114 replies to this topic

[FunkOdyssey]

I was already considering raising my daily vitamin D intake to 2000iu, and now this:

Review finds current vitamin D recommendations insufficient to achieve healthy blood levels

A review published in the July, 2006 issue of the American Journal of Clinical Nutrition which sought to determine the optimal serum levels of the major circulating form of vitamin D [25(OH)D] for several health outcomes concluded that it would be necessary to consume at least 1000 international units of vitamin D per day to elevate blood serum levels in half the adult population to 75 nanomoles per liter, the minimum level that the researchers found to be advantageous for helping to preserve normal bone mineral density and lower extremity function, and aiding in the prevention of periodontal disease, falls, fractures, and colorectal cancer. Although there is evidence for vitamin D in preventing other diseases such as multiple sclerosis, tuberculosis, insulin resistance, osteoarthritis, hypertension, and cancers other than colorectal cancer, the authors did not include these diseases in the current review.

H. A. Bischoff-Ferrari of Harvard School of Public Health in Boston and University Hospital Zurich in Switzerland, along with colleagues at Harvard and Tufts University evaluated clinical trials and meta-analyses involving vitamin D and each of the selected health outcomes. They concluded that the most desirable serum levels of vitamin D began at 75 nanomoles per liter (30 nanograms per milliliter), and optimal levels are between 90 and 100 nanomoles per liter. These levels cannot be reached by most individuals with the current recommended intakes of 200 international units per day for younger adults and 600 international units per day for older adults. To bring vitamin D concentrations in at least 50 percent of the population up to optimal levels, the authors recommend at least 1000 IU vitamin D per day, and they remark that 2000 IU per day may be a safe recommended daily allowance.

“On the basis of this review, we suggest that, for bone health in younger adults and all outcomes in older adults, including antifracture efficacy, lower-extremity strength, dental health, and colorectal cancer prevention, an increase in the current recommended intake of vitamin D may be warranted,” the authors conclude. “Given the low cost, the safety, and the demonstrated benefit of higher 25(OH)D concentrations, vitamin D supplementation should become a public health priority to combat these common and costly chronic diseases.”

[syr_]

Uhm I take 1000 IU in AOR essential mix. During the summer I get enough sunlight to not need more but for winter I'm thinking also to go to 2000 IU.

[Matt]

I get 500 IU (d3) from 50% of Essential Mix and 1000 IU from Vitamin D3 supp.

Studies have shown you can go well above 1000 IU and be safe in the long term.

[xanadu]

Or just get a few minutes exposure to sun every day and you'll be alright. I've heard that 15 minutes a week is more than adequate for most people. If you also take a supplement, where is the danger? I guess people who stay indoors all day might be at risk and may need more supplementation. Just going out to and from the car, to and from work, from the mall and so on should do it.

[FunkOdyssey]

Here's the abstract of this study:

Am J Clin Nutr. 2006 Jul;84(1):18-28.  Links
Estimation of optimal serum concentrations of 25-hydroxyvitamin D for
multiple health outcomes.Bischoff-Ferrari HA, Giovannucci E, Willett
WC, Dietrich T, Dawson-Hughes B.
Department of Nutrition, Harvard School of Public Health, Boston, MA.

Recent evidence suggests that vitamin D intakes above current
recommendations may be associated with better health outcomes. However,
optimal serum concentrations of 25-hydroxyvitamin D [25(OH)D] have not
been defined. This review summarizes evidence from studies that
evaluated thresholds for serum 25(OH)D concentrations in relation to
bone mineral density (BMD), lower-extremity function, dental health,
and risk of falls, fractures, and colorectal cancer. For all endpoints,
the most advantageous serum concentrations of 25(OH)D begin at 75
nmol/L (30 ng/mL), and the best are between 90 and 100 nmol/L (36-40
ng/mL). In most persons, these concentrations could not be reached with
the currently recommended intakes of 200 and 600 IU vitamin D/d for
younger and older adults, respectively. A comparison of vitamin D
intakes with achieved serum concentrations of 25(OH)D for the purpose
of estimating optimal intakes led us to suggest that, for bone health
in younger adults and all studied outcomes in older adults, an increase
in the currently recommended intake of vitamin D is warranted. An
intake for all adults of >/=1000 IU (40 mug) vitamin D
(cholecalciferol)/d is needed to bring vitamin D concentrations in no
less than 50% of the population up to 75 nmol/L. The implications of
higher doses for the entire adult population should be addressed in
future studies.

PMID: 16825677 [PubMed - in process]

[DukeNukem]

I've been around 1500IU daily for 18 months, not including sunshine. If I ever had cancer, I'd double that.

[tham]

Vitamin D3 also has applications in the prevention
and treatment of congestive heart failure, based
largely on German studies :


http://www.ncbi.nlm....l=pubmed_docsum

http://www.ncbi.nlm....l=pubmed_docsum

http://www.ncbi.nlm....l=pubmed_docsum

http://www.ncbi.nlm....l=pubmed_docsum

http://www.ncbi.nlm....l=pubmed_docsum

http://www.ncbi.nlm....l=pubmed_docsum

[Athanasios]

I am at 1600IU, interesting that a few of you have chosen dosages at about this range. If I lived in the north, I live in Texas, I definitely would up it from what I am currently taking.

Duke have you had any testing done that showed your levels after this supplementation?

[olderbutwiser]

Or just get a few minutes exposure to sun every day and you'll be alright. I've heard that 15 minutes a week is more than adequate for most people. If you also take a supplement, where is the danger? I guess people who stay indoors all day might be at risk and may need more supplementation. Just going out to and from the car, to and from work, from the mall and so on should do it.

That has been conventional "old wive's tale" wisdom. It appears to not be true for a larger segment of the population, at least seasonally. There was a fairly lengthy discussion on D3 on the yahoo health group "morelife"

Post with citations

Web based calculator for Sun exposure D3 production

I live in Alaska and work in total solar darkness for 4 months out of the year so I am probably at the most extreme variation in D3 production. I take around 4000i.u. D3 in winter (multi + Carleson's cod liver oil) and 2000i.u (contained in multi) in the summer. I can definitely tell a difference in vulnerability to flu with/without sups. Two years ago I began seasonally alternating between Carleson's cod liver oil and Carleson's fish oil to vary my D3 intake.

OBW

[Athanasios]

I posted a few links to papers on vit D here:

http://www.imminst.o...=0

Here it is for discussion:

Deficiency in vit D is high, and it comes at a high cost. The vitamin is super cheap and safe. I think we have more to learn on the benefits of this vitamin, even though there are mountains of research already. I am truly surprised at how little coverage D3 gets. I currently get 1600iu from my multi and vit d supplement. I live in texas.

From PMID: 16251641

Vitamin D deficiency is now recognized as an epidemic in the United States. ...There is mounting scientific evidence that implicates vitamin D deficiency with an increased risk of type I diabetes, multiple sclerosis, rheumatoid arthritis, hypertension, cardiovascular heart disease, and many common deadly cancers. Vigilance of one's vitamin D status by the yearly measurement of 25-hydroxyvitamin D should be part of an annual physical examination.

http://jn.nutrition..../full/135/2/332

They defined vitamin D insufficiency as a serum 25(OH)D of ≤20 µg/L (50 nmol/L), and divided their subjects into 4 age groups, 18–29 y, 30–39 y, 40–49 y, and ≥50 y. Serum 25(OH)D was measured in 142 subjects at the end of summer and in 165 subjects at the end of winter. A high incidence of vitamin D insufficiency was found (Table 2). A significant (P < 0.001) difference was demonstrated between measures of 25(OH)D after summer (35 ± 10 µg/L) and after winter (30 ± 10 µg/L). Vitamin D insufficiency was more prevalent in all age groups after winter and averaged 30% after winter and 11% after summer. Somewhat surprisingly, the eldest group was least likely of the groups to have insufficiency and the authors felt this is likely explained by subjects’ use of a multivitamin containing 400 IU of Vitamin D. Multivitamin use was significantly inversely associated with vitamin D insufficiency in the after summer and the after winter groups.

http://jn.nutrition..../full/135/2/317

The data show that for every 40 IU of vitamin D intake, circulating 25(OH)D increases by 0.70 nmol/L (0.28 µg/L) over 5 mo on a given regimen. A steady state appears to be achieved after ~90 d on each dose tested (23,38). Thus, doses of 400, 1000, 5000, and 10,000 IU/d for 5 mo will result in theoretical increases in circulating concentrations of 7, 17.5, 70, and 175 nmol 25(OH)D, respectively. Again, no adverse events were noted.

[Matt]

You can go far above 2000, 5000, 10,000 and even higher on D3 for long time, without any problems according to many studies.

[syr_]

You can go far above 2000, 5000, 10,000 and even higher on D3 for long time, without any problems according to many studies.

Right, but if that is so, then why aren't many people here on doses above 2000, and why do I see a hesitation to go above 2000?

Cost in my case.

[FunkOdyssey]

I've been taking 4000iu daily for at least six months now (I need to update my regimen thread). [thumb]

[Athanasios]

From all of the research that I have been able to find, it seems that 4,000 - 10,000 IU of Vitamin D is the ideal dose. I can find no examples of hypercalcemia at chronic doses below 40,000 IU. However, people here seem to be reluctant to go above 2,000 IU. Is this superstition, or is there data to suggest a risk at doses above 2,000?

From your research, what have you found to be the optimum level? How many IU would it take to reach that optimum level without any sun at all? How many IU do you think the average caucasian person under 50 should take to be in the optimum level with regular sun exposure?

[Athanasios]

You want 75-160 nmol/L 25(OH)D circulating in your blood.

I wouldnt hesitate to say 100-250, but over 4kIU does not seem to be needed, with the exception of someone like the submarine workers. Very few people would land below 100nmol/L with 4kIU. Why go higher?

I do like the idea of ensuring levels over 100, whereas I have chosen my dose on the 80 mark. I will up my intake to 2600IU. This dose would still make it unlikely that i go much above the 250 mark, but still ensure over 100.

[zarathustra]

I recommend to combine vitamin d with k2:

Med Hypotheses. 2006 Dec 2

Vitamin D toxicity redefined: Vitamin K and the molecular mechanism.

Masterjohn C.
Weston A. Price Foundation, 4200 Wisconsin Ave., NW, Washington DC 20016, United States.

The dose of vitamin D that some researchers recommend as optimally therapeutic exceeds that officially recognized as safe by a factor of two; it is therefore important to determine the precise mechanism by which excessive doses of vitamin D exert toxicity so that physicians and other health care practitioners may understand how to use optimally therapeutic doses of this vitamin without the risk of adverse effects. Although the toxicity of vitamin D has conventionally been attributed to its induction of hypercalcemia, animal studies show that the toxic endpoints observed in response to hypervitaminosis D such as anorexia, lethargy, growth retardation, bone resorption, soft tissue calcification, and death can be dissociated from the hypercalcemia that usually accompanies them, demanding that an alternative explanation for the mechanism of vitamin D toxicity be developed. The hypothesis presented in this paper proposes the novel understanding that vitamin D exerts toxicity by inducing a deficiency of vitamin K. According to this model, vitamin D increases the expression of proteins whose activation depends on vitamin K-mediated carboxylation; as the demand for carboxylation increases, the pool of vitamin K is depleted. Since vitamin K is essential to the nervous system and plays important roles in protecting against bone loss and calcification of the peripheral soft tissues, its deficiency results in the symptoms associated with hypervitaminosis D. This hypothesis is circumstantially supported by the observation that animals deficient in vitamin K or vitamin K-dependent proteins exhibit remarkable similarities to animals fed toxic doses of vitamin D, and the observation that vitamin D and the vitamin K-inhibitor Warfarin have similar toxicity profiles and exert toxicity synergistically when combined. The hypothesis further proposes that vitamin A protects against the toxicity of vitamin D by decreasing the expression of vitamin K-dependent proteins and thereby exerting a vitamin K-sparing effect. If animal experiments can confirm this hypothesis, the models by which the maximum safe dose is determined would need to be revised. Physicians and other health care practitioners would be able to treat patients with doses of vitamin D that possess greater therapeutic value than those currently being used while avoiding the risk of adverse effects by administering vitamin D together with vitamins A and K.

PMID: 17145139 [PubMed - as supplied by publisher]

Also check out this article:
http://www.westonapr...n-d-safety.html

[opales]

You want 75-160 nmol/L 25(OH)D circulating in your blood.

I wouldnt hesitate to say 100-250, but over 4kIU does not seem to be needed, with the exception of someone like the submarine workers. Very few people would land below 100nmol/L with 4kIU. Why go higher?

I do like the idea of ensuring levels over 100, whereas I have chosen my dose on the 80 mark. I will up my intake to 2600IU. This dose would still make it unlikely that i go much above the 250 mark, but still ensure over 100.

Why do you suggest 100-250, the absract cited by Funk states explicitly:

For all endpoints, the most advantageous serum concentrations of 25(OH)D begin at 75
nmol/L (30 ng/mL), and the best are between 90 and 100 nmol/L (36-40 ng/mL).

[opales]

Why do you suggest 100-250, the absract cited by Funk states explicitly:

You need to keep better track of units. 100-250 mcg vitamin D will bring about 75-160 nmol/L of 25(OH)D.

I'm cribbing directly from Vieth who calls for that dosage to obtain "optimum" levels of circulating 25(OH)D.

I am not sure what you mean by keeping track of units, the abstract quote referred to blood concentrations (nmol/L) as did your and crnorwood's comments?

Note that the reference was based on review of literature (thus on pool of studies), I am not sure where you (or Vieth) got your number. Anyway, the article was published in a prestiguous journal having been through peer-review which in my book overrides unofficial/unpublished opinions. Also, the 90-100nmol/L is more specific than 75-160 nmol/L, and in the abstract they say that "the most advantageous serum concentrations of 25(OH)D begin at 75 nmol/L (30 ng/mL)" which is actually consistent with Vieth's comment. Maybe 75-165 nmol/L is "adequate" target to aim for whereas 90-100 nmol/L is optimum?

Also you said earier on that there is not real research on what is optimum, only what is needed to avoid deficiency, but this review explicitly takes a stance on what is optimum. What is interesting that (according to the abstract, don't have time to plough through the full text right now) they found the optimum for all different endpoint markers to be 90-100 nmol/L which is actually remarkable as the endpoints were as differing as "bone mineral density (BMD), lower-extremity function, dental health, and risk of falls, fractures, and colorectal cancer" (ok, most are probably somehow related to bone health except for colorectal cancer).

Edited by opales, 19 January 2007 - 03:29 PM.

[Athanasios]

Why do you suggest 100-250, the absract cited by Funk states explicitly:

For all endpoints, the most advantageous serum concentrations of 25(OH)D begin at 75
nmol/L (30 ng/mL), and the best are between 90 and 100 nmol/L (36-40 ng/mL).

I don't think opales is misunderstanding me. I was saying 100nmol/L to 250nmol/L. I was saying you want 100nmol/L as a minimum and 250nmol/L as a max. From what I have read, to get all of the benefits, you want 100nmol/L. In that sense it is "optimum".

From: http://jn.nutrition..../full/135/2/317

In sun-rich environments where clothing or cultural practices do not prevent sun exposure, circulating 25(OH)D ranges from 135 to 225 nmol/L (54–90 µg/L) (1,14,15).

and

However, circulating levels of 25(OH)D that define optimal vitamin D status or repletion and toxicity—hypervitaminosis D—remain blurred. I have arbitrarily set the toxic level at 250 nmol (100 µg/L), which is a conservative estimate, because true vitamin D toxicity is well beyond this concentration, as shown in a recent study that observed no harmful effects with 25(OH)D levels of 250 nmol (23).

From the study that it is referring to
http://www.ajcn.org/...0998f9ae619ae4b

Note that, in our study, 20 wk of supplementation at 5500 and 11 000 IU/d, starting from a status of relative vitamin D repletion, produced no elevation of serum calcium above the upper limits of normal in any subject. Note also that the highest mean 25(OH)D3 values reached were {approx}160 and {approx}220 nmol/L, respectively.

With these two pieces of info, I also am setting the arbitrary mark of 250nmol/L.

I want to take an amount the ensures I will not dip below 100nmol, but also I do not want an amount that would take me over 250nmol. Which is the reasoning for my dosage.

Edit: If you want to be more conservative, set the max mark at 225nmol/L.

Edited by cnorwood19, 19 January 2007 - 06:20 PM.

[boily]

Here is a presentation by Reinhold Vieth which details his reasons
for higher Vitamin D level requirements and does so in lay terms.

I just watched the presentation and it builds a massively strong case for vitamin D supplementation! Worth listening to. So strong in fact I went out and bought some D3 1000UI gels, they are suprisingly cheap! I'll be conservative and pop 2 a day. Add in my orthocore 6 caps a day I'll be supping about 2600UI a day from now on.....

[medievil]

http://www.vitamindcouncil.com/

wow, look at all the abstracts at this site
gonna order some vitamin d too

[chrisp2]

Here is a presentation by Reinhold Vieth which details his reasons
for higher Vitamin D level requirements and does so in lay terms.

I just watched the presentation and it builds a massively strong case for vitamin D supplementation! Worth listening to. So strong in fact I went out and bought some D3 1000UI gels, they are suprisingly cheap! I'll be conservative and pop 2 a day. Add in my orthocore 6 caps a day I'll be supping about 2600UI a day from now on.....

I'm already taking 2000IU (in addition to dietary, and what is in some of the other supps I take). I was recently tested at 17 ng/ml, which is quite low (and hence the addition of the 2000 IU)

Anyway it was not easy to watch - horrible network performance and bad buffering by the server (don't know precisely where the problem is there - but I have never had such streaming problems before)

Thanks to the OP of that link - great stuff.

Although there is conflicting thoughts out there... I found this from a link from Dr. Mercola. This person appears to have done a ton of Vitamin D research too - but not peer reviewed or even published yet.

http://sunlightandvi...com/samples.htm

[medievil]

http://video.google....4..."vitamin d"

Mercola has a video on this issue, too. Similar conclusion
but his focus is on the sun.

altough he is right on this one, mercola is a quack, and has flawed articles on mobile phones and microwaves

[chrisp2]

http://video.google....4..."vitamin d"

Mercola has a video on this issue, too. Similar conclusion
but his focus is on the sun.

altough he is right on this one, mercola is a quack, and has flawed articles on mobile phones and microwaves

I do have some level of respect for him - but it is substantially mitigated when he goes and claims the bird flu is a hoax.

Considering there has been (very) limited human-human spreading of the disease, and the very high mortality rates... Should it ever mutate into something that does easily pass from one person to another... Bad things will happen... For the entire world.

[health_nutty]

I'm already taking 2000IU (in addition to dietary, and what is in some of the other supps I take).  I was recently tested at 17 ng/ml, which is quite low (and hence the addition of the 2000 IU)

http://sunlightandvi...com/samples.htm

Wow, I'm amazed that 2000IU only generated 17ng/ml! How long were you at that dosage before you got tested? Do you get any significant amount of sun? I'm a little concerned because I figured I was covered taking 2000IU extra (in additionto the 400IU in my multi). A couple of months ago I thought I was covered with 400IU but the mound of evidence convinced me I needed to up my dosage.

[TheodoreTried]

http://www.npicenter...17482&zoneid=28

Another news report suggesting a need to increase the UL.

[shuffleup]

I don't do the wiki thing but someone misinterpreted the info from the Merck writeup, on wikipedia:

"The exact long-term safe dose of vitamin D is not entirely known, but dosages up to 60 micrograms (2,400 IU)/day in healthy adults are believed to be safe.[8] The U.S. Dietary Reference Intake Tolerable Upper Intake Level (UL) of vitamin D for childern and adults is 50 micrograms/day (2000 IU/day). In adults, sustained intake of 2500 ìg/day (100,000 IU) can produce toxicity within a few months, and, if taken for years, as little as 50 to 75 ìg/day (2000 to 3000 IU) can produce toxicity.[2] For infants (birth to 12 months) the tolerable UL is set at 25 micrograms/day (1000 IU/day), and vitamin D concentrations of 1000 ìg/day (40,000 IU) in infants has been shown to produce toxicity within 1 to 4 months."


http://en.wikipedia....n_D#_note-Merck

[chrisp2]

I'm already taking 2000IU (in addition to dietary, and what is in some of the other supps I take).  I was recently tested at 17 ng/ml, which is quite low (and hence the addition of the 2000 IU)

http://sunlightandvi...com/samples.htm

Wow, I'm amazed that 2000IU only generated 17ng/ml! How long were you at that dosage before you got tested? Do you get any significant amount of sun? I'm a little concerned because I figured I was covered taking 2000IU extra (in additionto the 400IU in my multi). A couple of months ago I thought I was covered with 400IU but the mound of evidence convinced me I needed to up my dosage.

No, you misunderstood my cryptic post

I tested at 17 ng/ml. This being quite low, I added 2000 IU daily of quality D3.

[health_nutty]

Oh, Oh, thanks for clearing that up. It should have been obvious what you meant (in hindsight)

[Aegist]

http://www.insinc.co...tvnetplayer.htm

Here is a presentation by Reinhold Vieth which details his reasons
for higher Vitamin D level requirements and does so in lay terms.

Well, I finally just watched the entire presentation and WOW that was good. Yeah, I'm sold too. I'll start taking 2,000 per day as soon as I get some.