> 40.7% of participants had 25(OH)D levels of less than 20 ng/mL at baseline, and according to current guidelines, all were allowed to take 800 IU/d of supplemental vitamin D outside the study medication.

So, even the controls were given D3 supplements if they were deficient. That kind of throws the whole study into question.

It might also be worth mentioning that measuring 25-hydroxy is also an approximation at best. That still has to be converted to 1,25-dihydroxyvitamin by the kidneys. People with high insulin resistance (diabetics, pre-diabetics) or kidney damage tend to have problems converting 25-hydroxy. Measuring 25-hydroxy is primarily used for toxicity and even that has variables that are difficult to measure, so a statistical baseline is applied.

> That kind of throws the whole study into question.

Well, that turns it into a study that checks if extra vitamin will have an effect, even when there is no deficiency. It doesn't throw the study into question, but it may not apply to what the people on this thread are talking about (what's never clear).

I'm not so sure it does, as something like 800 IU of Vitamin D is the daily minimum.

I have not looked at the underlying study, but that article definitely does a terrible job of being clear on the caveats of the study. E.g. this nugget was left for the last paragraph of the article:

"Our exercise intervention was a simple home strength exercise program, which likely was not challenging enough in our unexpectedly active study population, where over 80% already engaged moderate to high intensity exercise," she said.

I would take anything from this study with a pinch of salt. I doubt if it was a well controlled study.

One important factor in vitamin studies is the prevalence of vitamin deficiency in a particular population. E.g. vitamin D in the US might not be as effective because it is already added into many food products, e.g. milk, which is not the case for other countries.

Even within a population, vitamin D deficiency will vary by lifestyle, skin tone, and climate. All three of which vary a lot in the US.

My understanding is that even the definition of what constitutes deficient isn't settled due to how it's measured. For example, many African Americans show deficient even though it's believed they aren't.

In Germany (probably in most european countries) it's not allowed to add vitamin D to food. So it's really important to know about it.

Still, almost no one knows about it...

Vitamin D is added to milk and butter in Sweden, even obligatory for some kinds! But that's because of our sad lack of sunshine for many months on end of course, so I expect the other nordic countries does something similar.

Or just get some sunshine! It's likely there are other benefits, besides just the vitamin D.

> Or just get some sunshine!

Where I live I haven't been able to get sun actually on my skin for the last three weeks.

I saw sunshine through the window one day last week while in a meeting, but it was gone an hour later. According to my weather app the next break in cloud is more than a week from now.

Even when there is sunshine in the winter, it's often too cold to expose more than a tiny amount of skin anyway. Please don't assume we all live in California.

>Please don't assume we all live in California.

Same here, although at least there's sun on weekends for me (if it isn't cloudy). Looking out the window, and being outside on the weekend with a winter hat and long sleeves is probably not allowing a lot of vitamin D.

I'm wondering if there's something like a good lamp that gives UV light without being too strong.

UV bath in Russia.

https://www.nationalgeographic.com/photography/photo-of-the-...

Sure, but the winter climates in many geographical regions don’t provide adequate sunlight during winter.

I was pretty amazed to Discover that Spirit Airlines is doing round trip flights for $75 to Orlando from my local airport. If you’re in the Midwest in a midsized city that’s cold and dreary in winter there’s a good chance you can find a similar deal.

A lot of this interest in vitamin D is motivated by the desire to not die from getting infected with sars-cov-2. Or not dying in general. Travel like that is counter-productive currently.

I know different people have different risk tolerances, but there’s no way I would get on a plane during a pandemic if I don’t have to.

An airplane is probably a safer place to be than your local grocery store right now.

Unless airplanes are alternatives to grocery stores, even if that comparison was accurate it would be meaningless.

At the grocery store I can bolt at a moment’s notice if I see anything sketchy happening. No can do on an airplane. There could be a guy sitting next to me and coughing all over me for hours.

Am I the only one who finds it laughable to consider trusting the word of companies the likes of Delta, Southwest, and US Air? They seem fundamentally incompetent in pretty much every other aspect of anything that doesn't involve literally keeping the plane from crashing. Why would I believe the air filtration systems are even going to be operational, say nothing about effective when they are?

Pressurized airliners have about 15 air changes per hour or 3-4x what’s typical in an office building. This is air exchanges with the outside, not filtration cycles which are in addition. Even if the filters were entirely INOP, I suspect you’re no worse off than sitting in an office building.

Now, I’m not doing that right now, but there’s little reason to think major US carriers aren’t doing what they say they’re doing and if the air change mechanism wasn’t working, you’d see oxygen masks deploying as that’s the mechanism by which the aircraft remains pressurized.

Sitting in an office building is one of the worst places you can be for avoiding getting sick.

Kids kind of makes it all pointless. They catch everything and bring it home.

It was nice not being sick for so many months.

2 weeks after they went back. Bam, everyone sick.

And that’s with intense mask rules and distancing

You're not wrong, but that doesn't mean that we can't take other measures to get back below R=1. The primary one I can think of is for governments of the world to give long term contracts to N95 mask makers so they can fully spin up their factories. It's been 9 months for $diety's sake.

Non-fit homemade and non-rated masks help prevent others from getting sick. But if everyone had access to cheap N95 that actually prevented them from getting sick we'd be a lot better off. The kids would still be getting it and getting everyone sick at home/school because they wouldn't wear them consistently right, but people without kids at home wouldn't be getting sick at nearly the rate. Every bit counts.

Maybe the masks and distancing don't actually work?

I don't know if this is mind blowing or not because people don't seem to use it but...

If you live in a suburb or further out, basically every major grocery chain does pickup orders.

I order online, drive to the store, and an employee puts the groceries in my trunk. I never go inside.

It's also... free. So anyone with a car(most of us in the USA/CA) can do it.

Congratulations, you have proposed the least ecologically sustainable vitamin boost I've ever heard. Every day brings new surprises.

That doesn't work at the latitudes some of us live at.

https://new-wayland.com/blog/onward-to-100-nmol/

Correct. Perhaps even more important than vitamin D is nitric oxide. The summarised advice is to avoid the sun when it is high in the sky (noon-ish), get some sun in the mornings/evenings, and supplement vitamin D. This ensures good levels of vitamin D and nitric oxide while reducing skin cancer risk.

Details here: https://youtu.be/Kvh4D_osFXs

Oddly the study didn't seem to state (from the abstract anyway) if the participants were deficient in vitamin D to start with or not.

Well I mean, in Australia, that leads to skin cancer, so I'll just take some tablets thanks!

Doctors in Australia recommend approximately 15 mins of sunshine a day in Australia.

This is pretty easy to achieve, even in winter, for us... and is unlikely to "lead to skin cancer"

We're starting to get into some pretty controversial territory here, but I think you're probably better off still getting at least SOME sunshine.

It's speculative, but I believe the skin cancer risk can be dramatically reduced by making sure you're not getting too much linoleic acid in your diet (note: you really have to try at this, tho -- almost every1 is!).

Here's a study in mice:

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-1097....

Of course, that's not humans, but I think the fundamental mechanisms at play should be the same.

More broadly, this article is interesting, and makes the case for more sun exposure:

https://www.outsideonline.com/2380751/sunscreen-sun-exposure...

Interesting. Other information [0] suggest that I should consume more lineolic acids compared to other fats to help my risk of Heart Disease that runs in the family. Not looking good for me hey!

[0] https://www.hsph.harvard.edu/nutritionsource/2014/11/05/diet...

Vitamin D taken via pill is not the same an that manufactured by sunlight. The pill form has side effects like causing too much absorption of calcium in the intestines, which leads to other problems. This is something that doesn't happen from sunlight.

I’m allergic to the sun. Autoimmune. A day in full sun will mean months of agony.

No. I'm a computer scientist and work at the computer. In my free time i play at the computer. I don't like to walk around for kilometers in my free time.

Just because some people want to do it / can do it, it is not the same for everyone.

There's a big difference between the amount you need to not get rickets (around 100 IU) and the amounts that seem to move the needle on other outcomes (2000 IU or more). The study used 800 IU which to me, isn't great.