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  • Vitamin D dosage and body fat

    I have been taking vitamin D for some years and keep an eye on the various opinions on how much to take. I've seen 10,000 iu per day, 100iu / 25lb body weight and so on.

    But I have always found that I get pretty high Vit D test readings from relatively low dosages - 2000-4000 iu per day, so I've been a little careful on how much I take, and a little scpetical of the higher dosage recommendations.

    Then something yesterday gave me a possible a-ha moment. I was at the gym taking a pal through a workout - he's losing weight by going Primal. The gym instructor got out the body composition machine afterwards so we could monitor his fat loss. He came in at 25%. Then the guy stuck me on it as a comparison and I came in at 3.5% (!)

    The machine tells me that he therefore has 3 st 7 lb of fat, and I have a measly 5.4 lb. That's, what, 7-8 times as much fat?

    I know this is probably too low, and I'm working on it (watch out sweet potatoes, here I come!), but it made me think about vit D dosage.

    Seeing as Vitamin D is a fat-soluble vitamin, then does it follow that those with more body fat need more vitamin D to reach a certain tissue concentration?

    This would explain why I, with my stupidly low body fat, get high vit D test readings on relatively low doses.

    Hmmm... anyone care to stroke their chin over this one?
    My primal journal
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  • #2
    I think it's pretty well known that the fatter you are, the more Vitamin D you require...

    also, the older you are.
    and if you have darker skin.
    and you live in a northern latitude.

    There are even more factors. I don't remember them all.

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    • #3
      I had my first real physical 4 months ago (42) and the doctor put me on a low dosage of blood pressure medicine (which did not surprise me) but also put me on prescription Vitamin D. It was a 10,000 ui pill but I was only supposed to take it twice per week. I just went back and had my blood retested and my Vitamin D levels were back to normal levels. He suggested I now go to an over the counter solution for the Vitamin D and told me to go with the 1,000 ui dosage each day. At least according to him, there is no need for higher dosages.

      Yes, the fatter you are the more Vitamin D you need. Recently heard this on the Dr. Oz show and was also confirmed by my doctor.

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      • #4
        I think you'll find on Cillakats vit d thread she recommends 1000iu per 25lbs of body weight.

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        • #5
          OK, so it seems I'm a bit behind the times here! Nice to have an explanation for why my levels were so high on a relatively moderate dose though, and perhaps a warning for other skinny types to watch their dosage rather than following a 'one size fits all' prescription.
          My primal journal
          You might find these handy: Free gluten free restaurant cards in 50+ languages
          In Praise of the Primal Lifestyle

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          • #6
            Great posting for me, thank you. I am just starting to supp. again now that I'm not getting so much sunlight on my body. At 100 lbs and 'athletic' BF% for a woman I had better not overdo it.

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            • #7
              I think Cillakat is always pretty careful to say that 1000 IU/lb body weight is only a safe place to start until you get tested in 3 months, not as a substitute for getting tested.

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              • #8
                i dunno if this is relavant but the more sun/vita D i get the better i handle carbs
                Get on my Level
                http://malpaz.wordpress.com/

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                • #9
                  Testing is clearly vital, as you say Avocado
                  My primal journal
                  You might find these handy: Free gluten free restaurant cards in 50+ languages
                  In Praise of the Primal Lifestyle

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                  • #10
                    Here is an alternative opinion.

                    A friend is taking 20,000 IU Vit D3 daily. His doctor told him that he could not overdose on Vit D3, so advised taking a large dosage every day to be certain of getting enough. He has been doing this for 2 years now, and has not noticed any ill effects. He laughed at me when I suggested he get his blood tested for Vit-D levels.

                    Could this be TRUE? Off to my favorite authority: Wicki Says:
                    "In healthy adults, sustained intake of 1250 micrograms/day (50,000 IU) can produce overt toxicity after several months"
                    http://en.wikipedia.org/wiki/Vitamin...e_by_ingestion
                    Another series of studies concludes similar results:
                    They go on to state, "...cases of vitamin D toxicity with hypercalcemia, for which the 25(OH)D concentration and vitamin D dose are known, all involve intake of (greater than or equal to) 40,000 IU/d."

                    That's Forty Thousand IU's per day to produce a true Overdose on Vitamin D with the required Elevated Calcium levels to go along with it! That's NOT what doctors and governments are telling us, so doctors give us inadequate amounts of Vitamin D in order to prevent a nearly fictitious possibility of overdose on Vitamin D!

                    Another study gave pregnant women 100,000 IU's per day for the entire length of their pregnancy. The study concluded,"Thus, there is no evidence in humans that even a 100,000 IU/d dose of vitamin D for extended periods during pregnancy results in any harmful effects."
                    http://www.easy-immune-health.com/Ov...Vitamin-D.html
                    Bottom line:
                    So it appears that my friend is no where near overdosing at only 20,000 IU per day, and his doctor is correct.
                    No doubt there are conflicting studies out there. Aren't there always? Nutrition is NOT an exact science!

                    Best of health to all,
                    Grizz
                    Last edited by Grizz; 10-01-2010, 03:23 AM.

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                    • #11
                      Personally, I prefer not to supplement anything if I can help it and instead adjust my diet to meet my requirement.s In the case of vitamin D this is clearly not possible, living where I do, and while I am aware that actually producing vit D toxicity is quite hard, I am not yet convinced that there may not be other issues with constantly high blood levels.
                      My primal journal
                      You might find these handy: Free gluten free restaurant cards in 50+ languages
                      In Praise of the Primal Lifestyle

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                      • #12
                        Originally posted by racingsnake View Post
                        I have been taking vitamin D for some years and keep an eye on the various opinions on how much to take. I've seen 10,000 iu per day, 100iu / 25lb body weight and so on.
                        I tend to recommend 1000 IU/25lbs body weight but clarify that there is significant variation and testing really is required.

                        But I have always found that I get pretty high Vit D test readings from relatively low dosages - 2000-4000 iu per day, so I've been a little careful on how much I take, and a little scpetical of the higher dosage recommendations.
                        I track D levels for 106 people. A few people, like you, maintain 65-80 ng/mL on 2,000 IU per day in the absence of any sun exposure.

                        Then something yesterday gave me a possible a-ha moment. I was at the gym taking a pal through a workout - he's losing weight by going Primal. The gym instructor got out the body composition machine afterwards so we could monitor his fat loss. He came in at 25%. Then the guy stuck me on it as a comparison and I came in at 3.5% (!)

                        The machine tells me that he therefore has 3 st 7 lb of fat, and I have a measly 5.4 lb. That's, what, 7-8 times as much fat?
                        I have entertained the same theory but am not finding that to be the case. I've seen very very low body fat men and women need the 1000 IU per 25ls body weight per day to maintain levels and I've seen the reverse.

                        Keep in mind that there are problems with vitamin d tests if they're not using DiaSorin/LIASON....and in the US that means using labcorp. In other parts of the world, there may be MAJOR problems with D testing validity.

                        This would explain why I, with my stupidly low body fat, get high vit D test readings on relatively low doses.
                        The main issues seem to be:
                        1) genetic differences in Vitamin D binding protein
                        2) inflammation

                        There are some other issues with digestion, fat absorption/assimilation and perhaps variations between vitamin D supplements and 'user error' (inconsistency in dosing and accidentally taking more or less than one meant to take)

                        Originally posted by Grizz View Post
                        A friend is taking 20,000 IU Vit D3 daily. His doctor told him that he could not overdose on Vit D3
                        This is just STUPID.

                        so advised taking a large dosage every day to be certain of getting enough. He has been doing this for 2 years now, and has not noticed any ill effects. He laughed at me when I suggested he get his blood tested for Vit-D levels.
                        While we know that most of the acute toxicity of D is associated with levels over 200 ng/mL, between 100 ng/mL and 200 n/mL lies an area we just don't know that much about.

                        What do we know?

                        Through sun exposure alone, we can't get above 100 ng/mL (and really over 80 ng/mL). Since nature/evolution worked on that system for, oh, a few million years, I'd go with those numbers as the upper limit of what is acceptable.

                        20,000 IU will, for the vast majority of people, raise levels significantly above 100 ng/mL and toward 150 ng/mL or more. I have a friend here who is taking 10,000 IU daily and maintaining 140 ng/mL. I see it as very unwise.

                        Originally posted by racingsnake View Post
                        I am not yet convinced that there may not be other issues with constantly high blood levels.
                        I agree. When looking at the *well* done vitamin D science, there appears to be only benefit from maintaining levels around 65 ng/mL (162 nmol/L). Maintaining levels above that may not be such a good idea. Maintaining levels above 80 ng/mL (200 nmol/L) is likely a bad idea except in a few cases as outlined by Cannell - and even then it's just his theory - no evidence to back it up.

                        At $65, testing is accessible to most people. There is no reason not to do it.



                        iherb referral code CIL457- $5 off first order

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                        • #13
                          Is it possible that high D supplementation could lead to A deficiency?

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                          • #14
                            Originally posted by Hilary View Post
                            Is it possible that high D supplementation could lead to A deficiency?
                            Remember, we're not talking about *high* D supplementation. Ever. Or at least I'm not. I'm only ever talking about levels of D supplentation that physiologically appropriate based on D levels we could achieve through sun.

                            The common problem is the opposite: excessive A intake highlighting an actual D deficiency or even creating a 'relative' deficiency where there isn't an actual deficiency.

                            But as long as you're taking *appropriate* D doses to maintain/support optimal D levels *and* you're ingesting sufficient A from food or supplements, you won't have a problem.

                            I'm finding that my sweet spot (after 7 years supplementing both), appears to be a 1:6 ratio of A to D.



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                            • #15
                              Sorry, yes, I do get what you're saying. Rephrase - is it possible that by taking 6600IU D daily, at 134lb, I might be causing myself problems?

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