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Limits of Vitamin D Supplements
By NICHOLAS BAKALAR

A large review of studies has found that vitamin D supplements have little or no benefit beyond the low levels required for bone health.

low vitamin D levels are almost surely an effect of these diseases, and not a cause.

The meta-analysis, published in The Lancet Diabetes & Endocrinology, combined data from 290 observational studies and 172 random trials.
All the studies used blood levels of vitamin D to measure outcomes. Dosages varied, but most trials used 800 units or more.

The observational studies generally found an association of lower vitamin D levels with increases in cardiovascular disease, lipid concentrations, glucose levels, weight gain, infectious disease and mood disorders.
But random trials showed little or no effect of vitamin D supplements on any of these problems.
The authors conclude that low vitamin D levels are almost surely an effect of these diseases, and not a cause.

Current guidelines recommend supplements for anyone with a blood level under 30 nanograms per milliliter, but the lead author, Dr. Philippe Autier, said that only at levels of 10 or less would there be a risk to skeletal health.
Less than 10 percent of Americans, he estimates, fall into this category.
Dr. Autier is a researcher at the International Prevention Research Institute in Lyon, France.

“Unfortunately, there is probably no benefit to expect from vitamin D supplementation in normally healthy people,” he said.

Verder lezen:
http://www.thelancet.com/journals/landi ... 7/abstract

Vitamin D status and ill health: a systematic review
Prof Philippe Autier MD a b Corresponding AuthorEmail Address, Prof Mathieu Boniol PhD a b, Cécile Pizot MSc a, Prof Patrick Mullie PhD a c
Summary
Low serum concentrations of 25-hydroxyvitamin D (25[OH]D) have been associated with many non-skeletal disorders. However, whether low 25(OH)D is the cause or result of ill health is not known. We did a systematic search of prospective and intervention studies that assessed the effect of 25(OH)D concentrations on non-skeletal health outcomes in individuals aged 18 years or older. We identified 290 prospective cohort studies (279 on disease occurrence or mortality, and 11 on cancer characteristics or survival), and 172 randomised trials of major health outcomes and of physiological parameters related to disease risk or inflammatory status. Investigators of most prospective studies reported moderate to strong inverse associations between 25(OH)D concentrations and cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High 25(OH)D concentrations were not associated with a lower risk of cancer, except colorectal cancer. Results from intervention studies did not show an effect of vitamin D supplementation on disease occurrence, including colorectal cancer. In 34 intervention studies including 2805 individuals with mean 25(OH)D concentration lower than 50 nmol/L at baseline supplementation with 50 μg per day or more did not show better results. Supplementation in elderly people (mainly women) with 20 μg vitamin D per day seemed to slightly reduce all-cause mortality. The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health. Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D, which would explain why low vitamin D status is reported in a wide range of disorders. In elderly people, restoration of vitamin D deficits due to ageing and lifestyle changes induced by ill health could explain why low-dose supplementation leads to slight gains in survival.

Als je een studie ziet met een uitkomst waarvan je denkt: dat kan toch haast niet, dan is er meestal ook echt iets mis.

Zo ook in dit geval. De onderzoekers zijn bijvoorbeeld deze studie, naar het effect van vitamine D op de ontwikkeling van MS, vergeten mee te nemen:
http://www.ncbi.nlm.nih.gov/pubmed/23250818. Laat dat nu net een studie zijn waaruit wél een significante causale relatie tussen het verhogen van de vitamine D-spiegel en een minder snelle ontwikkeling van MS naar voren komt.

De komende tijd zullen er ongetwijfeld uitgebreide reacties op deze studie verschijnen.

hallo Prutser,

Het artikel waarnaar je verwijst bij Kennis en info, is gebaseerd op dit onderzoek: http://www.ncbi.nlm.nih.gov/pubmed/24320141

De conclusie luidt: The level of serum vitamin D was significantly lower in pre-menopausal women with AITD. Vitamin D deficiency and insufficiency were significantly associated with AITD in pre-menopausal women.
Of iemand AITD had werd bepaald aan de hand van TPO-Ab en echo's.

Het lijkt er veel op dat de conclusie bevestigt van het Lancet-onderzoek: laag vitamine D is gevolg van kwalen en niet de oorzaak.

Dank suze, ik had die Pubmed-publicatie nog niet gezien.

Voor zover ik kan zien is het puur een associatieonderzoek en doen de onderzoekers geen uitspraken over eventuele causale verbanden. Ik zou zeggen dat de bevindingen noch een bevestiging, noch in tegenspraak zijn met de conclusies van het Lancet-onderzoek.

In viewtopic.php?f=21&t=2644 noem je deze bron: http://www.vitamindcouncil.org/vitamin- ... d-disease/

Onder dat artikel van Vitamin D Council staat deze bron: http://www.ncbi.nlm.nih.gov/pubmed/24320141
Het zegt inderdaad weinig over oorzaak en gevolg.

Ik heb op het Vit.D forum onderstaand vermeld
(2 in 1 artikel in The Lancet van 6 dec. j.l.)



NB Zijn volledige artikelen !
Downloaden - Zie de link helemaal onderaan.



Hier een stukje
Conclusions
Many prospective studies have shown associations between low 25(OH)D concentrations and a wide range of acute and chronic health disorders.
However, an equally similar number of randomised trials have not confirmed that raising of 25(OH)D concentrations can
modify the occurrence or clinical course of these disorders.
Hence, associations between 25(OH)D and health disorders reported by investigators of observational studies are not causal.

Low 25(OH)D could be the result of inflammatory processes involved in the occurrence and progression of disease.

An exception would be slight gains in survival after the restoration of vitamin D deficits due to lifestyle changes induced by ageing and ill health.

Five trials including 2150–20 000 patients aged 50 years or older are in progress, testing whether vitamin D supplementation at
40–80 ?g per day can reduce the risk of cancer, cardiovascular diseases, diabetes, infections, declining cognitive functions, and fractures.63
The first results are not expected before 2017, but these studies have the potential to test our hypotheses.


Zie verder de volledige artikelen op Vit. D forum:
http://www.vitamined-forum.nl/index.php ... 769.0.html