High-Dose Vitamin D: Safety Concerns

[PhilC]

Recently, I was doing some research on vitamin D toxicity and found a study that deserves to receive a lot more attention. Looking at a specific autoimmune disease (MS), these scientists found that while moderate doses of vitamin D were beneficial, high-dose vitamin D resulted in disease progression:

“Recently, we could show that in a murine model of MS, administration of a moderate vitamin D dose was of clinical benefit, while excessive vitamin D supplementation had a negative effect on disease severity. Of note, disease exacerbation was associated with high-dose vitamin D caused secondary hypercalcemia. Mechanistically dissecting this outcome, we found that hypercalcemia independent of vitamin D similarly triggered activation of disease-perpetuating T cells. These findings caution that vitamin D should be supplemented in a controlled and moderate manner in patients with MS and concomitantly highlight calcium as a novel potential MS risk factor by itself.”

High-Dose Vitamin D-Mediated Hypercalcemia as a Potential Risk Factor in Central Nervous System Demyelinating Disease
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7053380/

They also pointed out that other researchers had previously shown that a 25-hydroxyvitamin D3 level greater than 125 nmol/L (50 ng/mL) is associated with an increased risk of morbidity and mortality (illness and death). This finding is very significant because it means that the danger zone begins well within the range of vitamin D levels that are currently considered to be “normal” (30−100 ng/mL is a typical reference range).

By the way, the maximum safe dose of vitamin D, called the “tolerable upper intake level”, has been defined by the Institute of Medicine as 4000 IU per day. However, I know from personal experience that it’s possible to experience symptoms of an overdose from taking much less than 4,000 IU of vitamin D per day. The details of that experience can be found in a previous post.

See also:

What Is the Normal Range for Vitamin D in a Blood Test?
https://www.livestrong.com/article/418168-what-is-the-normal-range-for-vitamin-d-in-a-blood-test/

"Unthinking respect for authority is the greatest enemy of truth."
- Albert Einstein

[Linda L]

I know that we are told to take more vitamin D, but my breasts are sore even after taking one capsule. I agree with some that it is a hormone.

RA tried everything: Methotraxate, Arava, Humira. Pneumonia three times. Anemia. Very low iron. Hypothyroidism
AP from April 2014 till August 2015. No luck.
Current medications: Natural thyroid, Mobic, supplements,
vitamins and minerals.
MTHFR heterozygous

[Author]

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