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Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

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Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#11

Post by spikels »

ebg13 wrote: post #4

So high doses reduce mineral density but have no effect on strength? How is that possible? Is strength not a function of density?

Here are two possibilities:

1) It probably easier to measure density than strength. Additional measurement noise could mean the strength difference is not statistically significant while the density difference is.

2) The relationship between density and strength is probably not a simple 1:1 linear function. For example a 10% bone mass reduction may only result in a 1% strength reduction. Therefore one many be statistically significant while the other is.

Likely is is a combination of factors like this. Things are rarely simple in the lab.

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#12

Post by maerF0x0 »

> hree-year, double-blind, randomized clinical trial conducted in a single center in Calgary, Canada, from August 2013 to December 2017 ...

Generally speaking, interesting to consider that Calgary is a fairly northern city and they say more northern people get less natural VitaminD from sun exposure... So even in a generally vitaminD short populace the results are showing no stronger of bones. I say all this iirc, not from specific scientific sources...

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#14

Post by maerF0x0 »

DiffEq wrote: post #10
chrisco255 wrote: post #2

I thought calcium had a bigger impact on bone density than Vitamin D?

Generally the greatest way to increase bone density is to lift "heavy" weights. Compared to that any other solution pales in comparison but doctors never seem to prescribe that.

Many things in the weight lifting world revolve around 3 things:

1. Stimulus: ie lifting heavy, nutrients to support hormonal response

2. Materials: ie Calcium / minerals

3. Rest: ie Sleep, recovery time etc.

I would expect any isolated intervention to find lackluster results despite considerable results in conjunction.

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#15

Post by [deleted] »

ChrisSD wrote: post #9

In other words, a lack of Vitamin D reduces bone strength but getting more than necessary doesn't increase bone strength any further. Makes sense. This is often how the body works. You should get enough of but having more than needed doesn't turn you into a superhero (but it can be poisonous).

[deleted]

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#18

Post by dogmatism »

D3 is converted to 1,25(OH)2-D3 which is the active form. The transformation is limited by 1α(OH)-ase which in turn is regulated by levels of calcium and PTH and degraded by renal 24-OH-ase, which previous work has shown is upregulated by high 1,25(OH)2-D3, and 25(OH)D (formed in the liver from the oral cholecalciferol), thereby providing a brake on the system. It has also been shown that the upregulation of 24(OH)ase can be enough to actually decrease 1,25(OH)2-D3 levels, thereby resulting in osteoclastic activity. PTH is also suppressed by high 1.25(OH)2-D3.

tl;dr there are homeostatic mechanisms in place in calcium metabolism that result in a "counterintuitive" reduction in the active metabolite with supraphysiologic supplementation. Also, this is actually in line with prior work, though the authors don't mention any of it until the discussion at the end, and then only two papers. In about 5 minutes of searching, I found papers going back to 1995 suggesting the same thing.

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#19

Post by chrisco255 »

PhasmaFelis wrote: post #16

The results confuse me. Taking 4000 or 10,000 IU results in lower bone mineral density than 400. Is lower BMD better? Otherwise it sounds like vitamin D is actually bad for you.

The study is saying that too much MIGHT be bad for you. 400IUs was the control (not 0). Some vitamins have adverse effects in high doses. Vitamin D might be one of them, but the study just posed the question, it didn't conclude that that was the case. It would take more studies to confirm that.

Re: Effect of High-Dose Vitamin D on Volumetric Bone Density and Bone Strength

#20

Post by AlexanderNull »

Why are there so many studies looking at vitamin D and bone health? Vitamin D levels affect expression of over 400 genes in the human body, make a difference in cancer survival and are strongly inversely correlated with all cause mortality (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103214/ https://www.mdedge.com/psychiatry/article/66349/depression/v... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201256/). Does the lay person really only associate vitamin D with bones?
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