Being active and getting outside are associated with a multitude of health benefits and is correlated with vitamin D level. The Vitamin D Council pushes vitamin D supplementation based on this research (and funds it?) but there is minimal methodologically rigorous research showing health benefits from exogenous supplementation.
I started taking vitamin D (D3) because one side of my family has a lot of cancer. Within a couple of days, my mood had stabilized and overall improved. Thinking about it when I noticed this, the only thing that had changed for me was taking the vitamin D.
I’ve since observed that when I run out of vitamin D or forget to take it for several days, my mood slowly declines again. Resumption of vitamin D reverses this.
I did not go into this with any knowledge of such an effect. And the vitamin D influence is stronger in this regard than what I’ve experienced from any (legal) drug. That said, it’s hardly overwhelming. Just a bit more resilience and a bit of protection from feeling overwhelmed.
I now take it in combination with K2 as I’ve heard/read K2 helps keep too much of your calcium from being mobilized by the vitamin D.
The D3 isomer is said to be significantly more bio-available than D1 and D2. And, overdosing does have significant negative consequences over time. So, do your research — and I’m not going to suggest any specific dosages.
But after largely negative experiences with what the pharmaceutical industry has to offer, D3 has been an inexpensive and valuable contribution to my well-being.
I've got to wonder about correlation vs causation.
Normally, as well as food sources, your body naturally produces Vitamin D as a reaction to sunlight (being outdoors), and not having sufficient time outdoors, especially in a pleasant/nature environment, may be contributing to depression.
> I've got to wonder about correlation vs causation.
Link between Vitamin D and depression has been known for a long time. It is not a new finding.
> your body naturally produces Vitamin D as a reaction to sunlight (being outdoors), and not having sufficient time outdoors, especially in a pleasant/nature environment, may be contributing to depression.
At higher latitudes, it is extremely difficult to produce Vitamin D from sunlight unless you expose your entire torso(without a shirt). If you have dark skin, you need 2x or 3x more time.
Again, there is extensive literature on this, you just have to read it instead of speculating.
"Although low vitamin D levels have been observationally associated with depression and depressive symptoms, the effect of vitamin D supplementation as an antidepressant remains uncertain."
I'm not saying you should stop taking it. If it works for you - great. But don't get annoyed at people who point out that the link is tenuous at best.
(Incidentally, it did nothing to improve my mood - but I continue to take it for its other health benefits. I was in the severe depletion zone, and brought it up to mid-normal.)
How is it possible that the football player mentioned in the article can suffer from a deficiency level that's severe enough to collapse?
I would expect that regularly being outside (for practice) and a normal balanced diet would be sufficient to at least get by in a country like the UK. Some depressive/lower energy symptoms during winter time, maybe, but nothing so severe as collapsing.
Shouldn't this problem show up in a much larger portion of the population? Or do very physically active individuals require more Vitamin D?
I don't know about the rest of the UK but here in Scotland the NHS recommends that pretty much everyone should think about taking a Vitamin D supplement from October to March and possibly year round for those people in risk groups:
Because they did not, that's ridiculous. Just correlation. Their symptoms sound very similar to vasovagal syncope, which is a fairly regular occurrence in young healthy people that perhaps skip breakfast and then get their blood drawn / experience nausea / many other causes. They generally recover fine with no intervention other than some rest and getting a meal.
The article even says explicitly:
> While her symptoms are not directly linked to vitamin D deficiency
> Shouldn't this problem show up in a much larger portion of the population?
Casual awareness of studies on this suggest that it DOES show up but the symptoms (lowered immune function, seasonal depression, bone issues) are generic and subtle enough to fly under the radar.
It is not helped that, in my experience, many US health plans do not cover the cost of vitamin D testing without a diagnosis of deficiency (which generally requires a test). While that cost is usually low it does mean that it tends not to be offered because practices tend to avoid non-covered procedures for administrative and billing reasons-- you have to actually ask your physician to do the test.
My understanding is that it is somewhat difficult to end up at serum levels of vitamin D that create actual problems, so in general my not-medical-advice suggestion would be to ask your physician about taking a supplement: they're cheap and if everyone took them it is likely population-level health would improve, and it may dramatically improve your QoL particularly in winter months.
The whole article is about the fact that, in the UK, this is an issue that isn't talked about enough. Also, the most likely reason why not all humans are dark-skinned is that it makes you much more susceptible to vitamin D deficiency outside of the topics.
The UK is pretty far north. We tend to forget this here because the weather is mild, but we're further north than anywhere in the lower 48 US states.
It is not yet the beginning of November and sunset in London is at around 4:37pm. An hour and a quarter earlier than New York. It will be like this or darker until February.
Sun intensity by the middle of the day even on a bright day like today is not very high. For example, compared to New York, the sun intensity at noon on the clearest possible day at the beginning of November is about half as strong. Compared to LA, getting closer to a third.
We also eat fewer carrots than we used to! And we're increasingly deficient in selenium for food globalism reasons; selenium and vitamin D are synergistic AFAIR?
A fair number of people will have been rescued from vitamin D deficiency by the incredible summer we have had, but it is absolutely a thing and we do not hear enough about it.
23 years old. "Played football four times a week and felt fit and healthy."
Not necessarily an eating disorder, but there is high likelihood she is on some sort of diet regime. My money would be on low blood sugar lighting the fire on the vitamin D deficiency. I have seen more than a few "fit" marathon types collapse after missing/skipping a meal. They just don't have the reserves.
I thought it was common knowledge that people with darker skin living further from the Equator have a higher chance of getting vitamin D deficiency and should take supplements. Just like people with lighter skin living closer to the Equator have a higher chance of getting skin cancer and should apply additional sun protection. We have all these adaptations for a reason
Something interesting to me here: "Darker skin" as a standalone term implicitly means white skin is the baseline. We pretty much only see "lighter skin" or "paler skin" when it's in a comparison. We do see the absolute of "pale skin".
There was a nice HN discussion about an M.D.'s blog re: Vitamin D that includes some notes about toxicity. The doctor showed-up on HN and interacted in the comments, too. I found what she wrote to be valuable.
came here to say the same thing; a family member was made unwell by taking vitamin D supplements for something else minor. Nothing bad and stopped immediately.
I find the risk-award very clear: if you are not deficient, taking normal* amount of Vitamin D supplement has no adverse effects; but if you are deficient, the risk is quite high.
*: The normal amount is 600 IU. The recommended upper limit is 4000 IU. The gap is wide.
Eat more mushrooms! Mushrooms contain a natural compound called ergosterol that converts into vitamin D2 when exposed to UV light (similar to our skin!) Even brief exposure to direct midday sun or UV lamps works. Mushrooms are the only non-animal dietary source capable of producing vitamin D. We collaborated on a private astronaut mission to study this in microgravity called Mission MushVroom.
I thought recent research concluded that supplementation doesn’t actually work, and that vitamin D may be a read hearing and it’s actually just a byproduct of the true benefit (proper) sun exposure
Forgive me, I have no link, I feel like medical and nutrition advice changes 180 daily.
Vitamin D does about a million beneficial things. It is not just about secondary effects of sun exposure. Most D supplementation is done purely via pills and the benefits come without sunlight at all.
I think you may be referring to how D isn't a primary treatment for SAD. It certainly doesn't hurt to get more D in the winter for a lot of other reasons, but SAD is primarily treated via light boxes or anti-depressants.
That being said, vitamin D levels are slowly becoming the new "have you thought about losing some weight" in medicine. Being low on it isn't great, but its not the cause of the health problems people complain about.
My brother after moving to NYC from LA suffered from depression during winter each year. Turns out his Vitamin D levels were also extremely low. Once he started supplementing he felt a lot better. Something to also consider and check if you yourself are affected by seasonal depression.
I live in Michigan, and I have always struggled through the winters.
I recently learned that in the winter, in the North, the angle of the sun is such that UVB rays cannot penetrate the atmosphere and your body therefore cannot produce Vitamin D. Surprisingly few people who live here are aware of this.
I take Vitamin D supplements every winter now and I think it makes a difference.
It's amazing how many different vitamins and minerals we really need to get for optimal health, compared to what we actually do get and are able to muddle along for some time with.
Vitamin D is something its easier to find and still people end up deficient and don't realize it. I think it's particularly telling how the article notes the deficiency can start in the mother and immediately be passed along to a child. How do children grow with inadequate foods? Are we collectively failing to reach our potential?
I've marvelled about this at times. This huge list of vitamins the body cannot formulate itself, but is fully designed to make good use of... but also doesn't just immediately crash and go offline if they're lacking. And how the body can hold onto these molecules/atoms for re-use over years and years.
As a irregular Vitamin D supplementer myself I wonder if the effect is that significant for so many people anecdotically, why didn’t have have of Europeans and Russians have severe depression historically.
Having darker skin and living in a high latitude, especially one where it's not always sunny and inviting to be outside in short sleeves/shorts can lead to this. I am outside a lot, but far enough north that soon I will not get any Vitamin D from the sun - I take a daily supplement, it's cheap insurance. Costco sells 600 for $12.50.
Over here Vitamin D often comes in spray bottles that you're meant to just spray in your mouth. It's more convenient for me than a pill because you don't need to open a container or a glass of water, takes 5 seconds.
It's arguably better to count how often one is buying the drops and make an estimation of dosage from that. The daily dosage doesn't matter that much, the aggregate dosage is what's going to count, and it doesn't have to be that precise.
edit: the precision comes from getting blood levels measured after supplementation.
Yes, you can track dosage that way, but squirting it into a beverage and then drinking the beverage is a good way to get off-track. What if you are in the habit of not finishing the entire beverage? Or some reaction or poor mixing occurs? It seems if the directions for a liquid medicine say to squirt it into your mouth, then you squirt it directly into your mouth.
But the trouble with supplementing Vitamin D is that you are treating a symptom. A Vitamin D deficiency usually indicates that you need to touch grass, get outdoors, do some exercise. Since the physician and clinic profit by $0 when they recommend those things, they prescribe you a pill instead. Which idea is a better solution?
Knowing modern medicine, it's quite possible for either case to be true. The test could be biased and the guidelines are misleading or useless for different demographics (I think any demographc that isn't upper class white male have at least one story to tell about this). Or that a population of people could quite generally benefit from more vitamin D.
I think it would be somewhat unsurprising if we find that genes that evolved for one climate are not ideal when migrated to another climate. Especially when we live much longer lives and these kinds of issues are much more relevant to our expected quality of life (ie. how would you know you're vitamin D deficient when you're a peasant who is everything deficient?) Which is all me just saying, I wouldn't be surprised if vitamin D deficiency, which is directly related to sunlight exposure, is a prevalant issue now that humans migrate so much more freely than ever before.
Are you in India? I somehow doubt Indians in India are deficient. The rationale is that when you're closer to the equator, you need less sun exposure to produce the appropriate amount of Vitamin D, so people from that region have inefficient production.
It's when those people go to northern latitudes that the inefficiency starts to matter.
Change my mind:
Being active and getting outside are associated with a multitude of health benefits and is correlated with vitamin D level. The Vitamin D Council pushes vitamin D supplementation based on this research (and funds it?) but there is minimal methodologically rigorous research showing health benefits from exogenous supplementation.
I started taking vitamin D (D3) because one side of my family has a lot of cancer. Within a couple of days, my mood had stabilized and overall improved. Thinking about it when I noticed this, the only thing that had changed for me was taking the vitamin D.
I’ve since observed that when I run out of vitamin D or forget to take it for several days, my mood slowly declines again. Resumption of vitamin D reverses this.
I did not go into this with any knowledge of such an effect. And the vitamin D influence is stronger in this regard than what I’ve experienced from any (legal) drug. That said, it’s hardly overwhelming. Just a bit more resilience and a bit of protection from feeling overwhelmed.
I now take it in combination with K2 as I’ve heard/read K2 helps keep too much of your calcium from being mobilized by the vitamin D.
The D3 isomer is said to be significantly more bio-available than D1 and D2. And, overdosing does have significant negative consequences over time. So, do your research — and I’m not going to suggest any specific dosages.
But after largely negative experiences with what the pharmaceutical industry has to offer, D3 has been an inexpensive and valuable contribution to my well-being.
There have been several studies linking low Vitamin D levels to depression. A meta analysis found improvement when supplements were taken.
https://pubmed.ncbi.nlm.nih.gov/35979473/
I've got to wonder about correlation vs causation.
Normally, as well as food sources, your body naturally produces Vitamin D as a reaction to sunlight (being outdoors), and not having sufficient time outdoors, especially in a pleasant/nature environment, may be contributing to depression.
> I've got to wonder about correlation vs causation.
Link between Vitamin D and depression has been known for a long time. It is not a new finding.
> your body naturally produces Vitamin D as a reaction to sunlight (being outdoors), and not having sufficient time outdoors, especially in a pleasant/nature environment, may be contributing to depression.
At higher latitudes, it is extremely difficult to produce Vitamin D from sunlight unless you expose your entire torso(without a shirt). If you have dark skin, you need 2x or 3x more time.
Again, there is extensive literature on this, you just have to read it instead of speculating.
> Link between Vitamin D and depression has been known for a long time. It is not a new finding.
The link has been disputed for as long.
> Again, there is extensive literature on this, you just have to read it instead of speculating.
There you go:
https://pmc.ncbi.nlm.nih.gov/articles/PMC4008710/
"Although low vitamin D levels have been observationally associated with depression and depressive symptoms, the effect of vitamin D supplementation as an antidepressant remains uncertain."
I'm not saying you should stop taking it. If it works for you - great. But don't get annoyed at people who point out that the link is tenuous at best.
(Incidentally, it did nothing to improve my mood - but I continue to take it for its other health benefits. I was in the severe depletion zone, and brought it up to mid-normal.)
linking.
One could say depressed people stay in bed all day and don't go outside and get sunlight, thus low vit d
if a person wants serious D supplement they need to be doing blood testing, there's no good universal dosage past the level of a daily multivitamin
How is it possible that the football player mentioned in the article can suffer from a deficiency level that's severe enough to collapse?
I would expect that regularly being outside (for practice) and a normal balanced diet would be sufficient to at least get by in a country like the UK. Some depressive/lower energy symptoms during winter time, maybe, but nothing so severe as collapsing.
Shouldn't this problem show up in a much larger portion of the population? Or do very physically active individuals require more Vitamin D?
I don't know about the rest of the UK but here in Scotland the NHS recommends that pretty much everyone should think about taking a Vitamin D supplement from October to March and possibly year round for those people in risk groups:
https://www.nhsinform.scot/healthy-living/food-and-nutrition...
Because they did not, that's ridiculous. Just correlation. Their symptoms sound very similar to vasovagal syncope, which is a fairly regular occurrence in young healthy people that perhaps skip breakfast and then get their blood drawn / experience nausea / many other causes. They generally recover fine with no intervention other than some rest and getting a meal.
The article even says explicitly:
> While her symptoms are not directly linked to vitamin D deficiency
> Shouldn't this problem show up in a much larger portion of the population?
Casual awareness of studies on this suggest that it DOES show up but the symptoms (lowered immune function, seasonal depression, bone issues) are generic and subtle enough to fly under the radar.
It is not helped that, in my experience, many US health plans do not cover the cost of vitamin D testing without a diagnosis of deficiency (which generally requires a test). While that cost is usually low it does mean that it tends not to be offered because practices tend to avoid non-covered procedures for administrative and billing reasons-- you have to actually ask your physician to do the test.
My understanding is that it is somewhat difficult to end up at serum levels of vitamin D that create actual problems, so in general my not-medical-advice suggestion would be to ask your physician about taking a supplement: they're cheap and if everyone took them it is likely population-level health would improve, and it may dramatically improve your QoL particularly in winter months.
The whole article is about the fact that, in the UK, this is an issue that isn't talked about enough. Also, the most likely reason why not all humans are dark-skinned is that it makes you much more susceptible to vitamin D deficiency outside of the topics.
It’s especially an issue for migrants who are dark skinned and move to climates with little light. So yes, I think you are correct.
The UK is pretty far north. We tend to forget this here because the weather is mild, but we're further north than anywhere in the lower 48 US states.
It is not yet the beginning of November and sunset in London is at around 4:37pm. An hour and a quarter earlier than New York. It will be like this or darker until February.
Sun intensity by the middle of the day even on a bright day like today is not very high. For example, compared to New York, the sun intensity at noon on the clearest possible day at the beginning of November is about half as strong. Compared to LA, getting closer to a third.
We also eat fewer carrots than we used to! And we're increasingly deficient in selenium for food globalism reasons; selenium and vitamin D are synergistic AFAIR?
A fair number of people will have been rescued from vitamin D deficiency by the incredible summer we have had, but it is absolutely a thing and we do not hear enough about it.
People with darker skin are at much higher risk.
> Or do very physically active individuals require more Vitamin D?
IIUC, yes they do. They don’t “spend it” as such, they require higher serum levels overall (compared to sedative individuals, all else equals).
Being outside alone isn't enough Vitamin D. In the UK there isn't much sun either.
That doesn't explain why you don't see people collapsing in the UK all over the place.
I would think that there must be something about these individuals, aside from being dark skinned, that makes them more prone to issues.
It's literally just that.
It could be the combination of her being dark-skinned and not receiving it through her diet.
From https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-...
They list oily fish, red meat, egg yolks, fortified foods, and liver. I can see some diets not having those.
23 years old. "Played football four times a week and felt fit and healthy."
Not necessarily an eating disorder, but there is high likelihood she is on some sort of diet regime. My money would be on low blood sugar lighting the fire on the vitamin D deficiency. I have seen more than a few "fit" marathon types collapse after missing/skipping a meal. They just don't have the reserves.
> Shouldn't this problem show up in a much larger portion of the population? Or do very physically active individuals require more Vitamin D?
You ever heard of a thing called a "clickbait headline"?
Did nobody read the article?
> While her symptoms are not directly linked to vitamin D deficiency
I thought it was common knowledge that people with darker skin living further from the Equator have a higher chance of getting vitamin D deficiency and should take supplements. Just like people with lighter skin living closer to the Equator have a higher chance of getting skin cancer and should apply additional sun protection. We have all these adaptations for a reason
It's not common knowledge at all. And in some circles if you bring up physiological differences with skin color it leads to claims of racism.
Australia has seemingly taken the lead on advice (re vitamin d or skin cancer risks) that's based on skin color.
https://www.abc.net.au/news/2024-02-13/sun-safety-position-s...
Traditionally, health notes always just assume you're a white male.
It may be common, but some of us are finding out by reading this comment on hacker news.
Indoor lifestyles mean even people living in sunny climates can have vitamin D deficiency, as can light skinned people.
Someone will probably think you're racist, lmao.
I’ve seen vitamin D overdoses too so be careful. Testing is a cheap and sensible first step
https://mitohealth.com/products/vitamin-d-25-hydroxy-calcidi...
Something interesting to me here: "Darker skin" as a standalone term implicitly means white skin is the baseline. We pretty much only see "lighter skin" or "paler skin" when it's in a comparison. We do see the absolute of "pale skin".
There was a nice HN discussion about an M.D.'s blog re: Vitamin D that includes some notes about toxicity. The doctor showed-up on HN and interacted in the comments, too. I found what she wrote to be valuable.
https://news.ycombinator.com/item?id=24138590
How do you like Mito?
Is there an non-lab way to know if you're vitamin D deficient?
Not taking supplements and live above 35 degrees latitude? Yes
Also old or dark skinned? Double yes.
came here to say the same thing; a family member was made unwell by taking vitamin D supplements for something else minor. Nothing bad and stopped immediately.
PSA that deficiency in Vitamin D also leads to cognitive decline including dementia. https://pmc.ncbi.nlm.nih.gov/articles/PMC6132681/
I find the risk-award very clear: if you are not deficient, taking normal* amount of Vitamin D supplement has no adverse effects; but if you are deficient, the risk is quite high.
*: The normal amount is 600 IU. The recommended upper limit is 4000 IU. The gap is wide.
Eat more mushrooms! Mushrooms contain a natural compound called ergosterol that converts into vitamin D2 when exposed to UV light (similar to our skin!) Even brief exposure to direct midday sun or UV lamps works. Mushrooms are the only non-animal dietary source capable of producing vitamin D. We collaborated on a private astronaut mission to study this in microgravity called Mission MushVroom.
Any kind of mushroom?
But my stomach has no UV light!
Just wait for bioluminescent snake oil supplements soon.
I thought recent research concluded that supplementation doesn’t actually work, and that vitamin D may be a read hearing and it’s actually just a byproduct of the true benefit (proper) sun exposure
Forgive me, I have no link, I feel like medical and nutrition advice changes 180 daily.
Does this ring a bell to anyone?
This is my secret fear was scrolling to see any mention of this.
It’s really hard to believe that all the benefit of the sun can be achieved in a single pill.
I had deficiency, I took supplements, it successfully raised my levels. It was late fall, and I didn't have much sun exposure.
Vitamin D does about a million beneficial things. It is not just about secondary effects of sun exposure. Most D supplementation is done purely via pills and the benefits come without sunlight at all.
I think you may be referring to how D isn't a primary treatment for SAD. It certainly doesn't hurt to get more D in the winter for a lot of other reasons, but SAD is primarily treated via light boxes or anti-depressants.
That being said, vitamin D levels are slowly becoming the new "have you thought about losing some weight" in medicine. Being low on it isn't great, but its not the cause of the health problems people complain about.
"red herring"
why do people do this. It's literally so obnoxious
Do what?
My brother after moving to NYC from LA suffered from depression during winter each year. Turns out his Vitamin D levels were also extremely low. Once he started supplementing he felt a lot better. Something to also consider and check if you yourself are affected by seasonal depression.
I live in Michigan, and I have always struggled through the winters.
I recently learned that in the winter, in the North, the angle of the sun is such that UVB rays cannot penetrate the atmosphere and your body therefore cannot produce Vitamin D. Surprisingly few people who live here are aware of this.
I take Vitamin D supplements every winter now and I think it makes a difference.
https://pubmed.ncbi.nlm.nih.gov/2839537/
My mood has got better since moving from Michigan to Denver
I can see several reasons in that one line that have nothing to do with vitamin-D.
It's amazing how many different vitamins and minerals we really need to get for optimal health, compared to what we actually do get and are able to muddle along for some time with.
Vitamin D is something its easier to find and still people end up deficient and don't realize it. I think it's particularly telling how the article notes the deficiency can start in the mother and immediately be passed along to a child. How do children grow with inadequate foods? Are we collectively failing to reach our potential?
I've marvelled about this at times. This huge list of vitamins the body cannot formulate itself, but is fully designed to make good use of... but also doesn't just immediately crash and go offline if they're lacking. And how the body can hold onto these molecules/atoms for re-use over years and years.
Theranos being back in the news has reminded me how high the demand is for blood test data.
As a irregular Vitamin D supplementer myself I wonder if the effect is that significant for so many people anecdotically, why didn’t have have of Europeans and Russians have severe depression historically.
Just a guess but paler skin tones across the board?
The article addresses that (quite the opposite)
> Those with darker skin need exposure to stronger light to produce the same amount of vitamin D as lighter skin.
As devs who mostly work indoors, checking our vitamin D levels is a must, especially in winter.
Having darker skin and living in a high latitude, especially one where it's not always sunny and inviting to be outside in short sleeves/shorts can lead to this. I am outside a lot, but far enough north that soon I will not get any Vitamin D from the sun - I take a daily supplement, it's cheap insurance. Costco sells 600 for $12.50.
Who knows knows, how would they know!
'Tis the season.
My family just switched to sunrise simulation alarm clock lights, and I'll start squirting vitamin D in my coffee milk soon.
In Europe, winter darkness is a bitch. Don't take chances with your health.
> I'll start squirting vitamin D in my coffee milk
Isn't that more complicated and way less precise in dosage than just taking a pill every day (or a higher dose one every week)?
Over here Vitamin D often comes in spray bottles that you're meant to just spray in your mouth. It's more convenient for me than a pill because you don't need to open a container or a glass of water, takes 5 seconds.
it is very hard to take too much vitamin D
It's arguably better to count how often one is buying the drops and make an estimation of dosage from that. The daily dosage doesn't matter that much, the aggregate dosage is what's going to count, and it doesn't have to be that precise.
edit: the precision comes from getting blood levels measured after supplementation.
Yes, you can track dosage that way, but squirting it into a beverage and then drinking the beverage is a good way to get off-track. What if you are in the habit of not finishing the entire beverage? Or some reaction or poor mixing occurs? It seems if the directions for a liquid medicine say to squirt it into your mouth, then you squirt it directly into your mouth.
But the trouble with supplementing Vitamin D is that you are treating a symptom. A Vitamin D deficiency usually indicates that you need to touch grass, get outdoors, do some exercise. Since the physician and clinic profit by $0 when they recommend those things, they prescribe you a pill instead. Which idea is a better solution?
Me and all my indian friends are deficient in vitamin D . I dont know how those number were calibrated. surely not on Indian population.
Knowing modern medicine, it's quite possible for either case to be true. The test could be biased and the guidelines are misleading or useless for different demographics (I think any demographc that isn't upper class white male have at least one story to tell about this). Or that a population of people could quite generally benefit from more vitamin D.
I think it would be somewhat unsurprising if we find that genes that evolved for one climate are not ideal when migrated to another climate. Especially when we live much longer lives and these kinds of issues are much more relevant to our expected quality of life (ie. how would you know you're vitamin D deficient when you're a peasant who is everything deficient?) Which is all me just saying, I wouldn't be surprised if vitamin D deficiency, which is directly related to sunlight exposure, is a prevalant issue now that humans migrate so much more freely than ever before.
Are you in India? I somehow doubt Indians in India are deficient. The rationale is that when you're closer to the equator, you need less sun exposure to produce the appropriate amount of Vitamin D, so people from that region have inefficient production.
It's when those people go to northern latitudes that the inefficiency starts to matter.
> Are you in India? I somehow doubt Indians in India are deficient.
yes in south india