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Why *aren't* I Vitamin D deficient?

Wolfiness

Activity Level 0
Messages
482
Location
UK
I haven't been outside for years, don't supplement Vitamin D and eat about 1000 kcals' worth of middlingly healthy food per day, so I'm getting about half the micronutrients I should be, no oily fish, very little milk… I've had 2 or 3 general blood tests over the years and none of them found me in deficient in Vitamin D. Any ideas?
 
Messages
2,565
Location
US
Do you eat many mushrooms, cheese, yogurt, orange juice, or fortified cereals?

You are probably insufficient, but not low enough to be deficient. The numbers they use are thought to be too low. They should be telling more people they are deficient and insufficient.
 

Jonathan Edwards

"Gibberish"
Messages
5,256
I haven't been outside for years, don't supplement Vitamin D and eat about 1000 kcals' worth of middlingly healthy food per day, so I'm getting about half the micronutrients I should be, no oily fish, very little milk… I've had 2 or 3 general blood tests over the years and none of them found me in deficient in Vitamin D. Any ideas?

If you eat a normal diet and get at least some sunshine there is no particular reason why you should be vitamin D deficient. Exercise is not relevant - although it will be to bone mass. If you are inside but get sunlight you shouldn't have a problem.
 

aaron_c

Senior Member
Messages
691
If you are inside but get sunlight you shouldn't have a problem.

I am curious where you heard that Dr. Edwards (this is genuine, not sarcastic). I am under the impression that vitamin D is produced from UVB light, and that most window glass blocks UVB light.

@wolfita :

You may want to check out Chris Masterjohn. He makes two points that I think you might find interesting, one of which might apply to your question: 1. For a number of good reasons he thinks that the 80 ng/mL ideal is generally too high. 2. The vitamin D that is usually tested for is the inactive form--25-hydroxy-vitamin D aka 25(OH)D--whose levels only sometimes bear a relation to levels of the active form--1,25-dihydroxy-vitamin D aka calcitriol.

There are a few reasons that the same 25(OH)D level can mean different things for different people. First, calcium deficiency will increase the conversion of 25(OH)D to calcitriol, thus reducing 25(OH)D levels while increasing levels of the more active calcitriol. Second, there is evidence that genetic differences affect how we process vitamin D. Inuits and African Americans, for example, were both found to have lower-than-average 25(OH)D levels but higher-than-average calcitriol levels (see the Chris Masterjohn link above). Third, boron is known to work with vitamin d, at least theoretically by preventing the catabolism of both 25(OH)D and calcitriol via inhibition of CYP24A1.

I'm not sure if any of this will explain your higher-than-expected vitamin D level, but at least it might provide a more complete picture. Finances/insurance willing, you might want to try testing calcitriol. Also, I want to second @SickOfSickness in asking if you eat things that are fortified with vitamin D. I would add soy beverages to that list.
 

Jonathan Edwards

"Gibberish"
Messages
5,256
I am curious where you heard that Dr. Edwards (this is genuine, not sarcastic). I am under the impression that vitamin D is produced from UVB light, and that most window glass blocks UVB light.

Sure, glass reduces UV, but the reality is that lots of people eating a normal diet do not get out in the sun much and at least in the UK clinical vitamin D deficiency is largely restricted to dark skinned people with specific diets and elderly immobile individuals. Presumably others who do not get out much either have the windows open enough in the summer or get enough through the glass.

I am puzzled by why wolfita should think there is a problem here. It seems to me likely that there is none. While it is good to be vigilant I worry that people can end up eating large amounts of unnecessary supplements which all cost money. The main benefactors may be the supplement industry. Do we have any reason to think there is actually any need to take anything here?
 

PeterPositive

Senior Member
Messages
1,426
Well,
I haven't been outside for years, don't supplement Vitamin D and eat about 1000 kcals' worth of middlingly healthy food per day, so I'm getting about half the micronutrients I should be, no oily fish, very little milk… I've had 2 or 3 general blood tests over the years and none of them found me in deficient in Vitamin D. Any ideas?
Well, I had the same problem... was not able to go out i for more than 3 years and my D levels were undetectable. Zero vitamin D3 found. I have been able to reverse the situation last year without supplements, but yeah it can be a serious issue.

These days I have a decent D level, not optimal, but better than diddly squat :)
 

Wolfiness

Activity Level 0
Messages
482
Location
UK
Well, I had the same problem... was not able to go out i for more than 3 years and my D levels were undetectable. Zero vitamin D3 found. I have been able to reverse the situation last year without supplements, but yeah it can be a serious issue.

These days I have a decent D level, not optimal, but better than diddly squat :)

Well, no, I'm saying the opposite, I have no Vitamin D problem despite over a decade of this lifestyle.
 
Last edited:

Wolfiness

Activity Level 0
Messages
482
Location
UK
@Jonathan Edwards, I don't think there is a problem here, I am not a vitamin taker and I don't supplement it. My question is not about whether I need to supplement it, it's about why no need has arisen :D

I am young but immobile, housebound for 15 years, I am admittedly very pale, but because of photosensitivity I have my windows 100% covered probably 95% of the time and 90% covered the rest of the time and as I say my daily food intake is half the RDA and lacking in fish and milk, so why am I not deficient the way an elderly person or @PeterPositive would be? Essentially I'm clutching at straws in a 'let's see if we can identify a metabolic anomaly in case it indicates or leads me to some addressable cause of my illness' type fantasy really.
 

Aurator

Senior Member
Messages
625
I am very fair-skinned. Before I fell ill with ME/CFS I worked and exercised outdoors approximately thirty hours a week. I didn't put on sun block. I was, however, still Vitamin D deficient on a blood test.

I am still vitamin D deficient now (or was at my most recent blood test 6 months ago) though this is understandable perhaps as I am outdoors (i.e. under the sky) considerably less - probably only ten hours a week. Though I'm not worried by it I have to wonder why I am Vit. D deficient. My diet is very good and has been for many years.
 

Gondwanaland

Senior Member
Messages
5,092
I have to wonder why I am Vit. D deficient. My diet is very good and has been for many years.
A diet very high in carbohydrates (esp. whole grains) is known to deplete vit D due to its role in insulin sensitivity.

About excess in vit D, I second @aaron_c . 1,25 vitD should be tested too to see if there is a calcium problem going on.

Studies on people who lead an active life under the sun in the tropics found unexpectedly low levels of D (I suppose the high carb diet is to blame).
 

TigerLilea

Senior Member
Messages
1,147
Location
Vancouver, British Columbia
Studies on people who lead an active life under the sun in the tropics found unexpectedly low levels of D (I suppose the high carb diet is to blame).
The darker a person's skin, the less Vitamin D their body makes. Dark skin acts as a sunscreen. Lighter skinned people make Vitamin D much quicker and are less likely to be deficient.
 

Wolfiness

Activity Level 0
Messages
482
Location
UK
Ah interesting @aaron_c . As I say, it doesn't bother me and when I do supplement it I don't feel any better so I presume there isn't a problem. :)
 

Scarecrow

Revolting Peasant
Messages
1,904
Location
Scotland
I haven't been outside for years, don't supplement Vitamin D and eat about 1000 kcals' worth of middlingly healthy food per day, so I'm getting about half the micronutrients I should be, no oily fish, very little milk… I've had 2 or 3 general blood tests over the years and none of them found me in deficient in Vitamin D. Any ideas?
By contrast, I'm not housebound, get a reasonable exposure to sun (given geographical limitations), eat oily fish, drink milk etc and am on the wrong end of insufficient.
:rolleyes:

Maybe we just have different utilisation rates?

p.s. when aaron_c was quoting levels, they were in ng/ml and need to be multiplied by 2.5 to convert to nmol/L
 

aaron_c

Senior Member
Messages
691
@Scarecrow thanks for clarifying the conversion.

Sure, glass reduces UV, but the reality is that lots of people eating a normal diet do not get out in the sun much and at least in the UK clinical vitamin D deficiency is largely restricted to dark skinned people with specific diets and elderly immobile individuals. Presumably others who do not get out much either have the windows open enough in the summer or get enough through the glass.

Thank you for taking the time to share your clinical experience with us. And I want to make it clear that I am not implying that @wolfita 's levels are unhealthy. As I wrote above, I follow Chris Masterjohn in his suspicions both of the current higher recommendation for 25(OH)D and of drawing too many conclusions from 25(OH)D levels.

I am not yet convinced, however, that sunlight through windows could possibly be responsible for the relatively low level of vitamin D deficiency in the UK. Here is a well-researched article that analyses UV exposure through glass. The author states that "glass effectively blocks all of UVB radiation."

It seems much more likely to me that most people who "don't get out much" get their vitamin D from some combination of vitamins, fortified foods (breakfast cereals, orange juice, milk, et) infrequent sun exposure and in some cases open windows in the summer than by getting the virtually non-existent UVB through windows.

@Gondwanaland : I looked at the google results you linked to. I see articles indicating that low vitamin D is associated with insulin resistance, and that supplementing vitamin D reduces insulin resistance, but I am not seeing something that says that insulin resistance lowers vitamin D (admittedly my search was not exhaustive). Do you have a link to an article like that?

@wolfita : You didn't say, so I thought I'd ask again: Do you eat any foods fortified with vitamin D?

For what it's worth, I think you have a good question. And provided you don't eat vitamin-D-fortified foods, don't open your windows, and don't take calcium or boron supplements, I don't have a good answer for you.
 

Gondwanaland

Senior Member
Messages
5,092
@Gondwanaland : I looked at the google results you linked to. I see articles indicating that low vitamin D is associated with insulin resistance, and that supplementing vitamin D reduces insulin resistance, but I am not seeing something that says that insulin resistance lowers vitamin D (admittedly my search was not exhaustive). Do you have a link to an article like that?
My suggestion of key word is "hyperinsulinemia"
 

Wolfiness

Activity Level 0
Messages
482
Location
UK
@wolfita : You didn't say, so I thought I'd ask again: Do you eat any foods fortified with vitamin D?

Tbh I can't remember what my diet was like when I had these tests done :) There was probably 150-200ml of juice a day at times and I might have been putting some milk or soya in my tea and I have at various times eaten muesli at about 50-150g a day but with water not milk/juice/soya - these are phases rather than all the time so I'm not sure. Wouldn't the same be true of the D-deficient elderly though?
 

aaron_c

Senior Member
Messages
691
Wouldn't the same be true of the D-deficient elderly though?

The only thing I can think is that the elderly have impaired lipid digestion/absorption, so perhaps you absorbed more of the vitamin D than they did.

I think it's a good question and once again I am far from sure that what I suggest is the whole story.
 

Gondwanaland

Senior Member
Messages
5,092
There was probably 150-200ml of juice a day at times and I might have been putting some milk or soya in my tea and I have at various times eaten muesli at about 50-150g a day
I wonder if the vit D spikes before going down...