Table of contents
- Definition of RCT
- Why RCTs are typically needed
- When RCTs are not needed, or are inappropriate
- Why blinded RCTs are difficult with Vitamin D
- Intervention category listings on VitaminDWiki has 833 items
- Proof that Vitamin D Works
- See also VitaminDWiki: Random Controlled Trials with vitamin D intervention
- See also VitaminDWiki
- Vitamin D is especially needed during pregnancy
- Also, The Vitamin D Receptor limits the amount of Vitamin D in the blood actually gets to the tissue
- There are 436 items with RCT in the title on VitaminDWiki as of May 2017
- 38 Reasons why there can be a low response to Vitamin D
- RCTS are the only appropriate way to demonstrate the role of vitamin D in health – May 2017
- Those perceiving problems with vitamin D were 20X more likely to not participate in an RCT - July 2016
- 32% of Breast Cancer patients in an RCT failed to consistent take DAILY vitamin D - July 2016
- Vitamin D – wait for Random Controlled Trials, rebuttal – not wait and consider UV – Feb 2015
- Vitamin D clinical trials should be based on Vitamin D tests – Aug 2017
- How to Understand, Refute, and Plan Studies Using Vitamin D - Vaseuez 2017
- Examples of Vitamin D RCTs which did NOT show a benefit
Definition of RCT
Randomized controlled trial Wikipedia
"Randomized controlled trial: (RCT) A study in which people are allocated at random (by chance alone) to receive one of several clinical interventions. One of these interventions is the standard of comparison or control. The control may be a standard practice, a placebo ("sugar pill"), or no intervention at all."
There appear to be 3 types of RCT
- 1) Double blinded
- 2) Single Blinded (just the person running the trial knows who gets each treatment)
- 3) Non-blinded- everyone knows. including those analyzing the results
Why RCTs are typically needed
Reduces possibility of bias
When RCTs are not needed, or are inappropriate
- WikiPedia " RCTs may be unnecessary for treatments that have dramatic and rapid effects relative to the expected stable or progressively worse natural course of the condition treated."
- When there is good other evidence for Vitamin D benefits for long term health problems - which would require very expensive decades long trials
Why blinded RCTs are difficult with Vitamin D
Those getting enough vitamin D to make a difference will quickly know because many aches and pains will go away.
- Within a week or 2 if supplementation starts with a loading dose
- Within a month or 2 if just a maintenance dose is given
Intervention category listings on VitaminDWiki has 833 items
Examples of categories as of May 2017
RCT | |||
Breathing | 23 | ||
Cardiovascular | 8 | ||
Diabetes | 10 | ||
Falls/Fractures | 10 | ||
Hypertension | 6 | ||
Obesity | 7 | ||
Pain | 11 | ||
Pregnancy | 31 |
Proof that Vitamin D Works
86 health problems have proven to be prevented/treated as of July 2019
ADHD, Alcoholic Liver Cirrhosis, ALS, Alzheimer's, Antibiotic Use in Seniors, Asthma, Autism, Autoimmune Diseases, Back pain, Blood Cell Cancer, Breast Cancer, Cardiovascular, Cholesterol, Chronic Hives, Chronic Kidney Disease, Cluster Headaches, Congestive Heart Failure (Infants), COPD, Crohn's Disease, C-Section and Pregnancy Risks, Cystic Fibrosis, Dengue Fever, Depression, Diabetes, Diabetic Neuropathy, Eczema, Epilepsy, Falls, Fatigue, Fatty Liver (Child), Fibromyalgia, Gestational Diabetes, Gingivitis, Growing Pains, Hay Fever, Heart Attack, Hemodialysis, Hepatitis-C, Hip Fractures, Hypertension, ICU survival, Influenza, Irritable Bowel Syndrome, Ischemic Stroke, Knee Osteoarthritis, Leg Ulcers, Long-COVID, Low Birth Weight, Lupus, Male Infertility, Menstrual Pain, Metabolic Syndrome, Middle Ear Infection (Infants), Mite Allergy, Multiple Sclerosis, Non-Alcoholic Fatty Liver Disease, Osteoarthritis, Parkinson's Disease, Perinatal Depression, Pneumonia (Ventilator-associated), Poor Sleep, PreDiabetes, Preeclampsia, Pre-term Birth, Prostate Cancer, Psoriasis, Quality of Life, Raynaud's Pain, Respiratory Tract Infection, Restless Leg Syndrome, Rheumatoid Arthritis, Rickets, Sarcopenia, Sepsis, Short Neonates, Sickle Cell, Stronger Senior Muscles, Survive ICU, TB, Tonsillitis, Trauma Death, Traumatic Brain Injury, Tuberculosis, Ulcerative Colitis, Urinary Tract Infection, Vaginosis, Vertigo, Warts, Weight Loss
Reminder: Translate icon in the upper right selects a different language
Click on underlined items for details
Health Problem | Treat Prevent | Reduction by Vit D | RCT = Randomized Controlled Trial * = link to additional RCT CT = Clinical Trial |
Hypertension | T P | 149 to 142 mm Hg HT risk reduced 10X | RCT* *, 2400 IU. 100,000 IU* When Vitamin D > 40 ng |
Cardiovascular after attack | T | 32 % fewer deaths | CT 1000 IU |
Diabetes Type 1 | P | 85 % | 12,000 kids, 2000 IU |
Diabetes Type 2 | T | 62 % | RCT* CRP reduction, 4000 IU Injection is far better - RCT * RCT 50,000 IU/2weeks + probiotics RCT 5,000 IU daily 6 months |
Back Pain | T | 95 % reduced 50% | 5000/10000 IU 60,000 IU weekly |
Influenza | P | 90 % | RCT *, 2000 IU |
Falls | P | 50% | RCT, 100,000 IU monthly RCT with Meals on Wheels 2016 |
Hip Fractures | P | 30 % | RCT * 800 IU |
Rickets | P | 98 % | Turkey, 400 IU NOT RCT, given to all children |
Raynaud's Syndrome | T | 40 % | RCT, visual scale, 20000 IU Avg |
Menstrual pain | P | 76 % | RCT, 7000 IU Avg, 70% reduction 2018 PMS reduced by half |
Pregnancy risks | P | 50 % | RCT, 4000 IU |
C-section, unplanned | P | 50 % | RCT, 4000 IU, small study |
Low birth weight | P | 60 % | RCT * 1000 IU of D2 |
TB | P | 60 % | RCT, 800 IU |
Breast Cancer | P | 60 % | RCT, 1100 IU (2007) |
Rheumatoid Arthritis pain | T | 40 % | RCT, 500 IU, added to prescription |
Cystic Fibrosis | T | 75 % 2nd study improved | RCT, pilot 4X fewer deaths 250,000 IU RCT, pilot 8,200 IU |
Chronic Kidney | T | 90 to 70 PTH | RCT, 3500 IU, |
Respiratory Tract Infection | P | 63 % | 3 RCT, 4000 IU 1 year 2nd 2000/800 IU 20,000 IU weekly |
Lupus | T T | zero flares Pain reduced | Loading then 100,000 IU monthly, RCT too RCT 4,000 IU |
Sickle Cell | T | Less pain | RCT, up to 100,000 IU/week |
Leg ulcer healing | T | 4X faster | RCT, 50,0000 IU/week, small study |
Traumatic Brain Injury | T | 2X | RCT, 20,0000 IU/day with progesterone |
Parkinson's Disease | T | Stabilized | RCT, 1200 IU/day |
Multiple Sclerosis | P T | 68% 95% were CURED | RCT, 7100 IU prevent pre-MS ==> MS 20,000 to 140,000 IU/day |
Congestive Heart Failure | T | 90 % | RCT, 1000 IU infants (also: Adults, not RCT) |
Middle Ear Infection | P | 30 % | RCT, 1000 IU infants |
Gingivitis | T | 88 % | RCT, 2000 IU |
Muscle in seniors | T | 17 % more muscle | RCT, 4000 IU |
Antibiotic use when >70y | T | 47 % | RCT, 60,000 IU monthly |
Infants taller | Benefit | 1 cm tall | RCT, 50,000 IU weekly, for 8 weeks while pregnant |
Gestational Diabetes | T | Reduced 3X | RCT, 2 doses of 50,000 IU |
After Heart Attack | T | +6% ejection fraction | RCT, 800,000 IU one time |
Prostate Cancer | T | Fewer +cores | RCT, 4000 IU (2012) |
Asthma | P T | Reduced symptoms | RCT, 60K IU/month; RCT 50K IU/week Need good D at 4 weeks into preg. |
Depression | T | Reduced | RCT 300,000 IU injection RCT 1500 IU helped Prozac RCT 50,000 IU weekly, elderly |
Low vitamin D while breastfed | P | All infants > 20 mg | RCT, 5,000 IU |
Fibromyalgia | T | Half of many still has Fibro | RCT, 30-48 ng RCT 50K IU/week |
Hives, Chronic | T | Reduced 40% | RCT, 4000 IU added |
Cholesterol | T | Reduced 4 mg | RCT, 400 IU + Ca |
Weight Loss | T | lost 5 more lbs | RCT, 2000 IU +diet +exercise |
Gestational Diabetes | P | 40% | RCT * , 5,000 IU |
Chronic Obstructive Pulmonary Disease | T | 17X improvement | CT, 50,000 IU weekly RCT 100,000 IU monthly |
Asthma | T | 1/2 Asthma attacks | RCT >42 mg of vitamin D |
Quality of Life (QoL) | T | Nursing Home QoL | CT, 4,000 IU in daily bread |
Death of Critically Ill Patients | T | 20% increase in survivability | RCT 540 K IU loading than 90K monthly |
Restless Leg Syndrome | T | Score 26 ==> 10 | CT, Vitamin D dose size not stated in abstract |
Hepatitis-C | T | Aided normal drugs | RCT 2.000 IU |
Crohn's disease | T | improved when > 30 ng 2nd study fewer relapses | RCT 2,000 IU 10,000 IU RCT |
Pre-term birth | P | 2.5X decrease, also: fewer c-section & better Apgar | RCT 2,000 IU India |
Cluster headaches | T | CH eliminated in 60% | 10,000 IU, Mg, Omega-3, etc |
Autism | T | 80% improved | CT 300 IU/kg/day for 3 months |
PreDiabetes | T | ~20% reduced | RCT 60,000 IU/month |
Weight loss: Overweight and Obese | T | 12 lbs in 6 months | RCT 100,000 IU/month |
Sarcopenia = muscle loss | T | 27% increase | RCT 1,000 IU |
Growing Pains | T | 60% decrease | ~100,000 IU/month -NOT RCT 2nd study, similar results |
Osteoarthritis pain | T | 60% decrease | 50,000 IU/weekly - NOT RCT |
ALS | T | helped | 2,000 IU - NOT RCT, given to all |
Vertigo | T | 3X reduction if raised > 10ng | 600,000 IU load, then maint. NOT RCT, given to all |
Warts | T | 80% eliminated injection | NOT RCT 60,000 IU/injection |
Metabolic Syndrome | P | reduced 44% when VitD increased by 30 ng | NOT RCT, given to all |
Hay fever | P | reduced 48% | RCT 1,000 IU for 30 days |
Preeclampsia | P | Recurrance cut in half 3 RCT 3.6 X less likely if > 30 ng | 50,000 IU every 2 weeks 4,000 IU daily |
Blood cell cancer Multiple Myeloma | T | Survival 90% vs 50% | 10,000 IU/week NOT RCT, given to all |
Irritable Bowel Syndrome | T | Reduced | 3,000 IU spray RCT |
Urinary Tract Infection | P | 50% reduction | RCT 20,000 IU weekly |
Mite Allergy | P | 5X reduction | RCT 2,000 IU preg, 800 IU child |
Perinatal depression (depression near birth) | T | 50% reduction | RCT 2,000 IU for just a few weeks |
Vaginosis | T | 10X reduction | RCT 2,000 IU |
Eczema | T | Reduced | 2 RCT 1,600 IU |
Non-Alcoholic Fatty Liver Disease | T | Reduced | RCT 20,000 IU weekly |
Knee Osteoartiritis | T | Pain Reduced | RCT 60,000 IU monthly after loading dose |
Tuberculosis | T | Faster Recovery | RCT single 450,000 IU dose |
Stroke - Ischemic | T | Faster Recovery | RCT single 600,000 IU injection RCT single 300,000 IU injection |
Sepsis | T | Reduce ICU and Hospital length of stay by 7 days each | RCT 400,000 IU |
Trauma deaths | T | 50% fewer deaths | Vitamin D & Glutamine NOT RCT, given to all |
Hemodialysis patients | T | helped | 50,000 IU weekly NOT RCT, given to all |
Fatty liver - child | T | 2 X reduction | RCT Vitamin D & DHA |
Fatigue | T | Reduced | 100,000 IU single dose NOT RCT, given to all |
Sleep Disorders | T | Nicely treated | RCT 50.000 IU bi-weekly |
Pneumonia (Ventilator-associated) | T | RCT Death rate cut in half | 300,000 IU injection |
Infertile males | T | birth rate doubled | RCT 300,000 IU + maint |
Waist size | T | Waist size reduced 3 cm | 100,000 IU loading + maint for 6 months for those with Metabolic Syndrome NOT RCT, given to all |
Attention Deficient Hyperactivity Disorder | T | Reduced Reduced | RCT 3,000 IU for 12 weeks RCT 50,000 IU weekly |
Alcoholic liver cirrhosis | T | improved survival | 1,000 IU of vitamin D NOT RCT |
Diabetic nephropathy | T | Reduced HOMA-IR, FRS | RCT 50,000 IU weekly |
Ulcerative Colitis | T | Reduced 60% | RCT 50,000 IU nano daily for a week |
Obese weight loss | T | Lost 3X more pounds | $10 of Vitamin D added to calorie restriction & walking |
Endometriosis | T | Nicely treated | RCT 50.000 IU bi-weekly |
Diabetic Wounds | T | 4X more likely to heal | RCT 6,400 daily |
Alzheimer's | T | Often reverse | Each person gets a different amount of Vit D, Omega-3, B12, Iron, etc |
Autoimmune | P | Decrease 30% | RCT Vit D + Omega-3 |
Smoking | T | reduce problems | RCT 50,000 bi-weekly |
Tonsillitis | T | Virtually eliminated | RCT 50,000 weekly |
Epilepsy | T | Helped 6 ways | NOT RCT, given to children & adults |
Dengue Fever | T P | ||
Psoriasis | T | cured | 30,000 to 60,000 IU |
ICU Survival | T | 2X longer | 500,000 IU |
Long-COVID | T | 60,000 IU weekly |
Most proofs are RCT (Randomized Controlled Trials), where not even the doctor knows who gets it vitamin D
- 2 are meta-analyses of multiple RCTs
- Vitamin D was given to ALL infants in the entire country (Rickets) - not an RCT
- In several studies, researchers felt that it was unethical not to give vitamin D to everyone
- In some studies, the dose size varied with the needs of the person (overweight, etc)
- In some studies, the COFACTORS were adjusted to the needs of the patients
- Curing requires the dose size and cofactors to be adjusted to the needs of each patient.
Many Clinical Trials have not found a benefit because of one or more of the following failures:
- Fails to use a large enough dose of vitamin D (often < 1,100 IU)
The Even larger dose needed if: 1) obese, 2) poor gut, 3) sick (many diseases consume lots of vitamin D) - Fails to have given vitamin D for a long enough time (a few RCT lasted less than 5 weeks)
- Fails to have given Vitamin D frequently enough. At least every 2 months for D3) - and at least weekly for D2
Note: Infrequent dosing also causes unbalancing of the body's chemistry - Fails to provide a loading dose, or had too short a duration to restore the vitamin D levels
- Fails to use D3 form, instead uses the less effective D2 form
- Fails to have a healthy range of Calcium or other important cofactors (especially for bone-related trials
Also, differences in Magnesium can result in 30% change in response to vitamin D
Magnesium is dependent on water, food, supplements - Fails to notice the pre-existing vitamin D levels - only those who are low will likely show a benefit
- Fails to notice how/when the vitamin D was taken (which can change the response by as much as 2X)
- Fails to report on compliance (in one case 40% of the participants did not take the supplements consistently)
Many Meta-Analyses also do not find a benefit because one or more of the above failures
In addition, many meta-analysis average together ALL of the trials
Imagine a story about a meta-analysis of aspirin (which has never been done)
There would be scores of RCT for aspirin not working with 3 mg doses
There would be a many RCT of aspirin not working with 30 mg doses
There would be a few studies of aspirin WORKING with 300+ mg doses
There would be many studies of small amounts of Willow bark (Vitamin D2 instead of Vitamin D3)
Then there would be a meta-analysis of aspirin and Willow Bark
- That meta-analysis would conclude that aspirin and Willow bark do not work.
See also VitaminDWiki: Random Controlled Trials with vitamin D intervention
- Intervention - Vitamin D 833 Interventions
- Note: It sorts the interventions by health problem as well as by date
29866 Vitamin D clinical trials as of Jan 2025: Nutrition Disorders 621, Vitamin D Deficiency 619, Malnutrition 601, Avitaminosis 586, Deficiency Diseases 583, Metabolic Diseases 489, Musculoskeletal Diseases 362, Bone Diseases 317. Bone Diseases, Metabolic 282, Endocrine System Diseases 241. Osteoporosis 209, Immune System Diseases 190, Kidney Diseases 168, Communicable Diseases 164. Infection etc. - Systematic Reviews or Meta-Analysis of Vitamin D 669 items
- 137 health problems associated with low vitamin D – meta-meta-analysis April 2014
- Intervention - 2-30 days 275 items
More intervention trials for Vitamin D than for the TOTAL of Vitamins A + C + K combined
Vitamin D = 2199, Others = 1803 Vitamin A 702 + Vitamin C 768 + Vitamin K 333 as of Aug 2020
See also VitaminDWiki
- Overview: Vitamin D also TREATS
- Is it ethical to not give vitamin D in osteoporosis trials– NEJM Sept 2010
- Some Vitamin D RCT are not being created because the researchers do not want to deprive the benefits to half of the patients
- Some Vitamin D RCT cannot be started because too many candidates are already taking vitamin D
- Reasons for Vitamin D deficiency
- List of all categories of Vitamin D Information and number of items in each
- List of all Overviews of Vitamin D 69 items along with related searches
CLICK ON chart for more information and translation
Vitamin D is especially needed during pregnancy
Most were taking 2,000 to 7,000 IU daily for >50% of pregnancy
Click on hyperlinks for details
Problem | Vit. D Reduces | Evidence | |
0. Chance of not conceiving | 3.4 times | Observe | |
1. Miscarriage | 2.5 times | Observe | |
2. Pre-eclampsia | 3.6 times | RCT | |
3. Gestational Diabetes | 3 times | RCT | |
4. Good 2nd trimester sleep quality | 3.5 times | Observe | |
5. Premature birth | 2 times | RCT | |
6. C-section - unplanned | 1.6 times | Observe | |
Stillbirth - OMEGA-3 | 4 times | RCT - Omega-3 | |
7. Depression AFTER pregnancy | 1.4 times | RCT | |
8. Small for Gestational Age | 1.6 times | meta-analysis | |
9. Infant height, weight, head size within normal limits | RCT | ||
10. Childhood Wheezing | 1.3 times | RCT | |
11. Additional child is Autistic | 4 times | Intervention | |
12.Young adult Multiple Sclerosis | 1.9 times | Observe | |
13. Preeclampsia in young adult | 3.5 times | RCT | |
14. Good motor skills @ age 3 | 1.4 times | Observe | |
15. Childhood Mite allergy | 5 times | RCT | |
16. Childhood Respiratory Tract visits | 2.5 times | RCT |
RCT = Randomized Controlled Trial
Also, The Vitamin D Receptor limits the amount of Vitamin D in the blood actually gets to the tissue
The risk of 48+ diseases at least double with poor Vitamin D Receptor
Short URL = is.gd/dproof
There are 436 items with RCT in the title on VitaminDWiki as of May 2017
38 Reasons why there can be a low response to Vitamin D
Many of the reasons are not considered by most Vitamin D RCTs
Reasons for low response to vitamin D
RCTS are the only appropriate way to demonstrate the role of vitamin D in health – May 2017
The Journal of Steroid Biochemistry and Molecular Biology, online 5 May 2017, https://doi.org/10.1016/j.jsbmb.2017.05.004
Rolf Jordea, b, rolf.jorde@unn.no
Despite thousands of vitamin D studies published, including hundreds of reviews and meta-analyses, it is still uncertain if supplementation with vitamin D will have positive health effects, except for the skeleton. This cannot be answered by doing more observational studies as it is impossible to control for confounding factors and reverse causality.
The only way to firmly prove positive vitamin D effects is by doing the properly designed randomized controlled trials (RCTs).
However, it has been difficult to show the expected positive effects by vitamin D supplementation in RCTs, which may indicate that the effects, if present must be small.
On the other hand, results from Mendelian randomization studies have shown promising results at least for mortality and multiple sclerosis. In the near future, results from several large RCTs with hard endpoints will be available.
If these show positive results, the main question on vitamin D and health is answered.
If they turn out negative, they will be criticized for having included subjects without vitamin D deficiency, and some studies might not have used an optimal dosing regimen. New and better-designed RCTs will then be needed, but will be very hard to perform.
Publisher wants $36 for the PDF
Those perceiving problems with vitamin D were 20X more likely to not participate in an RCT - July 2016
Often problems are due to low Magnesium
Randomized controlled trials: who fails run-in? - July 2016
Trials. 2016 Jul 29;17:374. doi: 10.1186/s13063-016-1451-9.
Rees JR1, Mott LA1, Barry EL1, Baron JA1,2, Figueiredo JC3, Robertson DJ4, Bresalier RS5, Peacock JL6,7.
BACKGROUND:
Early identification of participants at risk of run-in failure (RIF) may present opportunities to improve trial efficiency and generalizability.
METHODS:
We conducted a partial factorial-design, randomized, controlled trial of calcium and vitamin D to prevent colorectal adenoma recurrence at 11 centers in the United States. At baseline, participants completed two self-administered questionnaires (SAQs) and a questionnaire administered by staff. Participants in the full factorial randomization (calcium, vitamin D, both, or neither) received a placebo during a 3-month single-blinded run-in; women electing to take calcium enrolled in a two-group randomization (calcium with vitamin D, or calcium alone) and received calcium during the run-in. Using logistic regression models, we examined baseline factors associated with RIF in three subgroups: men (N = 1606) and women (N = 301) in the full factorial randomization and women in the two-group randomization (N = 666).
RESULTS:
Overall, 314/2573 (12 %) participants failed run-in; 211 (67 %) took fewer than 80 % of their tablets (poor adherence), and 103 (33 %) withdrew or were uncooperative. In multivariable models, 8- to 13-fold variation was seen by study center in odds of RIF risk in the two largest groups. In men, RIF decreased with age (adjusted odds ratio [OR] per 5 years 0.85 [95 % confidence interval, CI; 0.76-0.96]) and was associated with being single (OR 1.65 [95 % CI; 1.10-2.47]), not graduating from high school (OR 2.77 [95 % CI; 1.58-4.85]), and missing SAQ data (OR 1.97 [1.40-2.76]). Among women, RIF was associated primarily with health-related factors; RIF risk was lower with higher physical health score (OR 0.73 [95 % CI; 0.62-0.86]) and baseline multivitamin use (OR 0.44 [95 % CI; 0.26-0.75]). Women in the 5-year colonoscopy surveillance interval were at greater risk of RIF than those with 3-year follow-up (OR 1.91 [95 % CI; 1.08-3.37]), and the number of prescription medicines taken was also positively correlated with RIF (p = 0.03).
Perceived toxicities during run-in were associated with 12- to 29-fold significantly increased odds of RIF.
CONCLUSIONS:
There were few common baseline predictors of run-in failure in the three randomization groups. However, heterogeneity in run-in failure associated with study center, and missing SAQ data reflect potential opportunities for intervention to improve trial efficiency and retention.
TRIAL REGISTRATION: ClinicalTrials.gov: NCT00153816 . Registered September 2005.
PMID: 27474021 PMCID: PMC4966775 DOI: 10.1186/s13063-016-1451-9
Download the PDF from VitaminDWiki
32% of Breast Cancer patients in an RCT failed to consistent take DAILY vitamin D - July 2016
- Impact of a tailored oral vitamin D supplementation regimen on serum 25-hydroxyvitamin D levels in early breast cancer patients: a randomized phase III study
Much better compliance in the trial which was taking weekly doses
Free full text is on-line
Vitamin D – wait for Random Controlled Trials, rebuttal – not wait and consider UV – Feb 2015
Vitamin D clinical trials should be based on Vitamin D tests – Aug 2017
Founder of VitaminDWiki is a co-author of the paper
How to Understand, Refute, and Plan Studies Using Vitamin D - Vaseuez 2017
Excellent
Download the PDF from VitaminDWiki
- "“This insight also illuminates a double-standard in research: whereas no legitimate drug study would use a subtherapeutic dose of a pharmaceutical agent and then (falsely) assert inefficacy,poorly designed and therapeutically underpowered (eg, using 10% of the known effective dose) nutrition studies are published and make headlines and shape policy (mostly by maintaining the status quo of nutritional inaction and ignorance) on weekly basis. "
- "For example, a study using an antibiotic or antiseizure drug that failed to administer a therapeutic dosage or achieve a therapeutic serum level would never be accepted for publication in a headlining medical journal; yet, underdosed nutrition studies are commonly published in headlining journals and then reported to mainstream media as proof of the inefficacy of nutritional intervention.”
How to Critique Vitamin D Studies—A Checklist
1. Did the study subjects receive at least 4,000-10,000 IU per day? .
2. Is the duration of the study at least 6-9 months?
3. Did the study use vitamin D3 (cholecalciferol) rather than fungally-derived erogcalciferol?
4. Was the product validated for potency?
5. Were serum 25-OH-vitamin D levels measured?
6. Did serum 25-OH-vitamin D levels enter the optimal range at least 2-6 months before the end of the study?
7. Were the patients deficient at the start of the study and then robustly replaced with vitamin D?
8. Vitamin D supplementation should be stopped for roughly 20-30 days before serum testing because 25-hydroxyvitamin D3 (calcidiol) has a half-life of 15
days.