4 ms·

I've always wondered about this deficiency thing. How is it defined, and does it make any sense to claim that such a large part of the population is deficient?

I've always wondered about this deficiency thing. How is it defined, and does it make any sense to claim that such a large part of the population is deficient? Shouldn't that be considered "normal" (excluding the truly pathological cases), as opposed to "above-average"?

Exmoor 6y ago
Average is not necessarily within the healthy range. See also: weight, diet, etc.
valarauko 6y ago
At least for Vit D and B12, the healthy levels were determined by establishing levels in "healthy" cohorts. Deficiency diseases for both of these vitamins are relatively rare, so it is easier to establish a wider "safe" range, rather than "deficiency" ranges. There's been a great deal of debate on safe Vit D levels, and the consensus (such as it is) is that a serum level of 30 ng/mL is likely optimal. Yet there are many studies that show healthy individuals with serum levels < 10 ng/mL, and they do not seem to suffer the bone abnormalities expected. There's a similar situation with Vit B12. Reference ranges were established from healthy individuals based on dietary intake, and there is no upper limit. It's also unclear what the bottom of the healthy range is either. A relatively recent investigation by the health authorities in India found that the dietary intake of B12 of the average Indian was less than a tenth of the US average, with no obvious ill effects. B12 deficiency diseases are practically unheard of in India, yet when tested against American references, a large portion of the population is "deficient". The Indian authorities eventually set the recommended intake of B12 to the WHO standard, which is a lot lower than the American or European levels.
- gridlockd 6y ago
  > Yet there are many studies that show healthy individuals with serum levels < 10 ng/mL, and they do not seem to suffer the bone abnormalities expected. The problem is that any apparently healthy individual may still develop a chronic disease decades down the line. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440113/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440113/ > There's been a great deal of debate on safe Vit D levels, and the consensus (such as it is) is that a serum level of 30 ng/mL is likely optimal. If you look at dark-skinned hunter-gatherer tribes which are living in a way closer to our common ancestors, the "natural" Vitamin-D levels in their relatively sunny environment is more like 40 to 50. The body seems regulate Vitamin-D production up that level, so that's probably closer to optimal than 30.
  - valarauko 6y ago
    >The problem is that any apparently healthy individual may still develop a chronic disease decades down the line. Sure. My impression is that sub 10 ng/mL levels warrant supplementation. However, I have also seen studies that included wrist X-rays of subjects to determine bone loss, and most subjects were sub-20 ng/mL with acceptable bone densities. This was a study in Indians, and another study in rural healthy Indians showed most were in the sub-20 ng/mL range, coupled with low dietary calcium intake, and no ill effect. While it's true that they may develop problems decades down the line, a longitudinal study like this demonstrates that Vit D related deficiency diseases are actually quite rare, and at levels far lower than would be expected from the serum levels alone. There's clearly more going on. https://pubmed.ncbi.nlm.nih.gov/17413106/ https://pubmed.ncbi.nlm.nih.gov/17413106/ On the Hunter-Gatherer levels, I'm guessing you're referring to the Masaai and Hadzabe study. However, is this the optimal vitamin D level? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6180659/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6180659/ This study from healthy black blood donors in Nairobi found much lower levels (95% CI 12.73–22.07), and these people had significant sun exposure as well. Rather importantly, they note that while parathyroid hormone levels are inversely proportional to Vit D serum levels, they start to go up with high levels of Vit D. Individuals with 50 ng/mL vit D had PTH levels similar to people with a Vit D serum level of 15 ng/mL. PTH causes calcium levels in the blood to go up, drawing them out from skeletal reserves. The health implications of high Vitamin D supplementation are linked to the inappropriate deposition of calcium. Keeping PTH levels low is likely beneficial. The Nairobi study found PTH levels were lowest in people with vit D levels around 30 ng/mL.
    - gridlockd 6y ago
      > Rather importantly, they note that while parathyroid hormone levels are inversely proportional to Vit D serum levels, they start to go up with high levels of Vit D. ...in that particular polynomial fit. > Keeping PTH levels low is likely beneficial. The Nairobi study found PTH levels were lowest in people with vit D levels around 30 ng/mL. The minimum of the polynomial fit is around 35. If you look at the scatter plot, there are only six samples near 50 ng/ml and they're all over the place. You can not draw your conclusion from that. There's no significant deviation between 40-50 ng/ml. My question is, why would the body stop producing Vitamin D around 40-50 ng/ml if 30 was optimal? Why not stop earlier? > Keeping PTH levels low is likely beneficial. Not sure where you get that.
- vlovich123 6y ago
  Are there really no better studies than just those that categorize "healthy" cohorts & establish standards from that? That would presume a linear causal relation between "health" and vitamin levels in the body which would flip the order of operations - you want to establish a linear causal relation before you start recommending levels.
  - valarauko 6y ago
    Well, establishing a linear causal relation isn't always possible, at least not ethically. The recommendations have to balance average dietary intake, tolerable upper limits, and what would constitute an adequate intake that is both necessary and sufficient. For Vitamin C, for example, toxicity is probably in the 2-3 grams range, while just 10 mg/day is sufficient to overcome symptoms of deficiency. So what should the recommended daily allowance be? You don’t want to set it at the minimum level, to allow for individual variances and greater needs among particular groups. You also don’t want to set it artificially too high. Different agencies and countries draw that line differently. Japan sets it at 100 mg/day, while India at 40 mg/day. The Indian agencies have to be cognizant of the fact that given average Indian diets, setting the "healthy" level at 100 mg/day would artificially pathologize most Indians who do not suffer from Vit C deficiency symptoms. The situation is more complicated with recommendations around vitamin D. The most obvious and extreme abnormality associated with low D is bone demineralization. This is largely alleviated by levels above 12 ng/mL. Yet when you look a cohort of healthy young Caucasian coast guards, their vitamin D levels are 30 ng/mL. So what do you set as the recommendation: the level required to prevent symptoms, or the levels seen in (some) healthy people, but with no obvious health advantages? Most groups have tended to split the difference: set the minimum at 20 ng/mL, and the “optimal” at 30 ng/mL. Is there a health benefit with supplementing if the level is below 10 ng/mL? Quite likely. Is there a health benefit supplementing if your level is at 20 ng/mL? Probably not. The picture is even further complicated if you consider that the healthy cohort of young white coast guards in Hawaii is not representative of the population at large. Multiple studies have looked at healthy black and brown cohorts from tropical environments, and find most average around 20 ng/mL.
    - vlovich123 6y ago
- eridan2 6y ago
  there are recommended serum levels for B12: >200pg/mL for Europeans
gizmo 6y ago
Excess Vitamin D doesn't do anything (within reason), but the immune system doesn't work properly when you're vitamin D deficient, and this is something we can measure. Humans haven't evolved for an entirely indoor lifestyle, and we need daily direct sunlight in order to function properly.
- exclusiv 6y ago
  I do 5000 IU per day. NIH recommends 600 IU for most people [1]. The Institute of Medicine says 4k IU as the safe upper level of daily intake. Vitamin D does wonders for my skin. Not once did a dermatologist suggest I could be deficient. I figured it out on my own. Here is a good resource for research on vitamins and minerals and their applications: https://www.informationisbeautiful.net/visualizations/snake-oil-scientific-evidence-for-nutritional-supplements-vizsweet/ https://www.informationisbeautiful.net/visualizations/snake-... [1] https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ [2] https://www.healthline.com/nutrition/how-much-vitamin-d-is-too-much#section2 https://www.healthline.com/nutrition/how-much-vitamin-d-is-t...
jibbit 6y ago
Similarly with drinking 3 litres of water a day, or you're dehydrated. How did our ancestors get 3 litres of water a day? Seems like the first person ever who wasn't dehydrated was born around 1985.
- asveikau 6y ago
  I don't know how true it is and I don't remember the source, but I recall hearing somewhere that you also get a lot of hydration through food sources. So it's not necessarily that you need to drink a lot of water to stay hydrated. I guess that might also be why people say to drink more water when you have diarrhea. The absorption of water that usually happens during digestion is not occurring.
- LorenPechtel 6y ago
  The research was seriously misreported--you don't actually need to drink anything like that much, the number is for total dietary intake in any form. With enough juicy food there's no need to actually drink anything. I'm reminded of one day my wife saying she was thirsty, please cut a slice of watermelon. At first I thought it was an English mistake (it's not her native language) but that's really what she meant.

Exmoor 6y ago

Average is not necessarily within the healthy range. See also: weight, diet, etc.

valarauko 6y ago

At least for Vit D and B12, the healthy levels were determined by establishing levels in "healthy" cohorts. Deficiency diseases for both of these vitamins are relatively rare, so it is easier to establish a wider "safe" range, rather than "deficiency" ranges. There's been a great deal of debate on safe Vit D levels, and the consensus (such as it is) is that a serum level of 30 ng/mL is likely optimal. Yet there are many studies that show healthy individuals with serum levels < 10 ng/mL, and they do not seem to suffer the bone abnormalities expected. There's a similar situation with Vit B12. Reference ranges were established from healthy individuals based on dietary intake, and there is no upper limit. It's also unclear what the bottom of the healthy range is either. A relatively recent investigation by the health authorities in India found that the dietary intake of B12 of the average Indian was less than a tenth of the US average, with no obvious ill effects. B12 deficiency diseases are practically unheard of in India, yet when tested against American references, a large portion of the population is "deficient". The Indian authorities eventually set the recommended intake of B12 to the WHO standard, which is a lot lower than the American or European levels.

gridlockd 6y ago
> Yet there are many studies that show healthy individuals with serum levels < 10 ng/mL, and they do not seem to suffer the bone abnormalities expected. The problem is that any apparently healthy individual may still develop a chronic disease decades down the line. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440113/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440113/ > There's been a great deal of debate on safe Vit D levels, and the consensus (such as it is) is that a serum level of 30 ng/mL is likely optimal. If you look at dark-skinned hunter-gatherer tribes which are living in a way closer to our common ancestors, the "natural" Vitamin-D levels in their relatively sunny environment is more like 40 to 50. The body seems regulate Vitamin-D production up that level, so that's probably closer to optimal than 30.
- valarauko 6y ago
  >The problem is that any apparently healthy individual may still develop a chronic disease decades down the line. Sure. My impression is that sub 10 ng/mL levels warrant supplementation. However, I have also seen studies that included wrist X-rays of subjects to determine bone loss, and most subjects were sub-20 ng/mL with acceptable bone densities. This was a study in Indians, and another study in rural healthy Indians showed most were in the sub-20 ng/mL range, coupled with low dietary calcium intake, and no ill effect. While it's true that they may develop problems decades down the line, a longitudinal study like this demonstrates that Vit D related deficiency diseases are actually quite rare, and at levels far lower than would be expected from the serum levels alone. There's clearly more going on. https://pubmed.ncbi.nlm.nih.gov/17413106/ https://pubmed.ncbi.nlm.nih.gov/17413106/ On the Hunter-Gatherer levels, I'm guessing you're referring to the Masaai and Hadzabe study. However, is this the optimal vitamin D level? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6180659/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6180659/ This study from healthy black blood donors in Nairobi found much lower levels (95% CI 12.73–22.07), and these people had significant sun exposure as well. Rather importantly, they note that while parathyroid hormone levels are inversely proportional to Vit D serum levels, they start to go up with high levels of Vit D. Individuals with 50 ng/mL vit D had PTH levels similar to people with a Vit D serum level of 15 ng/mL. PTH causes calcium levels in the blood to go up, drawing them out from skeletal reserves. The health implications of high Vitamin D supplementation are linked to the inappropriate deposition of calcium. Keeping PTH levels low is likely beneficial. The Nairobi study found PTH levels were lowest in people with vit D levels around 30 ng/mL.
  - gridlockd 6y ago
    > Rather importantly, they note that while parathyroid hormone levels are inversely proportional to Vit D serum levels, they start to go up with high levels of Vit D. ...in that particular polynomial fit. > Keeping PTH levels low is likely beneficial. The Nairobi study found PTH levels were lowest in people with vit D levels around 30 ng/mL. The minimum of the polynomial fit is around 35. If you look at the scatter plot, there are only six samples near 50 ng/ml and they're all over the place. You can not draw your conclusion from that. There's no significant deviation between 40-50 ng/ml. My question is, why would the body stop producing Vitamin D around 40-50 ng/ml if 30 was optimal? Why not stop earlier? > Keeping PTH levels low is likely beneficial. Not sure where you get that.
vlovich123 6y ago
Are there really no better studies than just those that categorize "healthy" cohorts & establish standards from that? That would presume a linear causal relation between "health" and vitamin levels in the body which would flip the order of operations - you want to establish a linear causal relation before you start recommending levels.
- valarauko 6y ago
  Well, establishing a linear causal relation isn't always possible, at least not ethically. The recommendations have to balance average dietary intake, tolerable upper limits, and what would constitute an adequate intake that is both necessary and sufficient. For Vitamin C, for example, toxicity is probably in the 2-3 grams range, while just 10 mg/day is sufficient to overcome symptoms of deficiency. So what should the recommended daily allowance be? You don’t want to set it at the minimum level, to allow for individual variances and greater needs among particular groups. You also don’t want to set it artificially too high. Different agencies and countries draw that line differently. Japan sets it at 100 mg/day, while India at 40 mg/day. The Indian agencies have to be cognizant of the fact that given average Indian diets, setting the "healthy" level at 100 mg/day would artificially pathologize most Indians who do not suffer from Vit C deficiency symptoms. The situation is more complicated with recommendations around vitamin D. The most obvious and extreme abnormality associated with low D is bone demineralization. This is largely alleviated by levels above 12 ng/mL. Yet when you look a cohort of healthy young Caucasian coast guards, their vitamin D levels are 30 ng/mL. So what do you set as the recommendation: the level required to prevent symptoms, or the levels seen in (some) healthy people, but with no obvious health advantages? Most groups have tended to split the difference: set the minimum at 20 ng/mL, and the “optimal” at 30 ng/mL. Is there a health benefit with supplementing if the level is below 10 ng/mL? Quite likely. Is there a health benefit supplementing if your level is at 20 ng/mL? Probably not. The picture is even further complicated if you consider that the healthy cohort of young white coast guards in Hawaii is not representative of the population at large. Multiple studies have looked at healthy black and brown cohorts from tropical environments, and find most average around 20 ng/mL.
  - vlovich123 6y ago
eridan2 6y ago
there are recommended serum levels for B12: >200pg/mL for Europeans

gizmo 6y ago

Excess Vitamin D doesn't do anything (within reason), but the immune system doesn't work properly when you're vitamin D deficient, and this is something we can measure. Humans haven't evolved for an entirely indoor lifestyle, and we need daily direct sunlight in order to function properly.

exclusiv 6y ago
I do 5000 IU per day. NIH recommends 600 IU for most people [1]. The Institute of Medicine says 4k IU as the safe upper level of daily intake. Vitamin D does wonders for my skin. Not once did a dermatologist suggest I could be deficient. I figured it out on my own. Here is a good resource for research on vitamins and minerals and their applications: https://www.informationisbeautiful.net/visualizations/snake-oil-scientific-evidence-for-nutritional-supplements-vizsweet/ https://www.informationisbeautiful.net/visualizations/snake-... [1] https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ [2] https://www.healthline.com/nutrition/how-much-vitamin-d-is-too-much#section2 https://www.healthline.com/nutrition/how-much-vitamin-d-is-t...

jibbit 6y ago

Similarly with drinking 3 litres of water a day, or you're dehydrated. How did our ancestors get 3 litres of water a day? Seems like the first person ever who wasn't dehydrated was born around 1985.

asveikau 6y ago
I don't know how true it is and I don't remember the source, but I recall hearing somewhere that you also get a lot of hydration through food sources. So it's not necessarily that you need to drink a lot of water to stay hydrated. I guess that might also be why people say to drink more water when you have diarrhea. The absorption of water that usually happens during digestion is not occurring.
LorenPechtel 6y ago
The research was seriously misreported--you don't actually need to drink anything like that much, the number is for total dietary intake in any form. With enough juicy food there's no need to actually drink anything. I'm reminded of one day my wife saying she was thirsty, please cut a slice of watermelon. At first I thought it was an English mistake (it's not her native language) but that's really what she meant.