2017 study by Martineau et al in The British Medical Journal
In 2017, the study of A. Martineau et al. appeared in the British Medical Journal, under the title “Vitamin D supplementation to prevent acute respiratory tract infections.” The study looks at data from 25 studies, randomised and placebo-controlled, on almost 11,000 subjects aged 0 to 95 years. Conclusions: "Vitamin D supplementation was safe and it protected against acute respiratory infections overall.” Vitamin D supplements lower viral replication rates, reduce inflammation, stimulate the immune system, and result in infections decreasing by 70%, for those who were very D-deficient, at a level below 10 ng/ml. Such success is lacking when vitamin D is given in bolus form, in large monthly doses. https://www.bmj.com/content/356/bmj.i6583
Acute respiratory tract infections are a major cause of global morbidity and mortality and are responsible for 10% of ambulatory and emergency department visits in the USA1 and an estimated 2.65 million deaths worldwide in 2013.2 Observational studies report consistent independent associations between low serum concentrations of 25-hydroxyvitamin D (the major circulating vitamin D metabolite) and susceptibility to acute respiratory tract infection.34
... Treatment with large boluses of vitamin D has been associated with reduced efficacy for non-classic effects,9 and in some cases an increased risk of adverse outcomes.19. ...vitamin D supplementation reduced the risk of experiencing at least one acute respiratory tract infection. .. Use of vitamin D was safe: potential adverse reactions were rare, and the risk of such events was the same between participants randomised to intervention and control arms.
Why might use of bolus dose vitamin D [single dose of 100-200,000 IU] be ineffective for prevention of acute respiratory tract infection? One explanation relates to the potentially adverse effects of wide fluctuations in circulating 25-hydroxyvitamin D concentrations, which are seen after use of bolus doses but not with daily or weekly supplementation. Vieth has proposed that high circulating concentrations after bolus dosing may chronically dysregulate activity of enzymes responsible for synthesis and degradation of the active vitamin D metabolite 1,25-dihydroxyvitamin D, resulting in decreased concentrations of this metabolite in extra-renal tissues.38
Conclusions and policy implications
Our study reports a major new indication for vitamin D supplementation: the prevention of acute respiratory tract infection. We also show that people who are very deficient in vitamin D and those receiving daily or weekly supplementation without additional bolus doses experienced particular benefit. Our results add to the body of evidence supporting the introduction of public health measures such as food fortification to improve vitamin D status, particularly in settings where profound vitamin D deficiency is common.
https://www.bmj.com/content/356/bmj.i6583
Vitamin D deficiency, or hypovitaminosis D is defined as a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate sunlight exposure (in particular sunlight with adequate ultraviolet B rays (UVB)).[1][2][3] Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D, disorders limiting vitamin D absorption, and conditions impairing vitamin D conversion into active metabolites—including certain liver, kidney, and hereditary disorders.[4] Deficiency impairs bone mineralization, leading to bone softening diseases such as rickets in children. It can also worsen osteomalacia and osteoporosis in adults, leading to an increased risk of bone fractures.[1][4] Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of fall and bone fractures in adults.[1] Vitamin D deficiency is associated with the development of schizophrenia.[5]
Guidelines on prevention and treatment of vitamin D deficiency
Both vitamin D3 and vitamin D2 can derive from the diet, but the predominant share of vitamin D3 comes from the conversion of 7-dehydrocholesterol (or provitamin D) following skin exposure to ultraviolet rays of specific wavelength (UVB between 290 and 315 nm).
Such UVB radiation is present in sunlight only for a limited number of hours, which varies depending on the season and latitude. For this reason, in Italy, the production of vitamin D linked to sun exposure is negligible in the winter months. Other factors that strongly influence vitamin synthesis are age (for the same amount of sun exposure the elderly person produces 30% less), the surface and thickness of the skin exposed to the sun, the time of irradiation, as well as the use of protective creams, which can reduce skin synthesis of vitamin D by 97%.
At temperate latitudes, 80% of the vitamin D requirement is guaranteed by solar irradiation and the remaining 20% is ensured by nutrition. Vitamin D3 is contained almost exclusively in animal fats, while the share of vitamin D2 present in some vegetable fats is negligible... https://pubmed.ncbi.nlm.nih.gov/22257914/
Treatment[edit]
In the United States and Canada as of 2016, the amount of vitamin D recommended is 400 IU per day for children, 600 IU per day for adults, and 800 IU per day for people over age 70.[54][55]
Coronavirus (COVID-19) update
If you're still spending more time indoors than usual this spring and summer, you should take 10 micrograms (400 IU) of vitamin D a day to keep your bones and muscles healthy. There have been some reports about vitamin D reducing the risk of coronavirus (COVID-19). But there is currently not enough evidence to support taking vitamin D solely to prevent or treat COVID-19. https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
Overwhelming evidence that vitamin D prevents respiratory infections and is safe. It is not rational to suggest that vitamin D may not prevent Covid-19. It is even less rational to claim that Vitamin D does not prevent Covid-19. This last claim, made by the Italian Health Ministry can be deemed murderous in its effect.
How much vitamin D do I need?
The amount of vitamin D you need each day depends on your age. Average daily recommended amounts are listed below in micrograms (mcg) and International Units (IU):
| Life Stage | Recommended Amount |
|---|---|
| Birth to 12 months | 10 mcg (400 IU) |
| Children 1–13 years | 15 mcg (600 IU) |
| Teens 14–18 years | 15 mcg (600 IU) |
| Adults 19–70 years | 15 mcg (600 IU) |
| Adults 71 years and older | 20 mcg (800 IU) |
| Pregnant and breastfeeding teens and women | 15 mcg (600 IU) |
https://ods.od.nih.gov/factsheets/VitaminD-Consumer/
As for the amount suggested by NIAID, please see Fauci Anthony.
How much D to advise is a difficult decision to make. Unless it's an easy decision to make. To issue an honest vitamin D advisory would be harmful to the interests of any WHO bureaucrat or minister of health in any important country, who counts on a successful retirement on a Big Pharma board of directors.
The leaders at the World Health Organization ("WHO") have been thinking about it for years; they are still thinking about it. In 2011, WHO doctors published a paper under the title "Vitamin D supplementation and respiratory infections in children". They added some thirty studies on the effects of the D. The large dose studies, giving 100-200,000 IU in one dose, showed no positive results, confirming the conclusions of Martineau.
"Future studies, however, need to be undertaken in different settings to confirm these results, especially among populations of children who are not classified as vitamin D deficient living in high-resource settings. Children in more northern latitudes lacking sun exposure, and dark-skinned children, are most at risk of vitamin D deficiency and of developing more severe forms of acute lower respiratory infections. However, cut-off values for vitamin D sufficiency and recommended daily intake in children are still under debate." https://www.who.int/elena/titles/bbc/vitamind_pneumonia_children/en/
The WHO doctors did not appear pleased abut the inertia of the WHO leadership and about the bickering between competing medical societies
The Canadian Paediatric Society recommends that pregnant or breastfeeding women consider taking 2000 IU/day, that all babies who are exclusively breastfed receive a supplement of 400 IU/day, and that babies living north of 55°N get 800 IU/day from October to April.[56]
NIH, as you can see above, recommends 600 IU for breastfeeding women.
Another opinion, from from Hollis and Wagner 2004, in the American Journal of Clinical Nutrition.
Scientific data pertaining to vitamin D supplementation during lactation are scarce. The daily recommended intake for vitamin D during lactation has been arbitrarily set at 400 IU/d (10 microg/d). This recommendation is irrelevant with respect to maintaining the nutritional vitamin D status of mothers and nursing infants, especially among darkly pigmented individuals. Our objective was to examine the effect of high-dose maternal vitamin D2 supplementation on the nutritional vitamin D status of mothers and nursing infants...
With limited sun exposure, an intake of 400 IU/d vitamin D would not sustain circulating 25(OH)D concentrations and thus would supply only limited amounts of vitamin D to nursing infants in breast milk. A maternal intake of 2000 IU/d vitamin D would elevate circulating 25(OH)D concentrations for both mothers and nursing infants, albeit with limited capacity, especially with respect to nursing infants. A maternal intake of 4000 IU/d could achieve substantial progress toward improving both maternal and neonatal nutritional vitamin D status. https://pubmed.ncbi.nlm.nih.gov/15585800/
The lower the 25(OH)D serum concentration is before treatment, the higher is the dosage that is needed in order to quickly reach an acceptable serum level.[57]
The initial high-dosage treatment can be given on a daily or weekly basis or can be given in form of one or several single doses (also known as stoss therapy, from the German word Stoß 'push').[58]
As discussed above by Martineau, bolus therapy, in which 100,000 or 200,000 IU are taken, appears to be ineffective,
Research[edit]
Some evidence suggests vitamin D deficiency may be associated with a worse outcome for some cancers, but evidence is insufficient to recommend that vitamin D be prescribed for people with cancer.[83] Taking vitamin D supplements has no significant effect on cancer risk.[84] Vitamin D3, however, appears to decrease the risk of death from cancer but concerns with the quality of the data exist.[85]
Vitamin D deficiency is thought to play a role in the pathogenesis of non-alcoholic fatty liver disease.[86][87]
Evidence suggests that vitamin D deficiency may be associated with impaired immune function.[88] Those with vitamin D deficiency may have trouble fighting off certain types of infections. It has also been thought to correlate with cardiovascular disease, type 1 diabetes, type 2 diabetes, and some cancers.[7]
Review studies have also seen associations between vitamin D deficiency and pre-eclampsia.[89]
Some of the good motives for delaying any decision on vitamin D.