[thrusong]

I live in Winnipeg, Manitoba where it is quite cold for a big majority of the year. I have dabbled with supplements because I get a couple of major colds every year.

I've heard things like you only need 15 minutes of sunshine per day to get your recommended dose of Vitamin D, but I've also heard it can be quite bad for you if you have too much in your system (and it's hard for your body to flush excess amounts).

If there a safe level of Vitamin D supplements where you won't run this risk? I don't drink milk either because I'm lactose intolerant.

[jerf]

"Winnipeg, Manitoba" ... "only need 15 minutes of sunshine per day to get your recommended dose of Vitamin D"

That doesn't apply to you most of the time, unfortunately. Vitamin D is the result of UVB exposure. For significant portions of the year, you don't get very much [1], compare with, say, [2] Orlando Florida in the US. 10-15 minutes is for a UV index of 7 [3], so that's only 4-6 months out of the year for you. And just based on my couple minutes with Google here, that number may also include the assumption that you're not just "out in the sun" for 15 minutes, but basically sunbathing. Lesser exposure may take longer: [4] Winter times can be effectively impossible because you can't sunbathe at 10 below (regardless of which scale I'm talking about) and you're not going to spend the requisite hours in the sun for what little skin is exposed. Or they can be outright impossible if your skin is dark enough.

[1]: https://winnipeg.weatherstats.ca/charts/forecast_uv-monthly....

[2]: https://nomadseason.com/uv-index/united-states/florida/orlan...

[3]: https://overcomingms.org/program/sunlight-vitamin-d/uv-index...

[4]: https://vitamindwiki.com/dl2105?display

[soperj]

I grew up on the Canadian praries. -10C is basically shorts weather.

edit: seriously though, anything warmer than -10C you'll definitely see kids in shorts. I go skiing in shorts every year.

[IAmBroom]

Wear a g-string if you want. It doesn't make the sunlight any brighter in winter.

[pavel_lishin]

But it does expose more skin, which [3] recommends!

Sadly, it doesn't say how long you should exposure yourself with a UV index of 1, which is what Winnipeg has today, and it's not even proper winter yet.

[jerf]

Yes, yes, you're an invincible winter god upon whom the temperature means nothing. Let us all acknowledge that and bow before you.

Now tell me everyone is doing that, all the time. I also live fairly north, which is part of why I've learned this about Vitamin D in my own research, and I can't help but notice that stores selling winter coats and gloves and other assorted cold gear don't go out of business ever year because nobody is buying them. Nor do I walk through a crowd of people in the middle of winter and have people point and laugh at me because I'm the only one in a coat.

Come on. You're just arguing to argue and swagger a bit, not because you actually think people are getting enough sun exposure in the middle of winter to get enough Vitamin D and there's nothing to worry about.

[soperj]

Just because you're a jerf, doesn't make me one too. Stores aren't going out of business because it gets below -10 regularly.

[zdragnar]

I'm not sure that people downvoting you have been around northerners much. Down here in the upper midwest US, we tend to consider 4 or 5C to be shorts weather in the spring. I've a friend who would wear flip flops / sandals outside down to roughly -10C.

Then again, most people aren't getting the equivalent of 15 minutes of index 7 UVB exposure at those temperatures, so it's not quite the same thing, but still.

[_vqpz]

People are downvoting because it has nothing to do with the comment they're replying to or the original post. Most people are well aware temperature is relative too, I live in the American South and there are certainly people here who will wear shorts in cold or freezing weather too.

[soperj]

> Winter times can be effectively impossible because you can't sunbathe at 10 below

[mwigdahl]

I take 5000 IU per day year round and have not had any issues. Research suggests you can dose 10x that without major problems, although personally I wouldn't go higher than I am already.

https://pubmed.ncbi.nlm.nih.gov/30611908/

[ErikCorry]

That sounds like a lot:

To help prevent vitamin D toxicity, don't take more than 4,000 international units (IU) a day of vitamin D unless your healthcare professional tells you to. Most adults need only 600 IU of vitamin D a day https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...

[scythe]

Part of the issue with vitamin supplements is that the bioavailability can be unpredictable. The actual amount absorbed can vary between 10% and 100% depending on the time of day, supplement formulation, what foods if any are taken together, as well as the particular characteristics of the individual's intestines, which are difficult to assess. Because supplements are not regulated as pharmaceuticals in the United States, this variability can be severe; in the worst cases, supplements do not even contain the active principle.

So, I am not surprised that someone needs to take 5000 IU to get 600 IU worth of effect. Institutional medical authorities are (rationally) quite defensive when cautioning readers about supplement consumption; they must consider the worst case (100% bioavailability) when assessing the risk of overdose.

As an alternative to vitamin supplements, exposing common dietary mushrooms to ultraviolet light converts (by an uncatalysed photochemical reaction) the ergosterol therein to calciferol. How best to achieve this in a home setting is unclear.

[morley]

One number is not going to work for everyone. The only way to be sure is to get a blood test for Vitamin D levels. I get tested with my yearly physical, but if someone really cares they can get more frequent blood tests.

[LocalPCGuy]

As has been commented elsewhere, everyone absorbs vitamin D differently, this really is a matter where someone should just get tested, if they (and their doctor) decide supplementation is needed, do so, test again, and adjust dosage accordingly until desired levels are attained.

Not medical advice here, but harmful effects from vitamin D exposure/toxicity generally only happen at very high levels, or if high doses are taken over long periods of time (as excess can be stored in fatty tissue/liver). Doctors often prescribe a very high dose (like 50,000 IUs) for individuals who are very deficient (often taken once a week, not daily) for a short period before going on a more standard (400-2,000, maybe 5,000) IU dose for maintenance.

[mwigdahl]

The advice on this is all over the map and that's a big problem in the space. Reputable medical sources have recommendations almost two orders of magnitude off from each other at times.

This article, for example:

https://www.ccjm.org/content/89/3/154

...cites several cases where daily supplementation of 50K IU was required to restore normal D levels, although also a case where that same dose caused toxicity. As one of the other commenters in the thread noted, working with your doctor to establish the right level is probably the right move. If nothing else, they have the capability to test your serum levels to see where you're at.

[cgh]

I experimented with taking 10,000 IU a day for about a year. I had my D levels checked with my normal yearly blood test (lipids, etc) and it put me into the high normal range. I still take 5000 IU daily and have for years with no ill effects.

I should note that I live in a place that sees little sun for five or so months a year.

[shmel]

You can't possibly have the same recommendation for all geographies. Florida and Scotland have somewhat different level of UVB especially throughout the winter, come on.

[toomuchtodo]

Vitamin D toxicity is a legitimate concern, so those dosing should be mindful of it, depending on dosage and existing serum levels. Don't action on medical advice from strangers on the internet alone, talk to you doctor or other credentialed medical practitioner you work with if needed.

https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

[lisbbb]

It's bad for your kidneys

[efsavage]

You probably have to really try to take too much Vitamin D with any over the counter supplement (<=5,000 IU), especially if you live that far north. For reference, a prescription dose for someone who is low is usually 50,000 daily.

It should be part of your standard blood tests so you should know if you're running high or low and your doctor can recommend or prescribe a good dose.

[gilfoy]

I’ve had a prescription twice and it was 50,000IU of D2 once weekly. Usually the OTC one people buy is D3.

[more_corn]

If you dry your mushroom the sun they generate a crap-ton of d2. There was a study earlier this year.

[colechristensen]

With 5,000 IU sometimes taking several at a time I had blood levels of Vitamin D at the top of the range which wasn't dangerous it was just informative, "hey you're having enough, tone it down".

[BeetleB]

It's 50,000 weekly.

[milesvp]

First know that the body will stop making vitamin D before you reach overdose quantities. This means you should take vitamin D in the morning.m rather than the evening. Second know that vitamin D is fat soluble. So if you are losing weight, you can more easily overdose if you have high levels stored in your fat. Also know the body won’t absorb as much vitamin D if you don’t take it with fat.

This can make dosing tricky. You can be taking an amount that is safe right now, but then is too much later.

You can max out your body’s vitamin D production even on a cloudy day, though the sun’s angle of incidence effects production.

The body typically maxes production at something like 20k iu (pleae verify this number it has been a while since I learned it), so staying below this number should mostly safe.

The USDA has set its recommended daily allowance mostly to avoid rickets. It is largely considered too low a number for general well being.

I live in north western Washington, and previously used to combat seasonal affective disorder, with some pretty dark thoughts come february. Since I started taking 1k D3 some 20 years ago much of the seasonal mental health has gone away. I take 2k D3 consistently currently, and if I run out for more than a week my mood starts to deteriorate quickly. I still haven’t proved causation since there are likely reasons I’ve let myself run out of the supplement that long, but it is so consistent that I treat it as causal at this point. YMMV

Please do research above just asking a forum for dosing advice though. This is a well educated place, and I would very much trust it as a starting point, but there is a lot of good published content on the topic. Though, I admit google is so bad today, I might fail to find any of the content I referenced years ago… if you use chatgpt make sure to require references, and check them. I find that using multiple instances to review research references separately prevents some context based poisoning as well. And pointing out inconsistencies can be a good way to find nuance in a topic. Though sometimes LLM will just waffle, and the context may be done

[bluGill]

I've heard the 15 minutes is all you need. I've also heard that in winter the sun is so weak that no amount of sunshine gives you any. (even if you were naked outside in winter - risking frostbite).

I'm not a medical doctor. I cannot evaluate any of the above claims. I wish I could find a source I could trust.

[thewebguyd]

Depends on where you are. Latitudes above roughly 35 degrees N, the sun is too low in the sky roughly between October and March to allow for UV-B rays to penetrate, which is what your skin needs to synthesize vitamin D.

So yes, if you live in the northern regions, you don't produce any at all from sun exposure, even on a bright sunny day, during most of the year.

Up here in the PNW, even in the summer, you only have a window of roughly 4 to 5 hours where the sun is high enough, in July.

[snozolli]

I've heard things like you only need 15 minutes of sunshine per day to get your recommended dose of Vitamin D

The figure I read years ago was that it takes 15 minutes in short sleeves to get the necessary light exposure at the 45th parallel in winter. I'm right at the 45th parallel and I don't go out in short sleeves in the winter, so I imagine it's significantly worse for you!

[dooglius]

You can get blood tests pretty cheaply. The safe level is the level that, after you take it consistently, has you in the desired range on the test.

[Etheryte]

You don't need to guess, go to your GP and get yourself tested. It's not expensive, depending on where you're from it might even be free, and usually you get the results back already the next day.

[slow_typist]

EU considers 600 I.U. per day as safe. Probably not enough if the level is low. Blood sampling is cheap, why don’t you have it checked.

[humanfromearth9]

25000 IU weekly during winter is OK, for an adult

[a3w]

An adult with 60 kg or 160 kg of mass?

[BurningFrog]

It's possible to overdose on Vitamin D, but you have to eat absurd amounts.

Unless you eat the pills like candy, you're safe.

[LocalPCGuy]

Generally agree, but unlike water-soluable vitamins, vitamin D can store excess in fatty tissue and the liver, and so if a person takes a large dose (generally 10,000 IU daily or more), they could develop toxicity over time due to the build-up. That's why it's important to test and adjust dosages according to the data.

[hollerith]

Untrue. Source: painful personal experience.

[amanaplanacanal]

How much were you taking?

[hollerith]

I don't remember because it was 25 years ago. Not a huge amount.

[pelzatessa]

I take 8000 D3 (+200ug K2 MK7) daily and I'm fine. since covid I go like this for entirety of winter and then back down when summer comes. Perhaps you live in a climate where you get a lot of sun exposure and somehow overdosed on that. A guy from vitadmindwiki.com even says that you'd have to take 14000IU daily for a year until reaching toxicity limit (although this guy tends to sometimes say different things on the same topic, so I'd be cautious on whether this is the exact amount) https://vitamindwiki.com/Overview+Toxicity+of+vitamin+D

Although it'd be great if you explained what exactly happened, perhaps it wasn't a result of taking vitamin D itself but rather some external thing. Judging by "painful experience" I assume kidney stones, which could be caused by too much calcium or genetic preference. not a doctor or an expert on the topic though, just open for a discussion :)

[hollerith]

The symptoms are hard to describe (but did not include kidney stones), but it was obvious that something was drastically wrong and the drastic wrongness went away in response to my completely avoiding all sunlight and dietary sources of vitamin D and my doing a few other things described below.

Most people could probably take as much supplemental vitamin D as I did without incurring this adverse effect, but there is no straightforward way for a person to know whether they are in the minority of people who will incur the effect. (I do remember that having Northern European ancestry makes the effect more likely.)

The drastic wrongness started showing up after only a few months of whatever high dose of D I was taking (and I regret that I cannot provide this information: I did search for it briefly; but it was definitely not an "absurd amount") so if you've been taking the 8000 D3 for years, then the drastic wrongness is unlikely to suddenly show up in your case -- and if it does show up it would probably be because you contracted some sort of chronic infection.

The presence of certain kinds of chronic infections and genetics are the main causative factors according to the information I relied on 25 years ago. Actually, here is the basic information. I followed most aspects of the protocol including my obtaining a prescription for olmesartan, but then I lost interest when the drastic wrongness went away (after not much longer than 4 months IIRC). I was also probably on an antibiotic during this recovery.

https://mpkb.org/home/patients/protocol_overview

P.S., I take as much MK7 as you do (i.e., twice as much as the "suggested usage" on the label) and have for many years, just without supplemental vitamin D.