...but whatcha' gonna' do?
I think there is something big here and it is staring us in the face. The studies that I just posted are about all there are relating to the relationship between Vit D and GDNF. They all point to a major role. Other studies, including Amgen's notorius work, have made it clear that GDNF is capable of magic if it is in the right place. The studies above indicate a role for Vit D in getting it to that place.
Almost overnight the medical community has gone from saying that 400 IU of Vit D is all we need to saying that some of us may need 1000x that. This tells me that everything needs to be re-examined. The potential here is huge. If a chronic deficiency of Vit D is blocking the natural production of GDNF and the ability to heal ourselves, I want to know.
A lot of PWP have found that they have low Vit D. Have you heard of any of us who reported high levels? Me neither. As Paula mentioned, the general result of GDNF studies has been mixed. But Vit D levels were not considered.
I am going to post an assortment of files for consideration.
In order to keep this readable I am going to use the PubMed ID for citation purposes:
18852350: " RESULTS: Significantly more patients with PD (55%) had insufficient vitamin D than did controls (36%) or patients with AD
(41%"
20625085 : "CONCLUSIONS: The
results are consistent with the suggestion that high vitamin D status provides protection against Parkinson disease."
9371907 : "High prevalence of vitamin D deficiency and reduced bone mass in Parkinson's disease."
20586743 : "Hypovitaminosis D is also associated with several other neurological diseases
that is less likely mediated by dysregulated immune responses, including
Parkinson's disease and Alzheimer's disease, schizophrenia and affective
disorders, suggesting a more diverse role for vitamin D in the maintenance of
brain health. Accordingly, both the vitamin D receptor and the enzymes necessary
to synthesize bioactive 1,25-dihydroxyvitamin D are expressed in the brain, and
hypovitaminosis D is associated with abnormal development and function of the
brain."
17935548 : "CONCLUSION: Vitamin D therapy with conventional treatment improves serum levels
of 25 hydroxy vitamin D but still leaves some patients with significant insufficiency and therefore the same dose of vitamin D is not appropriate for all."
3838342 : "The present studies measure the transport of retinol, retinoic acid,
1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], and 25-hydroxyvitamin D3 [25-(OH)D3]
through the rat brain capillary endothelial wall, i.e., the blood-brain barrier
(BBB). The vitamin A and D derivatives bind both to albumin and to specific
high-affinity binding proteins in plasma. In the presence of physiologic
concentrations of plasma proteins, the extraction by brain of all four compounds
was 5% or less."
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The last indicates that although the quantities are small, oral vitamin D can make its way to the brain. That is not likely to be an accident. If not, then what is being "starved" by these low levels?