Vitamin D, red light therapy, insulin attenuating response of a walk, immunological benefit of allergen exposure, cognitive noise reduction and rest response of walks in forests.
Man keeps trying to bring the outdoors inside.
Most vitamins are a waste of time and money, some are even harmful[1], but there are a lot of people with D deficiency, especially in winter[2].
1 https://www.mdpi.com/2072-6643/17/17/2744#:~:text=highest%20...
2 https://www.abs.gov.au/articles/vitamin-d#edit-group-image--...
This paper states:
> The study protocol was approved by the Institutional Ethics Committee and registered with the Clinical Trials Registry of India
As far as I can tell, that registry is here: https://www.ctri.nic.in/Clinicaltrials/pubview.php
Doing a keyword search for the first author's last name reveals zero hits. (It's possible I'm missing—that search does not inspire confidence.)
Glad to see this study, seems decent, but for a different perspective there was a relatively recent meta-analysis on the effectiveness of Vitamin D for RIs that suggested no effect:
https://www.thelancet.com/journals/landia/article/PIIS2213-8...
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.
A few other interesting links with Vitamin D absorption. Surprised nobody has brought up gut dysbiosis and the role microbiome plays in Vitamin absorption. I'm finding it increasingly difficult to discern whether the things we consume are for the direct benefit of our cells and metabolic needs or via a more indirect path if the things we consume directly affect the microbiome within us which then translates into either nourishment or inflammation within us. Since microbiomes can change rapidly in composition, this feels like a game of nurturing over the long-haul with some minor blips along the way.
[1] "connection between vitamin D and the immune system through gut bacteria and may have applications for improving cancer therapies"
[2] "How the Gut Microbiome Affects Vitamin D Absorption"
[3] "vitamin D may affect the host-microbiota relationship."
[1]: https://www.science.org/doi/10.1126/science.adh7954
[2]: https://www.gutnow.com/medical-treatments/how-your-gut-micro...
I take 10k IU of vitamin D if I feel a cold coming on. I used to get extremely bad colds very frequently, and every time I get frustrated and read whatever research might be helpful. A year ago I came across some info about LL-37, and found that vitamin D might help, and that's when I started taking it. https://pmc.ncbi.nlm.nih.gov/articles/PMC9134243/
The big dose of D seems to help. I'm certain I'm deficient, since I already take 2-4k daily, which noticeably helpsy winter blues. It's the first time I can "arrest" a cold, and even if I get sick the symptoms aren't nearly as bad.
My full protocol for if I start feeling a cold is this:
1. 10k vitamin D 2. Stay extremely warm when I sleep. Uncomfortably warm. 3. Butyrate (probably a placebo) 4. Curcumin (almost certainly a placebo).
I personally found that taking vitamin D regularly dramatically reduced how many colds I got (10 in 2024 vs. 1 in 2025).
I take 2,000 IU per day, typically without a meal.
In the US it is very easy to test your vitamin D levels. I recently had mine done and was just below normal range. Started supplementing and will test again in 6 months.
A lot of people are critiquing the statistical methods and quality of the study, which is fine. But it's worth pointing out that you—the individual—should not be concerned with someone else's p-value. You should be concerned with maximizing your own utility. A safe, possibly effective, and cheap intervention is probably worth trying. If it was more expensive or less safe, it would require more evidence to try.
Take it from an academic like me that peer review in just over a month is rare and a sign of low-quality editorial work at the journal (the exceptions would be the most open, progressive journals like PCI and similar).
The formatting/style and peer review history alone are enough for me to doubt this. Of course, the other users' points about study design and lack of transparency make it even harder to trust the claims.
Do we really know what "optimal" vitamin D levels are? I've heard a wide range of answers on this, and it's not even clear to me that we know whether there is natural human variability in the amount needed.
I haven't seen convincing evidence that vitamin D supplementation is materially useful for anything but rickets. I get the impression that naturally high serum levels are an effect rather than a cause of other positive things, and that supplementation mostly increases serum levels without effecting positive things. It doesn't seem harmful either, so can't hurt might help?
Reminder that the Recommended Daily Allowance of Vitamin D found on all the labels (800 IU) is mistakenly too low, by a factor of 10x, due to a maths error (should be 8000 IU). It has not been corrected yet. Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/
Supplementing with vitamin D is honestly one of the easiest things you can do... it's cheap, available everywhere, and makes a real difference. Just make sure you're also taking magnesium citrate (or another good form of magnesium) with it, since your body needs magnesium to properly use vit D
What about the article that that talks about Vitamin D being the same chemical as rat poison and that the positive effects it has on our bodies may be due to the fact that we are low-level poisoning ourselves with it?
"Vitamin D3, also known as cholecalciferol, is used as a rodenticide because it is highly toxic to rodents when ingested in sufficient quantities. It functions by causing a life-threatening elevation in blood calcium and phosphorus levels, leading to severe acute kidney failure"
"Despite its use in rodenticides, vitamin D3 is safe for humans and pets when consumed in normal dietary or supplement doses. However, extremely high doses of vitamin D3 can be toxic to humans as well, potentially leading to hypercalcemia, kidney stones, and renal failure. The difference in susceptibility between rodents and humans is significant; rodents are much more sensitive to the effects of cholecalciferol, which is why it is effective as a rodenticide."
The theory is that we are just poisoning ourselves by taking it and that our bodies react to being poisoned with the positive effects that are well documented and observed.
Can confirm anecdotally. I used to get 2-3 colds a year for about 15 years straight, especially during season changes when the humidity levels changed. Started taking 5000 IU vitamin D3 daily about 2 years ago and I haven't gotten sick since.
I was pretty sure we already knew vitamin D deficits dampen the immune system.
I wonder why we didn’t recommend vitamin D during Covid?
I'm confused - Vit. D is essential for the immune system and most people are deficient - why isn't this obvious.
I wonder if adding zinc on top of this would do.
3-4 years ago this submission would be flagged in seconds just because of the word Vitamin D.
Heliotherapy is well-due for a resurgence. One of my favourite youtubers (conquer aging or die trying) has a great interview with a medical doctor about sunlight as a medical intervention. Well worth the watch:
Newsflash: When you are sick, addressing comorbid conditions helps you get better faster.
Interesting how your government did not mention Vitamin D during the COVID scare.
Breaking news! Water proven to clench thirst among those who are thirsty!
So a vitamin deficit is bad for your health.
Shocker.
Just turn on an uv light for a few hours. Problem solved.
Anecdotal but when I'm sick I double my vit C and D intake which typically helps me.
Unfortunately Vitamin D deficiency tests (probably it is not covered by your insurance), high dose supplements are currently pushed so much by Doctors I started to think this is almost a scam. Most of the research about the subject are very noisy and conflicting.
"Exercise" not found in the shared text.
I'm sure people who supplement or have good D levels also take care of themselves, generally - because they know D is one of the supplements that make a difference both somatic and psychological.
And thus do better with flu/cold.
Heh...this is a shady study if I ever saw one.
-- Exactly 400 study participants recruited.
-- Exactly 193 of 200 participants completing the study in each group (which, for a study administered in a community setting, is an essentially impossibly-high completion rate).
-- No author disclosures -- in fact, no information about the authors whatsoever, other than their names.
-- No information on exposures, lifestyles, or other factors which invariably influence infection rates.
-- Inappropriate statistical methods, which focus very heavily on p values.
-- Only 3 authors, which for a randomized controlled trial involving hundreds of people in different settings with regular follow-up, seems rather unlikely.