Contrary to what some researchers and doctors have recommended, there???s no evidence that raising blood levels of 25D above 50 ng/mL is beneficial, and there???s some evidence that it may cause harm. Studies show that bone mineral density peaks at 45 ng/mL and then falls again as 25D levels rise above 45. Other studies have shown that the risk of kidney stones and CVD increase with high 25D levels, due to elevated serum calcium levels that accompany excess vitamin D.
Yet, others promote high levels of 25D in excess of 50. Someone else on here recently promoted 25D to be ideal when it's between 70 and 100 ng/mL.
What's the evidence that there are benefits to raising 25D above 50, and what other evidence is there that going beyond 50 is either not beneficial, or outright worse for you?
asked byWyldKard (1906)
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on September 18, 2011
at 12:00 AM
Vitamin D increases the absorption of dietary Ca (via the CaT1 duodenal epithelial calcium channel) and Mg. http://www.ncbi.nlm.nih.gov/pubmed/477243 (Something to note is that magnesium absorption rises, but so does magnesium excretion). If you couple this with a high-calcium diet (the SAD) and a deficiency in retinol, K-2 etc., you could very well increase your serum calcium levels into the danger range and calcify your soft tissues and eventually cause a heart attack. If you eat a paleo diet, or even if you eat a SAD-level of calcium with dairy/supplements but get enough of the other fat solubles, you'll just build strong bones and teeth.
Something to consider is that most of us (especially the former veg*ns) are coming to paleo with much weaker bones and teeth than we would otherwise have. If you'd like to accelerate the mineralization process, you may want to overshoot for a bit.
That all said, because I don't weigh very much, 5000IU through last winter got me to 85ng/mL. This winter I'm going to take 4000IU/day. I'm also going to split up the dose into smaller parts just in case.
on September 17, 2011
at 11:44 PM
I've been on/off vitamin D since 2008 when dx'd w/ deficiency -- for my whole life I had seasonal affective d/o in the winter with major blues since my teens, bronchitis, mild tinnitus (ears ringing) and RAD asthma. Once on vitamin D, I stopped all inhalers (which were worthless for the most part) and my mood was 200% better in the winters. I found that any level < 60 ng/ml would trigger asthma with a cold, plus more frequent colds. My kids are on D and off inhalers and now rarely get sick as well.
Sunlight -- esp noon time with a run/sprint or long run -- gives me a high just like when I initially supplemented, me but since I am dark-skinned I wonder how much of the melanain actually shuts down the vitamin D conversion in the skin? I suspect a lot is blocked. I was diagnosed w/D deficiency (19 ng/ml) at the end of summer where I was in the sun nearly daily w/my kids in a bikini (with sunscreen but no reapplication and some dips in the water/sweat).
Ancestrally we all evolved in different microniches and exposures to UVA, UVB, UVC, etc. There are SNPs, VDR polymorphisms and rare post-receptor and translational variations. I actually suspect there are also adrenal and thyroidal effects on the liver/kidney and other metabolism changes which effect intracellular 1,25OHD2 concentrations that scientists haven't elucidated. Just like drugs and low thyroid/adrenal slow liver enzymes and P450 pathways and depress the elimination of steroids and certain drugs.
I've only heard of VERY rare side effects (eg one blogger), but for the great majority a combo of ancestrally derived UV radiation/sun exposures, food sources (grub, fatty seafood, livers, animal fat, CLO, mushrooms (D2) etc), cofactors (minerals, vit A/retinoids, carotenoids, mixed tocopherols, mixed menaquinones, etc) and supplementation as needed appears to me to provide the most benefits with least downsides...
In checking out the other extreme -- I tried OD'ing once on high dose A and D (like 20k per day each) and gave myself the same symptoms of D deficiency, namely fat gain, insulin resistance and feeling 'weird' (my ears 'ring' with supra-therapeutic doses or bad deficiency). Didn't know about K2 and the depletion of other fat-soluble nutrients at the time!
To me, labs sometimes (?often) are irrelevant (like TSH without context of rT3, FT4, FT3, antibodies, etc). LIke thyroid panels and magnesium, the intracellular conc is MOST important yet we don't check this with the current $$$ and other limitations.
EDIT: Though I love medical science, the limitations are that they are studies done on poor lab rats (humans) who are probably on the SAD, high fiber, sunlight deficient/indoor, fermented food/K2-deficient. How can we extrapolate bone density when they are not paleo and extremely micro- and macro-nutrient deficient? The contraindication for bioidentical D3 is sarcoidosis, a rare autoimmune condition where errant cells are producing endogenous 25OHD and/or 1,25OHD2 or other vitamin D analogues (like pheochromocytoma where errant cells are producing BP-raising, palpitation inducing adrenaline and/noradrenaline).
on September 16, 2011
at 07:27 AM
There is no proof that every day supplementation of <= 10 000 IU causes calcification on the long run. More might, however. Vitamin K is antidote used with rat poison which basically calcifies the pure creature and your cat. Kidney stones are preventable with ascorbate [stones can't form in acidic environment] and Mg [has higher affinity to oxalates].
There are other functions of Vitamin D apart from bone density - it controls 10% of your genome.
This is generally true for standard medicine - while good in acute things and baby deliveries, it fails to recognize that supplements are needed for more then to prevent deficiencies. Deficiency of any vitamin is the last stage and levels needed for optimal health are far higher. You will not feel the difference ASAP as our body is crazy adaptive machine, but it will substitute with lesser evil [plan B] in absence of resources. For instance, if you are scorbutic it will affect your blood vehicles first and body will deposit LP(a) cholesterol to prevent collagen breaks - the reasoning is its better to die 10 years later because of atherosclerosis then in a month because of internal bleeding [prolonged survival is important as we need to pass our genome and educate-it/protect it but longevity isn't].
I wouldn't be too much concerned about lower levels. My level is 35 and I wasn't seek in 3 years, not a single caugh, except 1 day virus. If you synergies nutrients you need lesser levels of all. If you give all your hopes to D, then you better boost it up.
on September 15, 2011
at 10:26 PM
I've heard anecdotal accounts of people not catching cold once their Vit D-3 started going up above 50. I haven't heard of any negative consequences from those around me but I'm aware of the claims of kidney stones and heart arrythmia. I have been as high as the mid-90s and experienced no side effect.
But, if you're supplementing at 10,000 or 5,000 iu, it does amount to a very potent, isolated nutrient in a single dose. I do wonder what the implication of this is, since Vitamin D supplementation is a recent thing in human history. Before the 1990s, we only got D-3 through sunlight.
Why not just be slightly above 50? Like around 65 or so but not above 75? I'm now at 50 and I do plan on increasing my dose just a little, since I cut back on my dose (2,000 every other day) during the summer.
on September 15, 2011
at 09:45 PM
My n=1 "evidence" is that at 91 ng/ml (tested after one year of supplementing 8,000 IUs) I haven't been sick with a virus in almost 2 years.
I have lowered my dose to 6,000 IUs and will be testing again very soon. My intention is to stay at or above 80 ng/ml.
on September 19, 2011
at 12:36 AM
Here is a good primer on vitamin D (and K2) with citations. The risk for kidney stones and cad with therapeutic replacement with bioidentical vitamin D (not D2 or drug analogues) is rare in the literature, that I could find. In fact, my sister passed 2 kidney stones and it turns out vitamin D deficiency is A RISK FACTOR FOR KIDNEY STONES (esp gluten intolerance folks). T-W-O PAINFUL KIDNEY STONES.
"As noted in Part I of this review, the body's ability to utilize cholecalciferol in the numerous roles played by the vitamin D endocrine system is not optimized until blood levels of 25(OH)D are ???40 ng/ml (98 nmol/L). Not until this level is the Vmax, of the 25-hydroxylase enzyme achieved (i.e., are all enzyme sites saturated). Below this level, chronic substrate deficiency prevents full actualization of the myriad benefits of vitamin D.82 For some individuals, supplementation of vitamin D3 in the range of 5,000 ??? 10,000 IU/day may be necessary to reach and maintain these blood levels, which underscores the concomitant need for adequate supplies of vitamin A as well as vitamin K. The National Institutes of Health has set the RDI for vitamin A at 3,000 IU for males ??? 14 years and 2,310 IU for females ??? 14 years, and the tolerable upper limits for retinols in both men and women at 10,000 IU."
Calcium and all biochemical markers were all normal in nursing home residents provided 5000 IU (125 mcg) vitamin D3 + calcium baked in a bread bun daily for 1 year. Bone mineral density (BMD) improved for both hip and lumbar spine at the end of 1 year. [There is another study which used 5000 IU but I can't find it w/improved BMD, PTH and 25OHD.] It is a shame is someone is taking a bisphosphonate for osteopenia/-porosis when K2/Mag/Ca/D3 work better in the medical literature without causing spontaneous non-traumatic fractures, atrial fibrillation and esophageal ulcerations that are linked to these HEDIS-mandated drug class for secondary fracture prevention.
on September 16, 2011
at 03:16 AM
I came into this past summer with levels in the 60s after a winter of as much sun exposure as possible, 5-10,000 iu/day supplementing, and some tanning bed time.
Haven't supplemented all summer and got a pretty good amount of full body sun exposure. Just got my blood tests done and I'll find out on tuesday what my D level is.
For me this will be an important number. Starting out with a healthy level, whatever the sun gave me naturally will be a good number for me to strive towards via supplementation during the winter.
(I'll definitely add the results here when I get it)