant Iranian women in their third trimester into two groups. One group received a placebo, the other received 2,000 IU of vitamin D3 daily for the duration of their pregnancy. Compared to the placebo group, the mothers receiving vitamin D had higher vitamin D levels and lower depression scores during the last month of pregnancy and the two months after childbirth. “The present trial showed that consuming 2000 IU vitamin D3 daily during late pregnancy was effective in decreasing perinatal depression levels.” Alarmingly, this study also found that 72% of the mothers were suffering from vitamin D-deficiency at baseline.
Note: much research has shown that 2,000 IU of vitamin D3 is inadequate for adults who don’t get much unprotected sun exposure. One wonders how much better the depression scores would have been with 5,000 IU of vitamin D daily.
Conclusion: 60 adult tuberculosis patients were enrolled in a randomized, case-controlled clinical trial testing the effectiveness of vitamin D for TB treatment. All were taking anti-tuberculosis drugs, but half were given a one-time vitamin D dose of 200,000 IU. The vitamin D group experienced a “rapid decline” in their tuberculosis severity compared to the control group. The study also found that 90% of all the enrolled TB patients had low vitamin D levels. “Vitamin D accelerates the improvement observed in vitamin D supplemented TB therapy. Vitamin D is safe when added to anti-tuberculous drugs. Vitamin D deficiency/insufficiency is common among TB patients.”
Conclusion: 200 old ladies were randomly split into two groups. One got vitamin D and one got placebos. Their vaginas were evaluated before treatment, at three months, and at six months to test the effects of vitamin D on vaginal health. Researchers found that the vitamin D group displayed “significantly” better vaginal health at both follow ups and vaginal health improved as vitamin D levels improved.
Treatment of Vitamin D Deficiency is an Effective Method in the Elimination of Asymptomatic Bacterial Vaginosis: A Placebo-Controlled Randomized Clinical Trial (2015)
Conclusion: Out of a group of 208 women with both bacterial vaginosis and vitamin D deficiency, half were randomly assigned in this study to take a small 2,000 IU vitamin D3 dose daily for 15 weeks and the other half received a placebo during that time. Vaginal and blood samples were taken before and after the trial. The cure rate for the vitamin D group was 63% vs only 19% in the control group. Keep in mind that 2,000 IU is a very small dose for an adult, so what would the results have been with a higher dose? Our bodies are capable of producing well over 20,000 IU from one sunbathing session.
Conclusion: 44 postmenopausal women were randomly assigned to receive either vitamin D vaginal suppositories or placebo vaginal suppositories daily for 8 weeks to test the effects of vitmamin D on old-age vaginal atrophy. At the end of the study, those who received the vitamin D suppositories had a much higher count of superficial cells in their vaginal epithelium, lower pH levels, lower reporting of vaginal pain, lower reports of vaginal dryness, and lower reports of vaginal paleness.
The Influence of Winter Vitamin D Supplementation on Muscle Function and Injury Occurrence in Elite Ballet Dancers: A Controlled Study (2014)
Conclusion: A four-month study of 24 ballet dancers found that those supplementing with 2000 IU of vitamin D daily were isometrically stronger, could jump higher, and suffered fewer injuries compared to the control group.
Vitamin D Prevents Cognitive Decline and Enhances Hippocampal Synaptic Function in Aging Rats (2014)
Conclusion: Rats given higher doses of vitamin D performed better in cognitive tests compared to rats given lower doses of vitamin D.
Vitamin D and Nifedipine in the Treatment of Chinese Patients with Grades I-II Essential Hypertension: A Randomized Placebo-Controlled Trial (2014)
Conclusion: Randomized placebo-controlled trial gave one group of 63 hypertension patients 2,000 IU of vitamin D daily, another group of 63 hypertension patients received a placebo. The vitamin D group experienced a reduction in their blood pressure.
Vitamin D Increases Cellular Turnover and Functionally Restores the Skeletal Muscle After Crush Injury in Rats (2013)
Conclusion: In a study where male rats were given crush injuries, those given a giant dose of vitamin D recovered faster.
The Effect of Vitamin D Supplementation on Inflammatory and Hemostatic Markers and Disease Activity in Patients with Systemic Lupus Erythematosus: A Randomized Placebo-Controlled Trial (2013)
Conclusion: This randomized placebo-controlled trial took 267 lupus patients and had them take either 2000 IU of vitamin D3 daily for a year or had them take a placebo for a year. After a year of vitamin D supplementation the treatment group exhibited significantly improved inflammatory markers and disease activity compared to the placebo group.What would happen if they took more than 2,000 IU daily? Other findings were that the lupus patients had a lower average vitamin D level than a control group, 69% of them had low levels, and 39% were clinically deficient.
Effect of Vitamin D3 Supplementation on Upper Respiratory Tract Infections in Healthy Adults – The VIDARIS Randomized Controlled Trial (2012)
Conclusion: This 18-month-long randomized, double-blind, placebo-controlled trial of 322 healthy New Zealand adults tested the effect of high-dose oral vitamin D supplementation on upper respiratory tract infection rates. Subjects receiving the vitamin D were given 200,000 IU of vitamin D monthly the first two months and then 100,000 IU monthly for the rest of the 18 months. The vitamin D group had only a slightly lower rate of URTIs compared to the placebo group. 100,000 IU per month averages out to about 3,500 IU per day of vitamin D, which is probably not enough for the average adult. The researchers also speculate the possibility that daily dosing of vitamin D may be more effective than monthly mega-dosing. This study did find, however, that, contrary to what the medical establishment states, 3,500 IU of vitamin D daily is a perfectly safe long-term dose, did not cause a single case of hypercalcemia, and resulted in a consistent, year-round, optimal mean vitamin D level.
Conclusion: A 4-month double-blind randomized placebo-controlled trial of 37 obese black adults found that those given vitamin D supplementation experienced a significant increase in telomerase activity, suggesting that vitamin D “may improve telomere maintenance and prevent cell senescence and counteract obesity-induced acceleration of cellular aging.”
Assessment of Vitamin D Concentration in Non-Supplemented Professional Athletes and Healthy Adults During the Winter Months in the UK: Implications for Skeletal Muscle Function (2012)
Conclusion: A study of athletes in the UK found that 62% had low vitamin D levels. 8 weeks of ingesting 5,000 IU of vitamin D daily significantly improved sprinting and vertical jump performance compared to the placebo group.
Randomized Trial of Vitamin D Supplementation and Risk of Acute Respiratory Infection in Mongolia (2012)
Conclusion: In a randomized control trial involving 247 Mongolian schoolchildren during winter, those given a measly 300 IU of vitamin D daily through vitamin D-fortified milk experienced fewer acute respiratory infections compared to school children given non-fortified milk.
Vitamin D Supplementation for Nonspecific Musculoskeletal Pain in Non-Western Immigrants: A Randomized Controlled Trial (2012)
Conclusion: 84 patients seeking treatment for non-specific musculoskeletal pain were enrolled into a randomized, placebo-controlled trial where patients received either a single bolus dose of 150,000IU vitamin D or a placebo. 6 weeks later the vitamin D group reported a significantly higher reduction in pain compared to the placebo group.
Conclusion: A year-long randomized control trial involving 162 men found that those who supplemented with 3,000 IU of vitamin D daily experienced significant testosterone increases compared to the placebo group.
A 16-Week Randomized Clinical Trial of 2000 International Units Daily Vitamin D3 Supplementation in Black Youth: 25-Hydroxyvitamin D, Adiposity, and Arterial Stiffness (2010)
Conclusion: A 4-month study of 44 black teenagers found that 95% had low vitamin D levels and that supplementing with 2,000 IU of vitamin D daily was effective for reducing arterial stiffness and increasing vitamin D levels. The study also found that the vitamin D levels of the obese subjects rose less than the leaner subjects. Although 2,000 IU daily was effective in raising levels, only 56% achieved sufficient levels after the four months.
Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza A in Schoolchildren (2010)
Conclusion: In this randomized, double-blind, placebo-controlled trial involving 334 school children over a 4-month period, the vitamin D group experienced nearly 50% fewer colds and even fewer asthma attacks compared to the placebo group.
Fall Prevention with Supplemental and Active Forms of Vitamin D: A Meta-Analysis of Randomised Controlled Trials (2009)
Conclusion: “Supplemental vitamin D in a dose of 700-1000 IU a day reduced the risk of falling among older individuals by 19%.”
Conclusion: In a four-year population-based, double-blind, randomized placebo-controlled trial involving 1179 postmenopausal Nebraska women, women receiving a daily dose of 1500mg/day of supplemental calcium and 1100 IU/day of Vitamin D had a 77% lower risk for all types of cancer compared to the placebo group.
Effects of Vitamin D Supplementation on Symptoms of Depression in Overweight and Obese Subjects: Randomized Double Blind Trial (2008)
Conclusion: 441 obese participants were enrolled into a randomized, double-blind, placebo-controlled trial testing the effectiveness of vitamin D for depression. Subjects were given either 20,000 IU vitamin D weekly for one year, 40,000 IU weekly for one year, or placebo weekly for one year. At the end of the study those in the vitamin D groups exhibited improved depression scores, but the placebo group did not. Those with lower vitamin D levels were also found to score worse depression scores compared to those with higher vitamin D levels.
A Higher Dose of Vitamin D Reduces the Risk of Falls in Nursing Home Residents: A Randomized, Multiple-Dose Study (2007)
Conclusion: In a 5-month study of 124 nursing home residents, those given 800 IU of vitamin D daily suffered 72% fewer falls compared to the placebo group.
Conclusion: 4-year study had 1,179 elderly white Nebraska women take a daily calcium supplement, calcium + vitamin D, or a placebo. The calcium plus vitamin D group had the lowest cancer incidence. “Improving calcium and vitamin D nutritional status substantially reduces all-cancer risk in postmenopausal women.”
Effect of Vitamin D Replacement on Musculoskeletal Parameters in School Children: A Randomized Controlled Trial (2006)
Conclusion: For a one-year period 179 girls ages 10-17 were given either a weekly placebo, low dose of vitamin D, or higher dose of vitamin D. After one year the girls given the higher dose of vitamin D showed the biggest increase in lean muscle mass and bone density, especially among the younger girls.
Effect of Cholecalciferol Plus Calcium on Falling in Ambulatory Older Men and Women: A 3-Year Randomized Controlled Trial (2006)
Conclusion: In a 3-year-long randomized, double-blind, placebo-controlled experiment of elderly men and women, 700 IU of vitamin D and 500mg of calcium supplemented daily proved to be effective for reducing the risk of falling in the women by 46%.
Vitamin D and Cancer (2006)
Conclusions: Two groups of mice were given subcutaneous implantations of mouse colon cancer cells. One group was severely vitamin D-deficient, the other group had much higher vitamin D levels. 19 days later the vitamin D-deficient mice had tumors that were 60% larger than the mice with the better vitamin D levels.
Fracture Prevention With Vitamin D Supplementation: A Meta-analysis of Randomized Controlled Trials (2005)
Conclusion: “Oral vitamin D supplementation between 700 to 800 IU/d appears to reduce the risk of hip and any nonvertebral fractures in ambulatory or institutionalized elderly persons.”
Low-Dose Vitamin D Prevents Muscular Atrophy and Reduces Falls and Hip Fractures in Women After Stroke: A Randomized Controlled Trial (2005)
Conclusion: A two-year study of 96 elderly, female stroke victims found that those supplementing with 1000 IU of vitamin D2 daily suffered fewer falls and hip fractures, demonstrated improved muscular strength, and enjoyed an increase in the number and size of type 2 muscle fibers compared to the placebo group.
Conclusion: In this randomized, placebo-controlled experiment, 139 elderly patients with a history of falls were given either a 600,000 IU megadose of vitamin D2 or a placebo. At baseline and 6 months later they were evaluated for postural sway, reaction time, physical performance, and leg strength. At 6 months, the supplemented group had higher vitamin D levels and demonstrated superior reaction time and functional performance compared to the placebo group – who actually exhibited deteriorating physical performance. It’s important to note that almost all studies comparing vitamin D2 and D3 have found D2 to be only about 25% as potent as D3 and a dose of 600,000 IU per 6 months averages out to only about 3,500 IU per day, which is unlikely enough for elderly people to get their levels into an optimal range. “Vitamin D supplementation, in fallers with vitamin D insufficiency, has a significant beneficial effect on functional performance, reaction time and balance, but not muscle strength. This suggests that vitamin D supplementation improves neuromuscular or neuroprotective function, which may in part explain the mechanism whereby vitamin D reduces falls and fractures.”
Vitamin D Requirements During Lactation: High-Dose Maternal Supplementation as Therapy to Prevent Hypovitaminosis D for Both the Mother and the Nursing Infant (2004)
Conclusion: This randomized control trial found that breastfeeding mothers need at least 4,000 IU of vitamin D daily to ensure their breastfeeding infants are getting enough vitamin D.
Randomized Comparison of the Effects of the Vitamin D3 Adequate Intake Versus 100 mcg (4000 IU) Per Day on Biochemical Responses and the Wellbeing of Patients (2004)
Conclusion: Two randomized trials where participants were either given 600 IU of vitamin D daily or 4,000 IU of vitamin D daily for three months found that those given the higher dose of 4,000 IU had better vitamin D levels and better well-being scores upon evaluation at the end of the trial.
Conclusion: Researches found from two experiments that increasing people’s vitamin D levels significantly improves calcium absorption.
The Effect of Vitamin D3 on Insulin Secretion and Peripheral Insulin Sensitivity in Type 2 Diabetic Patients (2003)
Conclusion: In a control trial experiment involving ten vitamin D-deficient type-2 diabetic women and 17 same-age, same-weight, non-diabetic females, taking just 1300 IU of vitamin D daily was found to be effective for increasing vitamin D levels by 75% and decreasing insulin resistance by 21%. “ We suggest vitamin D3 deficiency may at least partly contribute to the impairment of insulin secretion and probably of insulin action. Our results suggest that vitamin D3 supplementation could be an element in the complex treatment of type 2 diabetes.”
Conclusion: In this study of 122 elderly female nursing home residents, those given 800 IU of vitamin D daily for three months experienced 49% fewer falls compared to those not given vitamin D.
Effect of Four Monthly Oral Vitamin D3 (Cholecalciferol) Supplementation on Fractures and Mortality in Men and Women Living in the Community: Randomised Double-Blind Controlled Trial (2003)
Conclusion: A five-year randomized control trial involving 2,686 elderly men and women found that those receiving a 100,000 IU dose of vitamin D3 every four months suffered fewer fractures compared to the placebo group and had a slightly lower mortality rate.
Conclusion: In a three year-long randomized control trial involving 145 subjects over the age of 65, those who took calcium and vitamin D supplements had better tooth retention compared to the placebo group.
Effects of a Short-Term Vitamin D(3) and Calcium Supplementation on Blood Pressure and Parathyroid Hormone Levels in Elderly Women (2001)
Conclusion: A study of 148 vitamin D-deficient elderly women found that supplementing with 1200mg of calcium and 800 IU of vitamin D daily was effective for measurably lowering blood pressure.
Effects of a Short-Term Vitamin D and Calcium Supplementation on Body Sway and Secondary Hyperparathyroidism in Elderly Women (2000)
Conclusion: A 1-year study of 148 elderly women found that those given a daily dose of 800 IU of vitamin D enjoyed 9% less body sway and fewer falls than the non-vitamin D group. Researchers concluded that vitamin D and calcium supplementation may prevent falls and fall-related fractures.
Conclusion: Osteomalacia patients experienced improved physical performance following three months of vitamin D treatment. Another study was performed on 55 vitamin D-deficient veiled Arab women living in Denmark who were experiencing reduced muscle function due to hypovitaminosis D myopathy. They were put on high-dose vitamin D treatment for 6 months and showed improved muscle function after 3 months and 6 months compared to a control group.
Conclusion: In vitamin D experiments carried out on a group of 19 obese people and a group of 19 normal weight people, the obese group experienced 57% lower vitamin D level increases following UVB irradiation compared to the non-obese group.
Conclusion: In this particular randomized control trial, high-dose vitamin D therapy proved to be an effective treatment for alleviating depressive symptoms of seasonal affective disorder. Could winter vitamin D-deficiency resulting from reduced UVB solar radiation be playing a role in seasonal affective disorder?
Conclusion: This random double-blind placebo-controlled trial found vitamin D3 supplementation to be significantly effective for alleviating depression from seasonal affective disorder.
1,25-Dihydroxycholecalciferol Inhibits the Progression of Arthritis in Murine Models of Human Arthritis (1998)
Conclusion: Vitamin D is an effective treatment for reducing arthritis symptoms in mice.
Conclusion: In a randomized control trial experiment involving 96 seasonal affective disorder patients, three weeks of bright light therapy proved to have an antidepressant effect on winter depression sufferers.
Conclusion: In a 6-month randomized control trial comparing the effects of 10,000 lx bright light with 500 lx placebo light on women with late luteal phase dysphoric disorder, it was found that bright light therapy (you know, like SUNLIGHT) was effective for significantly reducing PMS symptoms and improving mood.
1,25-Dihydroxycholecalciferol Inhibits the Progression of Arthritis in Murine Models of Human Arthritis (1998)
Conclusion: Vitamin D is an effective treatment for reducing arthritis symptoms in mice.
Ultraviolet Irradiation Corrects Vitamin D Deficiency and Suppresses Secondary Hyperparathyroidism in the Elderly (1998)
Conclusion: 45 elderly, female nursing home patients were enrolled in a 3-month randomized clinical trial where they either received (1) an extremely mild dose of UVB exposure three times per week, (2) 400 IU of oral vitamin D3 per day (very, very small dose), or (3) no treatment at all. At the beginning of the study 95% of patients were clinically deficient in vitamin D (with 60% being severely deficient), after the three months of treatment the UVB and oral vitamin D groups both enjoyed a doubling of their vitamin D levels. Although their vitamin D levels were still insufficient, the level increase is still impressive considering how small the dose of UVB and vitamin D they were being given. The researchers concluded that UVB exposure and oral vitamin D are basically equally effective for raising and maintaining vitamin D levels. The control group receiving no treatment demonstrated zero changes in their vitamin D levels.
Effect of Calcium and Vitamin D Supplementation on Bone Density in Men and Women 65 Years of Age or Older (1997)
Conclusion: In a 3-year, double-blind, placebo-controlled trial involving 389 elderly people, the group being treated with calcium and vitamin D had better bone density and fewer nonvertebral fractures at the end of the three years compared to the placebo group.
1,25-Dihydroxyvitamin D3 Reversibly Blocks the Progression of Relapsing Encephalomyelitis, a Model of Multiple Sclerosis (1996)
Conclusion: Administration of vitamin D was shown to be effective for completely preventing and stopping the progression of a multiple sclerosis-like autoimmune disease artificially induced in mice. Cessation of vitamin D administration resulted in a resumption of the disease’s progression.
Efficacy and Safety of Topical Calcitriol (1,25-dihydroxyvitamin d3) for the Treatment of Psoriasis (1996)
Conclusion: Topical vitamin D is a safe and effective treatment for psoriasis.
Maternal Consumption of a Low Vitamin D Diet Retards Metabolic and Contractile Development in the Neonatal Rat Heart (1995)
Conclusion: In a randomized control trial with rats, low maternal intake of vitamin D resulted in offspring with smaller hearts compared to offspring from mothers with higher vitamin D intake.
Morning Bright Light Therapy for Sleep and Behavior Disorders in Elderly Patients with Dementia (1994)
Conclusion: Morning bright light therapy was shown to be effective for improving sleep and behavior disorders in demented elderly patients.
Conclusion: In an 18-month-long randomized control trial experiment involving 3,270 elderly women, participants being treated with supplemental calcium and vitamin D suffered 32% fewer nonvertebral fractures compared to a placebo group.
Conclusion: Over a 5-year period 341 elderly people were given annual vitamin D megadose injections (150,000 IU – 300,000 IU vitamin D2) and their fracture rate during that period was compared to a group of 458 matched controls not receiving vitamin D. The vitamin D group experienced 6% fewer fractures than the control group. This is actually impressive considering that an annual dose of 150,000-300,000 IU amounts to only about 400 IU – 800 IU per day, which leading vitamin D experts agree is completely inadequate for adults, possibly even inadequate for infants, and even more inadequate for seniors. Vitamin D2 has also been found to be only about 25% as effective for raising human vitamin D levels than vitamin D3 and the half life of vitamin D is only a few months max, making an annual megadose the least reliable way of maintaining year-round adequate vitamin D status. Despite the vitamin D group receiving essentially meaninglessly insufficient vitamin D treatment, they experienced measurably superior health outcomes and no signs of vitamin D toxicity were observed following the 300,000 IU megadoses.
Conclusion: For 18 months 1634 elderly women received a daily calcium supplement and 800 IU of vitamin D3 and their fracture rates, bone density, and parathyroid hormone levels were compared to another 1636 elderly women receiving placebos. At the end of the study the vitamin D group had suffered 43% fewer hip fractures, 32% fewer nonvertebral fractures, a vitamin D blood level increase of 162%, and parathyroid hormone level reduction of 44% compared to the placebo group. The vitamin D group also enjoyed a 2.7% increase in their bone mineral density, whereas the placebo group suffered a 4.6% decrease in their bone mineral density.
Conclusion: In a randomized control trial of pregnant Asian women living in Britain, the mothers receiving vitamin D supplementation gained weight at a faster rate in their third trimester and had heavier babies.
Conclusion: In a double-blind, placebo-controlled experiment involving 126 pregnant Asian women in their last trimester, those given 1000 IU of vitamin D2 gained weight faster and gave birth to bigger babies with adequate vitamin D levels and slight skeletal development differences compared to the placebo group.
Cod Liver Oil: A Five-Year Study of its Value for Reducing Industrial Absenteeism Caused by Colds and Respiratory Disease (1936)
Conclusion: In a five-year study, daily ingestion of vitamin D-rich cod liver oil was found to be effective for reducing the number of colds worker’s experienced.