Vitamine D: wetenschap

Alles omtrent voeding en supplementen
neuron
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Bloed en Genen test

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Bloed en Genen test

Klick,

Je zou zomaar eens gelijk kunnen hebben.

Naast bloedtesten, zou het wenselijk zijn om onze Vitamine D genen eens te laten testen.

Zo'n test bestaat er bij mijn weten nog niet voor MS.

Er is zo langzaam aan opgeteld echt genoeg bewijs dat vitamine D op de een of andere manier te maken heeft met MS.

Alleen sommige neurologen willen er nog steeds niet aan.

.
neuron
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Vitamine D genen en MS

Bericht door neuron »

Vitamine D genen en MS

Bewijs

Een vitamine D-tekort kan mede worden veroorzaakt door je genen, waardoor het risico op MS groter is.

[B]Low-Frequency Synonymous Coding Variation in CYP2R1 Has Large Effects on Vitamin D Levels and Risk of Multiple Sclerosis[/B]

[QUOTE]Vitamin D insufficiency is common, correctable, and influenced by genetic factors, and it has been associated with risk of several diseases. We sought to identify low-frequency genetic variants that strongly increase the risk of vitamin D insufficiency and tested their effect on risk of multiple sclerosis, a disease influenced by low vitamin D concentrations. We used whole-genome sequencing data from 2,619 individuals through the UK10K program and deep-imputation data from 39,655 individuals genotyped genome-wide. Meta-analysis of the summary statistics from 19 cohorts identified in CYP2R1 the low-frequency (minor allele frequency = 2.5%) synonymous coding variant g.14900931G>A (p.Asp120Asp) (rs117913124[A]), which conferred a large effect on 25-hydroxyvitamin D (25OHD) levels (−0.43 SD of standardized natural log-transformed 25OHD per A allele; p value = 1.5 × 10−88). The effect on 25OHD was four times larger and independent of the effect of a previously described common variant near CYP2R1. By analyzing 8,711 individuals, we showed that heterozygote carriers of this low-frequency variant have an increased risk of vitamin D insufficiency (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.78–2.78, p = 1.26 × 10−12). Individuals carrying one copy of this variant also had increased odds of multiple sclerosis (OR = 1.4, 95% CI = 1.19–1.64, p = 2.63 × 10−5) in a sample of 5,927 case and 5,599 control subjects. In conclusion, we describe a low-frequency CYP2R1 coding variant that exerts the largest effect upon 25OHD levels identified to date in the general European population and implicates vitamin D in the etiology of multiple sclerosis.[/QUOTE]

DOI: [url]http://dx.doi.org/10.1016/j.ajhg.2017.06.014[/url]

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MarcC
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Bericht door MarcC »

Tja, niet een heel makkelijk stuk om te lezen.

Als ik het goed begrijp, dan heb je met een bepaalde genenvariant (heterozygoot, dus 2 verschillende genexpressies voor dezelfde eigenschap) een verhoogd risico op vitamine D tekort (je maakt gewoon minder actieve vitamine D aan, te corrigeren door veel meer vitamine D te slikken). Toevallig heb je met die genenvariant ook een verhoogd risico op MS. MS en laag vitamine D zijn dus wel gelinkt, maar ik denk niet dat je op basis van DIT onderzoek kunt stellen dat door een laag vitamine D gehalte het risico op MS wordt vergroot. Ze komen toevallig vaker bij elkaar voor, maar het is geen oorzaak-gevolg.

Gelukkig zijn er wel andere studies die aantonen dat een voldoende hoog vitamine D gehalte (bij mensen met MS dus veel hoger gezien het voorgaande) een positieve invloed kan hebben op MS.

Groetjes, Marc
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Klick
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@marcC jouw uitleg kan ik volgen 👍het stuk over het onderzoek trekt mijn hoofd niet momenteel...😐
MarcC
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Bericht door MarcC »

[QUOTE=Klick;1091732]@marcC jouw uitleg kan ik volgen ��het stuk over het onderzoek trekt mijn hoofd niet momenteel...��[/QUOTE]

Bedenk wel dat mijn uitleg niet juist hoeft te zijn. Het is wat ik denk dat er staat in lastig stuk tekst met veel moeilijke woorden. Misschien sla ik de plank wel helemaal mis :???:

groetjes, Marc
neuron
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het CYP2R1 gen

Bericht door neuron »

het CYP2R1 gen

MarcC,

Wat je schrijft klopt.

Het gen CYP2R1 codeert voor het enzym [B]vitamine D 25-hydroxylase[/B]. Dit enzym zet vitamine D3 om in 25OHD.

Uit dit onderzoek blijkt dat als dit gen een typfout (SNP) in het DNA heeft waardoor het enzym vitamine D3 niet (goed) in 25OHD kan omzetten heeft dit een lager vitamine D gehalte tot gevolg.

Een lager vitamine D-gehalte kan vele oorzaken hebben dit is er dus een van.

[B]Oorzaken van een lager vitamine D-gehalte[/B]
1-te weinig zonlicht,
2-winter,
3-geen vitamine D3 in de voeding,
4-te dik,
5-roken,
6-genen die belangrijk zijn bij de vitamine D stofwisseling in je lijf. Het belangrijkste gen is waarschijnlijk CYP2R1, maar er zijn er meer

Uit dit onderzoek blijkt ook dat mensen met MS vaker een typfout in het CYP2R1 gen hebben dan de mensen zonder MS.

.
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Klick
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daar hou ik rekening mee :p
Marsei
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Lid geworden op: 22 jan 2010, 22:00

Low Vitamin D Levels Linked with MS Risk

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Low Vitamin D Levels Linked with MS Risk

[URL="http://www.medpagetoday.com/neurology/m ... osis/67897"][U]Low Vitamin D Levels[/U][/URL] [URL="http://www.medpagetoday.com/neurology/m ... osis/67897"][U]Linked with MS Risk[/U][/URL]
Supplementation may help reduce the elevated risk
Marsei
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More Evidence Links Vitamin D Deficiency to MS

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More Evidence Links Vitamin D Deficiency to MS

Van Ashton Embry op FB:

[QUOTE]More Evidence Links Vitamin D Deficiency to MS
Pauline Anderson

September 14, 2017
Results of a large new study reinforce the view that vitamin D deficiency may be a risk factor for multiple sclerosis (MS).

The study, which compared vitamin D levels in blood donated by pregnant women without MS, showed a twofold increase in MS risk among those considered vitamin D deficient compared with those who had adequate levels.

While numerous previous studies have shown similar findings, this was the largest longitudinal investigation yet to directly assess whether vitamin D levels in healthy individuals predict their risk for MS.
"Previous studies had fewer than 20 MS cases, and here we had over 1000 women with MS, so it was a very large study," lead author, Kassandra L, Munger, ScD, research scientist, Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, told Medscape Medical News.

The study was published online September 13 in Neurology.
Dr Munger and her colleagues used the Finnish Maternity Cohort, which comprises over 800,000 women who have provided a blood sample for routine prenatal testing, typically between 10 and 14 weeks' gestation. There are over 1.8 million stored serum samples, covering over 95% of pregnancies in Finland since 1983.
In 2004, Finland formally recommended that pregnant women take vitamin D supplements.

Using linked national databases, researchers identified women with a sample who were subsequently diagnosed with MS. On average, serum samples were collected 9.3 years before the MS diagnosis.
The analysis included 6200 serum samples from 1092 cases as well as 2123 age- and residence-matched controls.

Vitamin D Deficiency
For the study, researchers defined vitamin D deficiency as levels of 25-hydroxyvitamin D (25[OH]D) less than 30 nmol/L. Insufficient levels were 30 to less than 50 nmol/L, and adequate levels were 50 nmol/L or greater.
Women in the study collectively had relatively high levels of vitamin D deficiency and insufficiency, said Dr Munger. This may be because Finns, living in a northern hemisphere, historically have had low vitamin D levels. Also, the Finnish Maternity Cohort dates back to 1983, before many of the recommendations surrounding prenatal vitamins came into play.

Multivariate-adjusted analyses showed that a 50-nmol/L increase in 25(OH)D was associated with a 39% reduced risk for MS (relative risk [RR], 0.61; 95% confidence interval [CI], 0.44 - 0.85; P = .003, adjusted for gravidity, parity, and time of sample collection).
Compared with women with adequate vitamin D levels, those with deficient levels had a 43% increased risk for MS. Compared with women with insufficient levels, those who were deficient had a 27% increased MS risk (adjusted RR, 1.27; 95% CI, 1.07 - 1.50, P = .005).

In an analysis of quintiles, women in the bottom two quintiles (<26.8 nmol/L or extreme deficiency) had a 53% to 66% increased risk for MS compared with women in the top quintile (41 nmol/L or greater). The overall trend of increasing MS risk with decreasing 25(OH)D was statistically significant.

The researchers also looked at the association between vitamin D levels and MS risk in 511 MS cases and 831 matched controls who had two or more serum samples. Such an analysis should be less affected by random variation than that based on a single measurement, the researchers note.

The association here was even stronger; there was a two-fold higher risk for MS in women with 25(OH)D less than 30 nmol/L compared with women with levels 50 nmol/L or greater (RR, 2.02; 95% CI, 1.18 - 3.45; P = .01).

Because the serum samples were collected nearly a decade before the MS diagnosis, reverse causation as an explanation of the results was reduced, the authors write.

A limitation of the study was that it could not adjust for other MS risk factors, such as smoking, body mass index in adolescence or early adulthood (a relatively newly uncovered possible risk factor), human leukocyte antigen status (a possible genetic risk factor), and Epstein-Barr virus infection. As well, the study included mostly white participants.

Although the current study included only women, the authors noted that previous research found decreased MS risk with increasing 25(OH)D levels in both men and women.
The women in the current study "just happened to be pregnant," commented Dr Munger. "It was a cohort that we could access; pregnancy itself is kind of irrelevant in this study."

Despite the accumulating research, it's still not clear what the optimal vitamin D level is to prevent MS.
"We still don't have a good handle on the best time — and if there is a best time — for people to supplement with vitamin D to reduce MS risk, or the actual dose, or level that is most beneficial," said Dr Munger.

"Studies are indicating that it seems that the more vitamin D you can get, the lower your risk seems to go, but we haven't identified a threshold level yet."
She noted that researchers have not been able to look much beyond the 100 nmol/L level. In this study, only 15 participants had vitamin D levels above 75 nmol/L, she said.

Time for Active Prevention?
In an editorial accompanying the publication, Ruth Ann Marrie, MD, PhD, University of Manitoba, Winnipeg, Canada, and Christopher A. Beck, PhD, University of Rochester Medical Center, New York, explore the question of whether, based on this study and other evidence, it is time to undertake more active prevention of MS.
"Overall, this study adds to the biologic data and epidemiologic body of evidence supporting a causal role for vitamin D in MS," they write.
"Collectively, 3 studies in adults now show an association between 25(OH)D levels and risk of developing MS years later; the risk appears to be greatest among those with levels in the deficient range, but levels beyond those typically considered sufficient (0.99 nmol/L) may exert protective effects."

They go on to weigh the pros and cons of undertaking a universal recommendation for vitamin D supplementation as a public health strategy to prevent MS. In terms of limitations, they point out that first, most of the available studies are in white populations from Europe and the United States, so "studies conducted in other racial groups and in other regions are needed."

"Second, it is uncertain whether supplementation would be needed lifelong or whether supplementation during a critical period would be adequate," Dr Marrie and Dr Beck write.

"Third, we lack evidence from a randomized controlled trial. However, such a trial would not be feasible due to the need for large samples, long duration of follow-up, and costs."

Conversely, they examine the potential benefits of going ahead now with a strategy of vitamin D supplementation.
"Vitamin D supplementation is a simple intervention that would be highly cost-effective even if it prevents only a proportion of MS cases," they write. "Harm from such a strategy is unlikely; doses of up to 4,000 IU/day are safe for adults even in pregnancy, so they could be used through late adolescence and adulthood as such doses would be adequate to achieve vitamin D sufficiency in most individuals."

It may also produce other benefits; they note; for example, supplementation during infancy has been shown to be associated with greater bone mass among girls aged seven to nine years.
"It is time to take an active approach to preventing MS, at a minimum targeting those individuals with an elevated risk of MS, including smokers, the obese, and those with a family history of MS," they conclude.

Commenting on the study for Medscape Medial News, Lily Jung Henson, MD, chief of neurology, Piedmont Healthcare, Atlanta, Georgia, said it "nicely lends support" to prior studies showing that elevated vitamin D levels were associated with a reduction of MS risk.

Dr Jung Henson noted that the study also suggests that vitamin D replenishment in reproductive-age women may be beneficial in reducing the risk for MS.
"This has implications in those who may be at higher risk of developing the disease."[/QUOTE]
Marsei
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Lid geworden op: 22 jan 2010, 22:00

The role of vitamin D in MS

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The role of vitamin D in MS

[URL="https://www.ncbi.nlm.nih.gov/m/pubmed/2 ... +sclerosis"][U]The role of vitamin D in multiple sclerosis[/U][/URL]: biology & biochemistry, epidemiology and potential roles in treatment

[QUOTE][B]Abstract[/B]
Multiple sclerosis (MS) is a progressive, demyelinating condition of the central nervous system, manifesting in loss or alterations in function of sensory, motor and cognitive function. Of the various environmental and behavioural risk factors identified as playing a role in MS onset and progression, perhaps none has been as consistent as vitamin D.

[B]OBJECTIVE[/B]: In this review, we will endeavour to present a general background on the role of vitamin D in human health and particularly in MS, as well as the substantial epidemiological evidence in support of vitamin D's role in MS.

[B]RESULTS[/B]: Identified initially indirectly via the oft-noted latitudinal gradient in MS prevalence and incidence, vitamin D has since been demonstrated to have a strong and consistent inverse association with MS risk and clinical course.

Cases have much lower levels of the diagnostic metabolite of vitamin D, 25-hydroxyvitamin D (25(OH)D) compared to healthy controls, while those with more active disease have lower levels of 25(OH)D than other cases with less active disease.

These case-control and cross-sectional study results led the way to cohort studies which indicated significant inverse associations between serum 25(OH)D and clinical activity in MS. The combined weight of indirect and direct observational evidence have been the impetus for completed and ongoing randomised trials of vitamin D supplementation, alone or in addition to standard immunomodulatory medications, as an intervention in MS onset and clinical course.

Moreover, in addition to being a distinct factor in MS aetiology, vitamin D has been demonstrated to interact with a variety of other risk factors, from genetic predictors like HLA-DR1 genotype to behavioural factors like smoking.

[B]CONCLUSION[/B]: There is an abundance of epidemiological evidence, both direct and indirect, as well as significant biological plausibility substantiating a role for vitamin D in the onset & progression of multiple sclerosis.[/QUOTE]
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