Vitamin D is known as the "Sunshine Vitamin" and it was once thought that a deficiency in it was rare and that it was only involved in calcium homoeostasis in bones and that a lack of it caused only Rickets. Recent research has shown that not only is Vitamin D involved in a whole host of bodily processes, but also that an insufficiency in it is very common, leading to an increased risk factor for a whole host of degenerative diseases, such as Coronary Heart Disease and Cancer.
What is Vitamin D?
There's a good overview on Vitamin D here.
Here's a presentation called Vitamin D and Prevention of Chronic Diseases.
How common is Vitamin D deficiency?
According to Hyppönen and Power, in a large sample of the white British population born in 1958, 60.9% of subjects had serum 25(OH)D (the active metabolite of Vitamin D) of less than 75nmol/L in Summer & Autumn, and 87.1% had serum 25(OH)D of less than 75nmol/L in Winter & Spring.
Here's my experience of Vitamin D3. For many years, I was struggling to cope with my job and I eventually took early retirement on the grounds of ill-health. In mid-2006 I was given a serum 25(OH)D test and the result was 73nmol/L. As the Reference Range for serum 25(OH)D is 50-200 nmol/L, I was technically not deficient in Vitamin D. Subsequent events suggested otherwise.
In January 2007, after reading the above study and a study by Vieth, Kimball, Hu and Walfish, I began to supplement with 2,000iu/day of Vitamin D3 and also used a UVB+IR lamp for 3 minutes each night. At first, nothing happened and I was pretty sceptical about getting any improvement. However, after about 8 weeks, I began to notice an awakening in my brain. This continued, and by March 2007, I was feeling quite perky. Friends commented on the fact that I had become very chatty and I was also waking early in the morning raring to go, totally unlike my former self. In May 2007, I had another serum 25(OH)D test and the result was 115nmol/L. Another interesting result was my serum triglycerides, something that's usually always higher than desirable. My TGs were 1.4mmol/L (RR less than 1.8mmol/L). This was the lowest result since tests began in 2002.
I began to get bored with standing around stark naked in front of a UV lamp for 3 minutes each night and I stopped doing this. Slowly, my brain began to go back to sleep. I couldn't understand why as I thought that 2,000iu/day of Vitamin D3 (5 x RDA) was more than enough.
In November 2007, I had another serum 25(OH)D test. When I saw my endocrinologist in December 2007, I was quite shocked to see that the result was now 70nmol/L. I immediately increased my Vitamin D3 intake to 5,000iu/day (12.5 x RDA) and within 2 weeks, my brain started to wake up again. In May 2008, serum 25(OH)D was 173nmol/L and in September 2008 it was 163nmol/L. I'm still taking 5,000iu/day.
See also The urgent need to recommend an intake of vitamin D that is effective.
What foods contain it?
For a list of the foods highest in Vitamin D, see here. Beware of foods that have been supplemented, as Vitamin D2 may have been used. This is less effective than Vitamin D3 according to Armas, Hollis and Heaney. Vegetarians and vegans may not want to eat foods containing Vitamin D3 as this is sourced from animals (e.g. the lanolin from a sheep's coat). Eating the Standard English Diet, it is difficult to obtain 5,000iu/day of Vitamin D. The cheapest way to get a lot of it is by going out in the sun in a swimsuit for 20 or so minutes in the middle of the day in Summer and Autumn, which costs absolutely nothing. As Vitamin D is fat-soluble, the body can build up stores to keep itself supplied during Winter and Spring.
Vitamin D deficiency, Insulin Resistance and The Metabolic Syndrome and Type 2 Diabetes
According to Hyppönen and Power, there is a strong association between decreasing 25(OH)D, increasing Body Mass Index (BMI) and increasing HbA1c (glycated haemoglobin).
According to Khaw, Wareham, Bingham, Luben, Welch and Day, increasing HbA1c is associated with increasing Relative Risk of mortality, summarised here.
According to Chiu, Chu, Go and Saad, there is a positive correlation of 25(OH)D concentration with insulin sensitivity and a negative effect of hypovitaminosis D on ß cell function. Subjects with hypovitaminosis D are at higher Relative Risk of Insulin Resistance and The Metabolic Syndrome.
In January 2003, I had Impaired Glucose Tolerance (fasting serum glucose = 6.8mmol/L and 2 hours post-75g glucose load serum glucose = 8.7mmol/L). A sandwich used to send me to sleep.
By September 2008, I had Normal Glucose Tolerance (fasting serum glucose = 5.0mmol/L and 2 hours post-75g glucose load serum glucose = 3.7mmol/L). I also no longer suffered from hyperinsulinaemic sleeps. Result!
Vitamin D deficiency and Cancer
According to Lappe, Travers-Gustafson, Davies, Recker and Heaney, subjects receiving 1400-1500mg/day supplemental calcium and 1100iu/day supplemental Vitamin D3 have a Relative Risk of getting any type of cancer of 0.402 which is equivalent to a 60% reduction in the risk of getting cancer compared to the non-supplementing group.
If the first 12 months results are discarded (to exclude any subjects who already had cancer when they started the study), the RR is 0.232 which is equivalent to a 77% reduction in the risk of getting cancer. I wonder what the result would have been had 5,000iu/day of Vitamin D3 been used.
See also Diaz, Paraskeva, Thomas, Binderup and Hague.
Vitamin D deficiency and Mental function
According to Vieth, Kimball, Hu and Walfish as mentioned above, supplementing with 4,000iu/day of Vitamin D3 produces a large reduction in the "Miserableness Factor" without affecting serum Calcium levels.
According to Wilkins, Sheline, Roe, Birge and Morris, Vitamin D deficiency is associated with low mood and worse cognitive performance in older adults.
According to Gloth, Alam and Hollis, Improvement in 25(OH) D is significantly associated with improvement in depression scale scores in a group of 15 subjects with SAD.
According to Cherniack, Troen, Florez, Roos and Levis, Hypovitaminosis D is prevalent among older adults, and several studies suggest an association between hypovitaminosis D and basic and executive cognitive functions, depression, bipolar disorder, and schizophrenia.
Vitamin D deficiency and High Blood Pressure
According to Forman, Giovannucci, Holmes, Bischoff-Ferrari, Tworoger, Willett and Curhan, plasma 25(OH)D levels are inversely associated with the risk of incident hypertension.
Vitamin D deficiency and the Immune System
According to Cannell, Vieth, Umhau, Holick, Grant, Madronich, Garland and Giovannucci, Vitamin D deficiency predisposes children to respiratory infections.
According to Ginanjar, Sumariyono, Setiati and Setiyohadi, The active form of vitamin D produces and maintains self immunologic tolerance.
Vitamin D Deficiency and Falls
According to Dharmarajan, Akula, Kuppachi and Norkus, in the pilot study of older adults with gait imbalance and falls, vitamin D deficiency was observed in 54% of patients tested and previously unrecognised.
Vitamin D Deficiency and Chronic Pain
According to Plotnikoff and Quigley, all patients with persistent, non-specific musculoskeletal pain are at high risk for the consequences of unrecognised and untreated severe hypovitaminosis D.
According to Al Faraj and Al Mutairi, Vitamin D deficiency is a major contributor to chronic low back pain in areas where vitamin D deficiency is endemic.
According to Gloth, Lindsay, Zelesnick and Greenough, there may be a pain syndrome associated with vitamin D depletion that appears as hyperaesthesia worsened by light, superficial pressure or even small increments of movement.
But doesn't the sun damage the skin and cause skin cancer?
Inappropriate sun exposure can certainly damage the skin.
Chronic overexposure to the sun (e.g. farmers and other outdoor workers) causes wrinkly, leathery skin and skin cancers such as Basal Cell Carcinoma and Squamous Cell Carcinoma. These are benign skin cancers which are easily removed and rarely fatal.
Acute overexposure to the sun (e.g. people getting severe sunburn on foreign holidays) causes the much more serious Malignant Melanoma. This condition, if not caught early enough, has a very high risk of mortality.
However, sensible sun exposure has more benefits than hazards. See Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin D as a possible explanation. EDIT: See also Is Vitamin D Shooting Me in the Foot?
Is it possible to get too much Vitamin D?
It is possible to overdose with Vitamin D by supplementation. According to Vieth, published cases of vitamin D toxicity with hypercalcaemia, for which the 25(OH)D concentration and vitamin D dose are known, all involve intakes of greater than 40,000iu/day. See also Pharmacokinetics of vitamin D toxicity.
People suffering from Sarcoidosis, Primary Hyperparathyroidism, a history of Calcium Kidney Stones and Milk-Alkali Syndrome need to consult their GP before supplementing with Vitamin D. People prescribed Warfarin also need to be careful, as Warfarin is a Vitamin K recycling antagonist, which can result in calcification of tissues.
It isn't possible to overdose by sun exposure, as the metabolic processes down-regulate when ~10,000iu has been produced. To find out when the sun is strong enough to produce Vitamin D in your skin, see the Vitamin D Synthesis in Human Skin Calculator.
EDIT: Insufficient Vitamin A can result in Vitamin D toxicity. See Is Vitamin D Safe? Still Depends on Vitamins A and K! Testimonials and a Human Study.
EDIT: Vitamins A & D are synergistic, not antagonistic. See New Evidence of Synergy Between Vitamins A and D: Protection Against Autoimmune Diseases.
I've found a cheap source of 5,000iu Vitamin D3 gelcaps. See http://www.iherb.com/Vitamin-D3-5-000-IU-360-Softgels/18335 That's a 1 year supply for about £10. First-time buyers can use discount code NIG935 to get $5 off their first order. Standard shipping is $4.
10,000iu Vitamin D3 gelcaps are also available. See http://www.iherb.com/Healthy-Origins-Vitamin-D3-10-000-IU-360-Softgels/21298
Addendum:- Editorials, meta-studies and human Randomised Controlled Trials on Vitamin D and Vitamin D3 over the period 2005 to the present.The Role of Vitamin D in Cancer Prevention
Estimates of optimal vitamin D status.
Prevalence of Vitamin D inadequacy among postmenopausal North American women receiving osteoporosis therapy.
Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials.
The re-emerging burden of rickets: a decade of experience from Sydney.
An excess of widespread pain among South Asians: are low levels of vitamin D implicated?
Vitamin D is associated with improved survival in early-stage non-small cell lung cancer patients.
Vitamin D and prevention of colorectal cancer.
Should older people in residential care receive vitamin D to prevent falls? Results of a randomized trial.
Effect of vitamin D replacement on musculoskeletal parameters in school children: a randomized controlled trial.
Effect of cholecalciferol plus calcium on falling in ambulatory older men and women: a 3-year randomized controlled trial.
Vitamin D supplementation improves cytokine profiles in patients with congestive heart failure: a double-blind, randomized, placebo-controlled trial.
Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes.
Risk factors for vitamin D inadequacy among women with osteoporosis: an international epidemiological study.
A system for improving vitamin D nutrition in residential care.
Impact of dietary and lifestyle on vitamin D in healthy student girls aged 11-15 years.
How much vitamin D3 do the elderly need?
Lower levels of plasma 25-hydroxyvitamin D among young adults at diagnosis of autoimmune type 1 diabetes compared with control subjects: results from the nationwide Diabetes Incidence Study in Sweden (DISS).
A meta-analysis of second cancers after a diagnosis of nonmelanoma skin cancer: additional evidence that solar ultraviolet-B irradiance reduces the risk of internal cancers.
Risk assessment for vitamin D.
Supplementation with calcium + vitamin D enhances the beneficial effect of weight loss on plasma lipid and lipoprotein concentrations.
Serum 25(OH)D levels, dietary intake of vitamin D, and colorectal adenoma recurrence.
The effects of calcium and vitamin D supplementation on blood glucose and markers of inflammation in nondiabetic adults.
Optimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis.
A higher dose of vitamin d reduces the risk of falls in nursing home residents: a randomized, multiple-dose study.
Potentially modifiable determinants of vitamin D status in an older population in the Netherlands: the Hoorn Study.
Fracture prevention with vitamin D supplementation: considering the inconsistent results.
A prospective study of plasma vitamin D metabolites, vitamin D receptor polymorphisms, and prostate cancer.
The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis.
A single dose of vitamin D enhances immunity to mycobacteria.
Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin D as a possible explanation.
Vitamin D intake and breast cancer risk in postmenopausal women: the Iowa Women's Health Study.
Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial.
Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D.
Vitamin D deficiency in multicultural primary care: a case series of 299 patients.
Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials.
Efficacy of different doses and time intervals of oral vitamin D supplementation with or without calcium in elderly nursing home residents.
Vitamin D status and response to Vitamin D(3) in obese vs. non-obese African American children.
Vitamin D and skin physiology: a D-lightful story.
Additive benefit of higher testosterone levels and vitamin D plus calcium supplementation in regard to fall risk reduction among older men and women.
Rapid correction of low vitamin D status in nursing home residents.
Effects of a long-term vitamin D and calcium supplementation on falls and parameters of muscle function in community-dwelling older individuals.
Prevalence of vitamin d insufficiency in patients with Parkinson disease and Alzheimer disease.
Exploration of association of 1,25-OH2D3 with augmentation index, a composite measure of arterial stiffness.
Vitamin D and prevention of colorectal adenoma: a meta-analysis.
The tolerability and biochemical effects of high-dose bolus vitamin D2 and D3 supplementation in patients with vitamin D insufficiency.
Administration of oral vitamin D induces cathelicidin production in atopic individuals.
Estimation of the dietary requirement for vitamin D in healthy adults.
Changes in 25-Hydroxyvitamin D3 to oral treatment with vitamin D3 in postmenopausal females with osteoporosis.
Vitamin D or hormone D deficiency in autoimmune rheumatic diseases, including undifferentiated connective tissue disease.
High-dose oral vitamin D3 supplementation in the elderly.
A double-blind, randomized, placebo-controlled trial of the short-term effect of vitamin D3 supplementation on insulin sensitivity in apparently healthy, middle-aged, centrally obese men.
Vitamin D deficiency in older men.
Serum vitamin D and risk of pancreatic cancer in the prostate, lung, colorectal, and ovarian screening trial.
Vitamin D supplementation during Antarctic winter.
Vitamin D insufficiency and treatment with oral vitamin D3 in northern-dwelling patients with chronic kidney disease.
Long-term effects of giving nursing home residents bread fortified with 125 microg (5000 IU) vitamin D(3) per daily serving.
Effects of vitamin D and calcium supplementation on markers of apoptosis in normal colon mucosa: a randomized, double-blind, placebo-controlled clinical trial.
Estimation of the dietary requirement for vitamin D in free-living adults >=64 y of age.
Vitamin D supplementation enhances the beneficial effects of weight loss on cardiovascular disease risk markers.
Plasma 25-hydroxyvitamin D concentration and metabolic syndrome among middle-aged and elderly Chinese individuals.
Meta-analysis: longitudinal studies of serum vitamin D and colorectal cancer risk.
Effect of vitamin D supplementation in the institutionalized elderly.
Calcitriol ointment 3 microg/g is safe and effective over 52 weeks for the treatment of mild to moderate plaque psoriasis.
Association between 25-hydroxyvitamin D levels and cognitive performance in middle-aged and older European men.
Low parathyroid hormone levels in bedridden geriatric patients with vitamin D deficiency.
Increased levels of 25 hydroxyvitamin D and 1,25-dihydroxyvitamin D after rosuvastatin treatment: a novel pleiotropic effect of statins?
Effect of vitamin D deficiency and replacement on endothelial function in asymptomatic subjects.
Vitamin D and depressive symptoms in women during the winter: a pilot study.
Treatment of vitamin D deficiency increases lower limb muscle strength in institutionalized older people independently of regular physical activity: a randomized double-blind controlled trial.
Vitamin D, parathyroid hormone and the metabolic syndrome in middle-aged and older European men.
Vitamin D supplementation reduces insulin resistance in South Asian women living in New Zealand who are insulin resistant and vitamin D deficient - a randomised, placebo-controlled trial.
Fall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trials.
Meta-analysis of vitamin D, calcium and the prevention of breast cancer.
Effects of vitamin d and calcium on proliferation and differentiation in normal colon mucosa: a randomized clinical trial.
Combination of alfacalcidol with calcium can improve quadriceps muscle strength in elderly ambulatory Thai women who have hypovitaminosis D: a randomized controlled trial.
Vitamin D(3) induces expression of human cathelicidin antimicrobial peptide 18 in newborns.
Levels of vitamin D and cardiometabolic disorders: systematic review and meta-analysis.
No significant effect on bone mineral density by high doses of vitamin D3 given to overweight subjects for one year.
Effects of supplemental vitamin D and calcium on oxidative DNA damage marker in normal colorectal mucosa: a randomized clinical trial.
Vitamin D levels, lung function, and steroid response in adult asthma.
Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations:a nested case-control study.
Pandemic preparedness for swine flu influenza in the United States.
Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren.
Vitamin D supplementation suppresses age-induced bone turnover in older women who are vitamin D deficient.
Suppression of C-terminal telopeptide in hypovitaminosis D requires calcium as well as vitamin D.
A phase I/II dose-escalation trial of vitamin D3 and calcium in multiple sclerosis.
Milk fortified with the current adequate intake for vitamin D (5 microg) increases serum 25-hydroxyvitamin D compared to control milk but is not sufficient to prevent a seasonal decline in young women.
Vitamin D-vitamin K interaction: effect of vitamin D supplementation on serum percentage undercarboxylated osteocalcin, a sensitive measure of vitamin K status, in Danish girls.
Vitamin D status and impact of vitamin D3 and/or calcium supplementation in a randomized pilot study in the Southeastern United States.
Calcium/vitamin D supplementation and coronary artery calcification in the Women's Health Initiative.
Circulating 25-hydroxyvitamin D and risk of pancreatic cancer: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers.*
A 16-week randomized clinical trial of 2000 international units daily vitamin D3 supplementation in black youth: 25-hydroxyvitamin D, adiposity, and arterial stiffness.
The effect of narrowband UV-B treatment for psoriasis on vitamin D status during wintertime in Ireland.
Effects of vitamin D supplementation to children diagnosed with pneumonia in Kabul: a randomised controlled trial.
Dairy calcium intake, serum vitamin D, and successful weight loss.
Atorvastatin increases 25-hydroxy vitamin D concentrations in patients with polycystic ovary syndrome.
A randomized controlled trial of the effects of vitamin D on muscle strength and mobility in older women with vitamin D insufficiency.
Serum 25-hydroxyvitamin D concentration is associated with functional capacity in older adults with heart failure.
Effect of vitamin D supplementation on testosterone levels in men.
Vitamin D production depends on ultraviolet-B dose but not on dose rate: a randomized controlled trial.
Vitamin D(3) is more potent than vitamin D(2) in humans.
Nutrients and foods for the primary prevention of asthma and allergy: systematic review and meta-analysis.
High-dose vitamin D(3) during intensive-phase antimicrobial treatment of pulmonary tuberculosis: a double-blind randomised controlled trial.
Circulating 25-hydroxyvitamin D levels and frailty in older men: the osteoporotic fractures in men study.
Association of low serum 25-hydroxyvitamin D levels and mortality in the critically ill.
Effects of vitamin D supplementation on 25-hydroxyvitamin D, high-density lipoprotein cholesterol, and other cardiovascular disease risk markers in subjects with elevated waist circumference.
Changes in balance, functional performance and fall risk following whole body vibration training and vitamin D supplementation in institutionalized elderly women. A 6 month randomized controlled trial.
Diet induced thermogenesis, fat oxidation and food intake following sequential meals: influence of calcium and vitamin D.
The response of elderly veterans to daily vitamin D3 supplementation of 2,000 IU: a pilot efficacy study.
Meta-analysis: Circulating vitamin D and ovarian cancer risk.
Relation of vitamin D level to maximal oxygen uptake in adults.
Vitamin D status in patients with stage IV colorectal cancer: findings from Intergroup trial N9741.
Circulating levels of vitamin D and colon and rectal cancer: the Physicians' Health Study and a meta-analysis of prospective studies.
Burning daylight: balancing vitamin D requirements with sensible sun exposure.
Relationships between vitamin D status and cardio-metabolic risk factors in young European adults.
Latitude is significantly associated with the prevalence of multiple sclerosis: a meta-analysis.
Vitamin D status and early age-related macular degeneration in postmenopausal women.
Vitamin D and clinical disease progression in HIV infection: results from the EuroSIDA study.
Annual high-dose vitamin D3 and mental well-being: randomised controlled trial.
Vitamin D status and outcomes in heart failure patients.
The impact of vitamin D status on periodontal surgery outcomes.
The role of paricalcitol on proteinuria.
Effects of weight loss on serum vitamin D in postmenopausal women.
Vitamin D status and mortality risk in CKD: a meta-analysis of prospective studies.
Vitamin D intake and risk of cardiovascular disease in US men and women.
Meta-analysis: Serum vitamin D and colorectal adenoma risk.
Calcium plus vitamin D supplementation and the risk of nonmelanoma and melanoma skin cancer: post hoc analyses of the women's health initiative randomized controlled trial.
Effects of vitamin D and calcium supplementation on pancreatic β cell function, insulin sensitivity, and glycemia in adults at high risk of diabetes: the Calcium and Vitamin D for Diabetes Mellitus (CaDDM) randomized controlled trial.
Vitamin D supplementation for prevention of mortality in adults.
The effect of calcium plus vitamin D on risk for invasive cancer: results of the Women's Health Initiative (WHI) calcium plus vitamin D randomized clinical trial.
New clinical trials with vitamin D and analogs in renal disease.
The relation between vitamin D deficiency and fibromyalgia syndrome in women.
Interventions for latent autoimmune diabetes (LADA) in adults.
Calcium and vitamin D supplementation is associated with decreased abdominal visceral adipose tissue in overweight and obese adults.
Effect of vitamin D supplementation on muscle strength, gait and balance in older adults: a systematic review and meta-analysis.
Vitamin D3 and the risk of CVD in overweight and obese women: a randomised controlled trial.
Low 25-hydroxyvitamin D is associated with increased mortality in female nursing home residents.
Improvement of vitamin D status resulted in amelioration of biomarkers of systemic inflammation in the subjects with type 2 diabetes.
Vitamin D supplementation in infants with chronic congestive heart failure.
Vitamin D reduces musculoskeletal pain after infusion of zoledronic acid for postmenopausal osteoporosis.
Consumption of vitamin D-and calcium-fortified soft white cheese lowers the biochemical marker of bone resorption TRAP 5b in postmenopausal women at moderate risk of osteoporosis fracture.
Vitamin D improves viral response in hepatitis C genotype 2-3 naïve patients.
Vitamin D supplementation in the treatment of atopic dermatitis: a clinical trial study.
Effect of vitamin D repletion on urinary calcium excretion among kidney stone formers.
25-Hydroxyvitamin D levels and the risk of stroke: a prospective study and meta-analysis.
Improvement of vitamin D status via daily intake of fortified yogurt drink either with or without extra calcium ameliorates systemic inflammatory biomarkers, including adipokines, in the subjects with type 2 diabetes.
Treatment of vitamin D insufficiency in children and adolescents with inflammatory bowel disease: a randomized clinical trial comparing three regimens.
Therapeutic effects of calcium & vitamin D supplementation in women with PCOS.
Higher vitamin D dietary intake is associated with lower risk of alzheimer's disease: a 7-year follow-up.
Vitamin D3 supplementation at 4000 international units per day for one year results in a decrease of positive cores at repeat biopsy in subjects with low-risk prostate cancer under active surveillance.
Comparison of narrowband ultraviolet B exposure and oral vitamin D substitution on serum 25-hydroxyvitamin D concentration.
The relation between sunscreen layer thickness and vitamin D production after ultraviolet B exposure: a randomized clinical trial.
Circulating 25-hydroxyvitamin D concentration and the risk of type 2 diabetes: results from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort and updated meta-analysis of prospective studies.
Vitamin D3 therapy corrects the tissue sensitivity to angiotensin ii akin to the action of a converting enzyme inhibitor in obese hypertensives: an interventional study.
The effect of combined calcium and cholecalciferol supplementation on bone mineral density in elderly women with moderate chronic kidney disease.
Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis.
Relative effectiveness of oral 25-hydroxyvitamin D3 and vitamin D3 in raising wintertime serum 25-hydroxyvitamin D in older adults.
Vitamin D supplementation and depression in the women's health initiative calcium and vitamin D trial.
Vitamin D with calcium reduces mortality: patient level pooled analysis of 70,528 patients from eight major vitamin D trials.
An open label, randomized controlled study of oral calcitriol for the treatment of proteinuria in patients with diabetic kidney disease.
Ergocalciferol from mushrooms or supplements consumed with a standard meal increases 25-hydroxyergocalciferol but decreases 25-hydroxycholecalciferol in the serum of healthy adults.
Narrowband ultraviolet B three times per week is more effective in treating vitamin D deficiency than 1600 IU oral vitamin D₃ per day: a randomized clinical trial.
Vitamin D intake is inversely related to risk of developing metabolic syndrome in African American and white men and women over 20 y: the Coronary Artery Risk Development in Young Adults study.
Vitamin D and gestational diabetes: a systematic review and meta-analysis.
Associations between 25-hydroxyvitamin D and weight gain in elderly women.
Effect of cholecalciferol as adjunctive therapy with insulin on protective immunologic profile and decline of residual β-cell function in new-onset type 1 diabetes mellitus.
A pooled analysis of vitamin D dose requirements for fracture prevention.
Determinants and effects of vitamin D supplementation on serum 25-hydroxy-vitamin D levels in patients with rheumatoid arthritis.
Vitamin D is a major determinant of bone mineral density at school age.
Effect of vitamin D and inhaled corticosteroid treatment on lung function in children.
Serum 25-hydroxyvitamin D3 and D2 and non-clinical psychotic experiences in childhood.
Vitamin D deficiency in postmenopausal, healthy women predicts increased cardiovascular events: a 16-year follow-up study.
Randomized trial of vitamin D supplementation and risk of acute respiratory infection in Mongolia.
25-hydroxyvitamin d levels and risk of ischemic heart disease, myocardial infarction, and early death: population-based study and meta-analyses of 18 and 17 studies.
Association of low serum 25-hydroxyvitamin D levels and acute kidney injury in the critically ill.
A 12-week double-blind randomized clinical trial of vitamin D₃ supplementation on body fat mass in healthy overweight and obese women.
Circulating 25-hydroxy-vitamin D and risk of cardiovascular disease: a meta-analysis of prospective studies.
Relation of severe deficiency of vitamin D to cardiovascular mortality during acute coronary syndromes.
Vitamin D reduces left atrial volume in patients with left ventricular hypertrophy and chronic kidney disease.
Interventions for preventing falls in older people in care facilities and hospitals.
Vitamin D and risk of death from vascular and non-vascular causes in the Whitehall study and meta-analyses of 12,000 deaths.
Calcium plus vitamin D3 supplementation facilitated fat loss in overweight and obese college students with very-low calcium consumption: a randomized controlled trial.
Randomized controlled trial of vitamin D supplement on endothelial function in patients with type 2 diabetes.
Effect of vitamin D supplementation on progression of knee pain and cartilage volume loss in patients with symptomatic osteoarthritis: a randomized controlled trial.
Lipoprotein lipase links vitamin D, insulin resistance, and type 2 diabetes: a cross-sectional epidemiological study.
The effect of different doses of vitamin D supplementation on insulin resistance during pregnancy.
Vitamin D and dental caries in controlled clinical trials: systematic review and meta-analysis.
Vitamin D deficiency and depression in adults: systematic review and meta-analysis.
Improving the vitamin D status of vitamin D deficient adults is associated with improved mitochondrial oxidative function in skeletal muscle.
Low 25-OH vitamin D is associated with benign prostatic hyperplasia.
Correcting vitamin D insufficiency improves insulin sensitivity in obese adolescents: a randomized controlled trial.
Vitamin D levels in Alzheimer's and Parkinson's diseases: a meta-analysis.
Supplemental vitamin D and physical performance in COPD: a pilot randomized trial.
Vitamin D and risk of future hypertension: meta-analysis of 283,537 participants.
Randomized clinical trial of vitamin D3 doses on prostatic vitamin D metabolite levels and ki67 labeling in prostate cancer patients.
Randomized, double-blind, placebo-controlled trial of vitamin D supplementation in Parkinson disease.
Anti-inflammatory effect of vitamin D on gingivitis: a dose-response randomised control trial.
Role of vitamin D in children with respiratory tract infection.
Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial.
Vitamin D and multiple sclerosis: what is the clinical impact?
Is hypovitaminosis D associated with abdominal aortic aneurysm, and is there a dose-response relationship?
Plasma vitamin D levels, menopause, and risk of breast cancer: dose-response meta-analysis of prospective studies.
Impact of vitamin D on chronic kidney diseases in non-dialysis patients: a meta-analysis of randomized controlled trials.
Serum 25-hydroxyvitamin D levels and the risk of depression: a systematic review and meta-analysis.
The effect of vitamin D-related interventions on multiple sclerosis relapses: a meta-analysis.
Vitamin D status and physical function in nursing home residents: a 1-year observational study.
Maternal vitamin D status and risk of pre-eclampsia: a systematic review and meta-analysis.
Meta-analysis: vitamin D and non-alcoholic fatty liver disease.
Serum 25-hydroxyvitamin D and breast cancer risk: a meta-analysis of prospective studies.
Treatment with oral active vitamin D is associated with decreased risk of peritonitis and improved survival in patients on peritoneal dialysis.
Vitamin D supplementation affects serum high-sensitivity C-reactive protein, insulin resistance, and biomarkers of oxidative stress in pregnant women.
The role of vitamin D supplementation in the risk of developing pneumonia: three independent case-control studies.
Short-term vitamin D3 supplementation lowers plasma renin activity in patients with stable chronic heart failure: an open-label, blinded end point, randomized prospective trial (VitD-CHF trial).
Vitamin D and psychosis: mini meta-analysis.
Meta-analysis of memory and executive dysfunctions in relation to vitamin D.
Vitamin D intake and lung cancer risk in the Women's Health Initiative.
Association of low serum 25-hydroxyvitamin D levels and sepsis in the critically ill.
Vitamin D favorably alters the cancer promoting prostaglandin cascade.
Vitamin D intake and risk of type 1 diabetes: a meta-analysis of observational studies.
Effect of vitamin D supplementation on antibiotic use: a randomized controlled trial.
Effects of vitamin D supplementation on glucose metabolism, lipid concentrations, inflammation, and oxidative stress in gestational diabetes: a double-blind randomized controlled clinical trial.
Improvement in high-density lipoprotein cholesterol levels in argentine Indian school children after vitamin D supplementation.
Vitamin D supplementation for prevention of mortality in adults.
Beneficial role for supplemental vitamin D3 treatment in chronic urticaria: a randomized study.
Vitamin D3 supplementation during weight loss: a double-blind randomized controlled trial.
Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies.
*See Vitamin D and UV fluctuations for an explanation.
If you fancy doing a search yourself, click on PubMed.