#101

Can you please give me a link to this? Personally I think taking bolus doses once a month is a bad idea and possibly counter productive.

There are quite a few studies done with monthly bolus doses mainly because it is easier to maintain compliance, but that is not how Vitamin D works. I think unprocessed Cholecalciferol is unhelpful (mildly toxic). If all it does to other people is disrupt their sleep for a few days (which it does to me) that is likely to be harmful to wider health.

#103

I think this sort of test is pretty meaningless for two reasons:

a) The two things to test are how much supplementation affects 25OHD levels and what the effect of 25OHD levels is on outcomes. Without the step in between given the other potential sources of vitamin D you cannot really get adequate information.

b) Bolus doses once a month are pretty useless.

They did not measure 25OHD levels so we donā€™t know if they went up high enough to cause an issue. The result is not statistically significant.

I wonder why people put all the effort into massive trials like this which are so badly designed.

However, I would not myself recommend taking 60,000 iu of vitamin D. I experimented personally with taking 24,000 and on another occasion 12,000 and that was bad enough. I find 3,000 of Cholecalciferol to be a nice single capsule. A bit more would probably be OK, but I find 6,000 unhelpful (which is why I use 25OHD to keep up my serum levels).

Looking at my records I might experiment with a higher dose of D3 for a day to see if anything has changed. The last time I tried it was in May 2021. However, that is not a priority.

Thinking about mechanisms this sort of Vitamin D handling could have created a few days of hypervitaminosis (we donā€™t know) every month. That can disrupt calcium processing and cause ectopic calcification.

#104

The largest problem with the study I linked IMO is the post-hoc analysis, Iā€™ve heard thatā€™s not good:

But yes it would be important for the 25OHD levels to be measured.
I am looking into mendelian randomization on 25OHD levels, that should give information.

#105

I donā€™t think post-hoc is as bad as the design.

We know enough about the way vitamin D is metabolised to know that the design has some understandable risks of vascular calcification even if much of it can be reversed. It is not a good idea to test people out by doing this.

#106

Just so Iā€™m on the same page: if I take 5,000 IU of vitamin D daily, that is essentially 150,000 per month?

I have been taking this daily for a year. Last vitamin d blood tests in Jan 2023 were 32(?) ā€” just in the normal/healthy range. Never had a 25OHD test.

Iā€™ve been considering dropping vitamin D to 2,500 per day. But Iā€™m having all kinds of terrific hormonal activity (from heavy weightlifting) and am not sure if the vitamin D is helping this or just incidental.

I had originally decided to take 5,000 daily because of Dr. Coimbraā€™s trials with treating vitiligo using 35,000 daily for six months. But given I have one kidney, I couldnā€™t justify taking 35,000 daily. So I mashed to 5,000 to see if there was an impact (none in a year).

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#107

None of the health agencies recommend take 5000 iu a day, in fact 4000 iu is the upper limit.
I am probably going to stick to 1000 iu a day until Brad Stanfield or similar says otherwise.

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#108

Thank you. But if I were taking 5,000 per day, is that 150,000 per month for the sake of this discussion and the papers Iā€™ve read?

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#109

Yes but @John_Hemming believes that thereā€™s a different effect from having 1 large dose a month rather than everyday. I have not seen convincing evidence from John that itā€™s the case though.

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#110

FWIW

Dr. CĆ­cero Coimbra, MD, PhD personal web site.

Ask him directly, he will reply

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#111

One problem with vitamin D is that it is a fat soluble vitamin, so if you overdo it you canā€™t fix the problem easily. That is probably the toxicity that John is referring to.

#112

The toxicity arises because it can do harm when serum levels are high.

Vitamin d tests tend to be the first metabolite which is 25ohd.

If people take a large dose once a month their serum levels on both d3 and 25ohd will go up then down on a monthly cycle.

Although it averages out over the month if it is over the threshold at which ectopic calcification occurs then that is likely to happen and when it goes down it may not be fully reversed.

This is an interesting paper which found a higher risk of a post operative complications in cardiac patients with a 25OHD level of over 100 nmol/L. What they donā€™t indicate, however, is how high the high ones were furthermore they say:

In line with earlier results,[16] only a small percentage of patients had 25(OH)D levels beyond 100 nmol/L. Nevertheless, the increased risk of MACCE in this subgroup needs particular consideration. At present, possible mechanisms of adverse cardiovascular 25(OH)D effects at levels >100 nmol/L, if any, are unclear. In our study, summer blood drawing was an independent predictor of high 25(OH)D levels. Summer blood drawing is also related to enhanced calcium absorption efficiency from the gut.[33 Excess calcium intakeā€”and thus a high amount of absorbed calciumā€”have been made responsible for an enhanced risk of incident MI,[34] probably induced by a transient rise in serum calcium and subsequent vascular calcification.[35] Interestingly enough, excess vitamin D has also been made responsible for several documented and unforeseeable deaths.[36] However, hypercalcaemia, which is the hallmark of vitamin D intoxication, does not occur unless 25(OH)D levels exceed 375 nmol/L.[37] Note that fasting serum calcium levels did not differ significantly between 25(OH)D categories. Alternative explanations are also possible: high circulating 25(OH)D levels sometimes reflect low availability of the active vitamin D hormone 1,25-dihydroxyvitamin D (1,25(OH)2D),[38]which has important actions on the cellular and subcellular level.[39]Thus, in some cases high 25(OH)D levels may indicate deficient instead of excess vitamin D action. Higher 25(OH)D levels have also been reported in individuals with the APOE ɛ 4 gene variant.[40] Since this gene variant is associated with an increased cardiovascular disease risk, high 25(OH)D levels may probably only be indicative of an increased risk of MACCE but not causally related to it.

The question for which the answer is not clear is how high a serum level of vitamin D (actually 25OHD) has to be before in itself it is dangerous. Obviouly above 375 nmol/l (150 mg/L) causes hypercalcaemia and is considered to be a key threshold. However, a figure lower than that is likely to be hazardous.

#113

I didnā€™t disagree with what you posted, as honestly I didnā€™t read much of it.

But since you ask, my suggestion was more about your lack of manners in bombarding a discussion where you failed to acknowledge the whole point of the PDF that was being discussed.

As for involving yourself in my dosage, recommendations etc. another word of etiquette advice would be to only give advice if someone asks you for it. If you find me rude for breaking this rule myself, in offering that advice about advice, I apologise. It is the nicest way I could think of answering you honestly.

I hope this answer is sufficient for you John as I would prefer not to continue this conversation.

#114

Thanks Joseph, I presume this information was for me? I am not deficient in vitamin D and donā€™t have any major health issues, so was not interested in reading what you offered as advice for my own situation. Instead I thought what you offered might help me learn more about the reasons why vitamin D is sometimes toxic and sometimes beneficial :slight_smile:

#115

There is no need to respond to this. I simply make the point that if someone says they are doing something which I consider may have hazards I think it right that on what is a public form I warn of the hazards.

This is not an environment which involves private conversations. This is a public forum where we discuss the effects of various molecules. If you refer to a website that I believe is wrong I do not need your permission to indicate my view.

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#116

Here is a case of vitamin D toxicity from the British medical journal. But he was taking crazy amounts for a month. Six months later, they still hadnā€™t gone down.

#117

There is a case of people stealing Vitamin D oil, thinking itā€™s cooking oil, and dying from it. That too much Vitamin D is toxic isnā€™t for discussion.

#118

I have some experience with overdoing it. I also have weekly tests measuring 25 Hydroxy vitamin D. The results were (having stopped all supplementation, but not hiding from the sun although I donā€™t live in a particularly sunny area) 419 nmol/l (about 167 ng/ml) then 337 (about 134 ng/ml) then 209.

So in my case (and others may be quite different) it was used up at a rate of between 80 and 120 nmol/L.

For those that donā€™t know 25OHD gets used up by being mainly converted to 1,25 diHydroxy Vitamin D, but also to 24,25 diHydroxy Vitamin D. 1,25 is the active hormone form that acts as a transcription factor inter alia 24,25 has arguments about it, but is generally thought to be either entirely or partially a waste pathway.

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#119

Thatā€™s quite a good video. However, because the maximum blood test reading was 400 nmol/L it does not indicate how quickly the 25OHD was metabolised.

#120

If I am tested at 31 nm/L, barely in the normal range and that is with supplementing with 5000 IU daily, is there any problem with 10000 IU daily to get a more normal level?

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#121

It depends whether your liver can metabolise more. As i said my experience is unmetabolised cholecalciferol disrupts my sleep.

If i were you i would see if i could get some 25ohd to top that up directly. 31nm/l is indeed really low.

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