Vitamin D - Estimated Intakes

[GeneGnomeX]

There has been much discussion on vitamin D lately, and a lot of random dose suggestions. Here is a recent one that shows large dose response differences (estimations) between studies.

The following is a summary from the following study:

Cashman KD, et al. Estimation of the dietary requirement for vitamin D in healthy adults. American Journal of Clinical Nutrition. 2008.

-Vitamin D deficiency is defined as a serum or plasma 25-OHD concentration of <10-25 nmol/L.
-In the UK, 25 nmol/L is the low threshold.
-Research has suggested that the low limit be increased
-Less than 50 nmol/L may be associated with a greater risk for nonskeletal chronic diseases

Methods

• n=245 (Cork, Ireland and Coleraine [lat=51 degrees N], Northern Ireland (UK) [lat=55 degrees N])
• white men and women aged 20-30 and 30-40
• t=22 weeks (October 2006-March 2007)
• exclusion criteria: consumption of vitamin D supplements for 12 weeks before study or if a winter vacation was planned (cutaneous synthesis), mental illness, hypercalcemia, intestinal malabsorption syndrome, excessive alcohol consumption, medications that interfere with D metabolism, or pregnancy plans
• double-blind, placebo-controlled
• subjects randomly assigned 0, 5, 10, or 15 micrograms (0, 200, 400, 600 IU)
• sun exposure recorded
• attrition: 24
• Vit D3 (cholecalciferol)

Results

• Male average dietary intake: D-152 IU Calcium-1128mg vs female: D-132 IU Calcium-803mg
  Subjects who reported summer sun exposure had a higher baseline serum 25OHD concentration compared to those who reported avoiding or sometimes having exposure (82.4 nmol/L vs 65.2 nmol/L.)
• Total vitamin D intake (diet plus supplemental vitamin D) increased in a dose-related manner with supplementation (4.4 ? 3.6, 9.1 ? 2.4, 13.9 ? 2.0, and 19.2 ? 3.1 ?g/d in the placebo and 5, 10, and 15 ?g vitamin D/d groups, respectively
• Slope relating intake and serum 25OHD = 1.96 nmol/L per 40IU (though another study reported only .70 nmol/L per 40IU)
• "Using mathematical modeling of the vitamin D intake?status data, we estimated that the vitamin D intakes that maintained serum 25(OH)D concentrations >25 nmol/L in 90%, 95%, and 97.5% of the 20?40-y-old adults were 2.7, 5.9, and 8.7 ?g/d, respectively." (that is 108, 236, 348 IU/day)
• "Data on sun preference also were incorporated into the model; the vitamin D intakes that maintained serum 25(OH)D concentrations of 25 nmol/L in 97.5% of the sample were 7.2, 8.8, and 12.3 ?g/d in those who reported often having sunshine exposure, those who sometimes had sunshine exposure, and sunshine avoiders, respectively" (288, 352, 492 IU/day)
• "The vitamin D intakes that maintained serum 25(OH)D concentrations above 2 other commonly suggested cutoffs in 97.5% of the sample were 26.1, 27.7, and 31.0 ?g/d (for 50 nmol/L) (1044, 1108, 1240 IU) and 38.9, 40.6, and 43.9 ?g/d (for 80 nmol/L) in those who reported often having sunshine exposure, those who sometimes had sunshine exposure, and sunshine avoiders, respectively." (1556, 1624, 1756 IU/day)
• Another study (Heaney et al.) estimated that 4560IU/day was necessary to maintain above 80nmol/L in 97.5% of subjects, vs this study only (an estimated) 1640 IU/day was needed. Though, few subjects obtained greater than 80nmol/L, so future studies will need to utilize higher doses to confirm the estimated intakes.

[Alphy]

So its saying 2000IU/day is plenty?

Others recommend 4000-5000IU/day. Some take much more than that. Whats the most backed theory?

[Littleman]

I would think the dosage would be based on different factors, some of those being age, exposure to sunlight, sex, where people live, etc... Also, is the plenty you are referring to plenty for a normal person or someone with a Vit. Deficiency or Insufficiency?

The most recent 2 articles I've read on uptodate call for avg Vit D intake of 800-1000 IU/day. The treatment for deficient or insufficient people can be up to 50,000 IU/week for the 1st 6 weeks - after which they are then brought back to the 800-1000 IU/day level.

The upper daily limit of Vit D in men and women 9-1,000,000 yrs old is 50 mcgs/day, according to "Daily Reference Intake reports of the Food and Nutrition Board, Institute of Medicine. Available at: www.nap.edu".

Since there is 1 mcg in 40 IU - the UL should be around 2000 IU/day. It is possible to use higher doses to treat certain conditions, however most docs take this back down when their patients Vit D levels get back into the normal range. The reason for this is Vitamin D intoxication which can lead to - Hypercalcemia, hypercalciuria (calicum stones), polydipsia, polyuria, confusion, anorexia, vomiting, and bone demineralization.

I would think that anyone taking doses as high as 4-5k on a regular basis is bound to have some major problems with this. So I would avoid that for sure. And I would definitely be going to my doc to have him check my Vit D levels if I was on long-term supplementation just to make sure everything is alright.

[Alphy]

Sounds like 2000IU is a good safe place to start. I have only done 400-800IU/day for some time. I seem to get less and less time outdoors so I thought that its very possible I could up the dosage, esp with all the benefits that are starting to be realized regarding D.

[dirkwright]

I would think the dosage would be based on different factors, some of those being age, exposure to sunlight, sex, where people live, etc...

Yeah, take plenty in the winter, less in the summer, assuming you're exposed to the sun in summer. I take a total of about 2,000 IU and feel great. I have not been sick this winter so far inspite of traveling a lot.

[Littleman]

Honestly man, I would start at less than 2000IU/day. This is approaching the end of the upper limit. The best thing to do is to go see a doc first and get some blood work, then get on a steady dose for about 6 wks, then go see a doc and get the blood work again. That way you know exactly what is going on and you can adjust your doses accordingly. But if you aren't going to do that I would start at a smaller dose.

[Loomy]

good thread. if you were unable to understand the original post, I'll simplify it for you: if you're under 40 years old and go outside sometimes, 1000 iu is the max you should take daily.

[dirkwright]

good thread. if you were unable to understand the original post, I'll simplify it for you: if you're under 40 years old and go outside sometimes, 1000 iu is the max you should take daily.

Well, I'm 49 and spend most of my time indoors, glued to a computer. When I move to Sweden in 6 years, I'll certainly be taking vitamin D in the dark months.

I know I should get blood tests done, but it's expensive and a hassle too.

[labradarep]

I currently take 1000 IU/day. I am going to bump it up to 2000 IU and see if there is a noticable effect. I live in Canada & here they recommend 1000 IU/day.( RDA) I want ODA.

[Lager1]

I drink a gallon and a half of milk every day, am I getting enough vitamin D?

[LactoseTolerant]

Others recommend 4000-5000IU/day. Some take much more than that. Whats the most backed theory?

I've heard that 5000IU is bordering the toxicity level.

I drink a gallon and a half of milk every day, am I getting enough vitamin D?

A cup of milk = 45% of RDA for vit. D. I'm not sure what the current RDA is.

[JacktheHero]

I've heard that 5000IU is bordering the toxicity level.

A cup of milk = 45% of RDA for vit. D. I'm not sure what the current RDA is.

Just because you have heard some random (maybe even FDA approved, but still) misinformation about vitamin D doesn't make it true.

Littleman, what the fcuk? Some of your comments were sound, but others were in the realm of vitamin D toxicity hysteria: "anyone taking doses as high as 4-5k on a regular basis is bound to have some major problems with this."
Please no such claims without evidence, I've provided plenty of evidence to the contrary in the other vitamin D thread.
As the vitamin D researcher Vieth put it: "If there is published evidence of toxicity in adults from an intake of 250 ug (10,000 IU) per day, and that is verified by the 25(OH)D concentration, I have yet to find it."
Yes, the challange by Dr. Vieth is up to anyone, including you Littleman.

I am constantly presenting evidence in support of sensible vitamin D supplementation, as supported by the best vitamin D researchers worldwide: Dr Holick, Cannell, Vieth, Zittermann, Hollis, et al. So let me reiterate some of the basics.

Toxicity would depend on so many things, body weight, additional sun exposure. Are we talking chronic intakes or short term intakes? Real toxicity (disturbances of calcium homeostasis) or maybe a small long term impact on mortality?
Therefore there can be no meaningful or definite RDA and UL for supplemental vitamin D! It's impossible. Sorry, but blood levels are the only way to go - the only alternative is complete control of sun exposure and a feel for your body, e.g. initial blood tests to see how you respond to vitamin D and then keep that level.

As always this is already common knowledge, even the established cardiologist Dr. William Davis, talking out of experience, agrees, dedicating a whole blog post to this absurd idea of a "vitamin D RDA".

labradarep, not necessarily. Even the Canadian Cancer Society endorses supplementation with 2000 IU, for people with low sun exposure.

So its saying 2000IU/day is plenty?

Others recommend 4000-5000IU/day. Some take much more than that. Whats the most backed theory?

No, 2000 IU is not "plenty". It's a safe, conservative starting level, for those with lowish sun exposure. What this study tells us is that any dose, which allows to keep the desired vitamin D blood levels, is sufficient. However, the variability is huge and therefore blood testing is the only reliable method to tell, not some arbitary amount of IUs/d.

The only meaningful question is, what are desired blood levels? Well, according to a recent epidemiologic study blood levels of ~35ng/mL seem to result in the lowest mortality*.
Dr. Cannell's advise is still higher ~50ng/mL, you decide. As bodybuilders you may be interested in his perspective on vitamin D for performance enhancement.

*taken from http://courses.washington.edu/bonephys/opvitD.html

[GeneGnomeX]

Great post as usual, Jack.

I've heard that 5000IU is bordering the toxicity level.

No, at this dose sunlight would be toxic.

There are limited reports of toxicity from oral supplementation, you really have to be stupid or consume it unknowingly in enormous amounts.

One case is of two men who consumed about 1,700,000 IU D3 DAILY for 7 MONTHS before serious problems were evident. This was because of an industrial error; their table sugar had large amounts of D in it.

http://www.direct-ms.org/pdf/VitDVie..._Poisoning.pdf

The conservative LD50 in humans is estimated to be over 40,000,000 IU IIRC.

[musclepeak88]

Im going to up mine to 2000 iu's.

[niktak11]

Im going to up mine to 2000 iu's.

I'm probably going to bump mine up too, 4000-5000iu in the winter should be good. Is anyone doing 5 on 2 off like with the other fat solubles?

[MikeCellucor]

2000 iu a day seems to make a difference for me. 4000iu if I am sick, and or feeling down and out.

[JacktheHero]

As bodyweight evidently seems to play a role in vitamin D toxicity, big guys, e.g. bodybuilders, should have even less of a problem with a dose of 2000 IU and up.
I believe the IOM designed RDA and UL is based on a catch 22 problem. The target blood levels are too low to be benefical (used to be ~25nmol/L, now maybe changed to ~50nmol/L as pointed out in the OP) and so any interventional studies use very low doses of vit D. Higher doses of vitamin D are still regarded as "toxic" and not tested because the lower doses are not found to provide much of a benefit, therefore a lack of interventional data on higher doses prevents them from adjusting their recommendations.

However, a committee is currently reconsidering the RDA and UL, so it would be a big mistake to point to the UL and RDA as a guidance at this moment. It may change very soon. Still the IOM committee did not invite any of the best vitamin D researchers, some of their members did not even publish peer reviewed papers on vitamin D... great, we're up for a surprise :-/

[Littleman]

Jack, I do apologize for not getting a response to your message earlier. My advise on here is ALWAYS supported by literature as I do not believe in talking out of my ass. There are several articles I used to come up with the advice I gave earlier. The problem is these articles are from uptodate and are thus not accessible unless a person pays a subscription to the website. For those of you who aren't familiar with uptodate, it is the #1 search engine used by both physicians and researchers when looking up information in medical literature.

I believe this was you quote, "Littleman, what the fcuk? Some of your comments were sound, but others were in the realm of vitamin D toxicity hysteria: "anyone taking doses as high as 4-5k on a regular basis is bound to have some major problems with this."
Please no such claims without evidence, I've provided plenty of evidence to the contrary in the other vitamin D thread.
As the vitamin D researcher Vieth put it: "If there is published evidence of toxicity in adults from an intake of 250 ug (10,000 IU) per day, and that is verified by the 25(OH)D concentration, I have yet to find it."
Yes, the challange by Dr. Vieth is up to anyone, including you Littleman"

The 4-5k IU dosage is based on the most current literature which states that 2000 IU/day is the upper limit for Vitamin D doses in the "normal" person. Thus, taking over 2x that much on a chronic basis will most likely lead to problems. I am going to post links to the 3 articles I got my information from and it would probably do you, and everyone else on here, some good to actually read through them. I am very hesitant about giving people advice over message boards b/c the things we say on here some people will take as advice from a physician without ever looking into themselves.

Enjoy the articles and let me know what you think.

[Littleman]

I had to delete the introduction part of this paper to make it fit. Please read this and if you have evidence that shows that 5000 IU/day taken for more than 12 months is safe I would love to see it. So I suppose the challenge would now be to you Jack. I don't want to take up to much space so I won't post the other 2 articles unless I need to. But I think this illustrates why I gave the advice I gave, and supports it.
Overview of vitamin D
Authors
Sassan Pazirandeh, MD
David L Burns, MD
Section Editors
Timothy O Lipman, MD
Kathleen J Motil, MD, PhD
Deputy Editor
Jean E Mulder, MD

Last literature review version 16.3: October 2008 | This topic last updated: April 28, 2008 (More)
This topic review will provide an overview of Vitamin D. Other reviews discuss specific issues related to vitamin D. (See "Metabolism of Vitamin D", see "Causes of vitamin D deficiency and resistance", see "Etiology and treatment of hypocalcemic rickets in children", see "Overview of rickets in children", and see "Vitamin supplementation in disease prevention").

CHEMISTRY ? Vitamin D, or calciferol, is a generic term, and refers to a group of lipid soluble compounds with a four-ringed cholesterol backbone.

ABSORPTION AND METABOLISM ? Sunlight and ultraviolet light photoisomerize provitamin D to vitamin D3 (cholecalciferol) in the skin; they are then bound by the vitamin D binding proteins (DBP) and transported via blood to target organs for metabolism and activity (show figure 1). (See "Metabolism of vitamin D").
In addition to production in the skin via photoisomerization, intestinal absorption is the other major source of vitamin D. As part of the diet, vitamin D is found in fortified milk, fatty fish, cod-liver oil, and (to a lesser extent) eggs. In the United States, milk is fortified with vitamin D2 (ergocalciferol, a plant steroid) or vitamin D3 and is the principal source of dietary vitamin D. In other parts of the world, cereals and bread products are often fortified with vitamin D.
The synthesis of vitamin D and its metabolism to 1,25(OH)2-vitamin D is closely coupled to calcium homeostasis, and is modulated by parathyroid hormone, serum calcium, and phosphorus levels [11]. When hypocalcemia occurs, serum PTH increases and enhances tubular reabsorption of calcium, as well as the activity of alpha-1-hydroxylase in the kidney [12]. This results in increased 1,25(OH)2-vitamin D production, in turn promoting intestinal calcium absorption [13]. PTH also stimulates bone osteoclast activity to mobilize bone calcium stores, thereby increasing serum calcium [14]. Estrogen, placental growth hormone, and prolactin may also regulate vitamin D metabolism, playing a role during pregnancy to meet increased calcium demands [15]. (See "Normal skeletal development and regulation of bone formation and resorption" and see "Metabolism of vitamin D").

DEFICIENCY AND RESISTANCE ? Vitamin D deficiency or resistance is caused by one of four mechanisms (see "Causes of vitamin D deficiency and resistance"):
* Impaired availability of vitamin D, secondary to inadequate dietary vitamin D, fat malabsorptive disorders, and/or lack of photoisomerization
* Impaired hydroxylation by the liver to produce 25-OH vitamin D
* Impaired kidney production of 1,25(OH)2-vitamin D
* End organ insensitivity to vitamin D metabolites (hereditary vitamin D resistant rickets).

Lack of vitamin D activity leads to reduced intestinal absorption of calcium and phosphorus. Early in hypovitaminosis D, hypophosphatemia is more marked than hypocalcemia. With persistent hypovitaminosis D, hypocalcemia causes a secondary hyperparathyroidism that leads to phosphaturia, demineralization of bones, and, without treatment, to osteomalacia in adults and rickets in children. (See "Clinical manifestations and etiology of osteomalacia" and see "Etiology and treatment of hypocalcemic rickets in children").
Glucocorticoids, when used chronically in high doses, inhibit the intestinal vitamin D dependent calcium absorption and therefore cause osteomalacia [12]. (See "Chapter 6F: Hormonal regulation of calcium and phosphate balance").
Subclinical vitamin D deficiency (or vitamin D insufficiency) is extremely common and may contribute to the development of osteoporosis. Vitamin D stores decline with age, especially in the winter. Controlled trials have demonstrated that vitamin D and calcium supplementation can reduce the risk of falls and fractures in the elderly. (See "Calcium and vitamin D supplementation in osteoporosis" and see "Treatment of vitamin D deficient states", section on Benefits of vitamin D repletion).

EXCESS ? In the 1940s and 1950s, a number of children developed hypercalcemia and some even had hypercalcemic-induced brain injury. This was felt to be a result of the high concentrations of vitamin D in fortified milk products [16]. Vitamin D supplementation in adults can result in intoxication, with manifestations which may include hypercalcemia, hypercalciuria, confusion, polyuria, polydipsia, anorexia, vomiting, muscle weakness, and bone demineralization with pain. Vitamin D intoxication may occur in fad dieters who consume "megadoses" of supplements or in patients on vitamin D replacement therapy for malabsorption, renal osteodystrophy, osteoporosis, or psoriasis. It has been documented in adults taking more that 60,000 international units per day [16].

The intake at which the dose of vitamin D becomes toxic is not clear. The Institute of Medicine has defined the "tolerable upper intake level" (UL) for vitamin D as 50 micrograms (2000 IU) daily for healthy adults and children 1 to 18 years. This is also the UL for pregnant and lactating women (show table 2) [17]. However, newer data indicate that higher doses may be safe, at least for a period of several months. Indications for high dose vitamin D supplementation and the UL for vitamin D supplementation are discussed in more detail separately. (See "Treatment of vitamin D deficient states", section on Dosing).

REQUIREMENTS ? Estimates of vitamin D requirements vary and depend in part on sun exposure and the standards used to define a deficient state. A minimum consumption of 200 IU (5 micrograms) daily of vitamin D per day is recommended by the National Research Council [18], and this is also the "adequate intake" estimated by the Institute of Medicine (show table 2) [17].
Due to increasing evidence of adverse health effects of subclinical vitamin D deficiency, vitamin D intakes above the "Adequate Intake" estimates are often recommended. For pregnant and lactating mothers with minimal sun exposure, intake of 10 micrograms (400 IU) often is recommended, and some studies suggest that considerably higher intakes may be necessary to maintain normal levels of 25OHD [19,20]. Intake of 20 micrograms (800 IU) of vitamin D daily often is recommended in older adults and appear to be necessary to minimize fracture risk [21-24]. (See "Calcium and vitamin D supplementation in osteoporosis", section on Optimal intake and see "Treatment of vitamin D deficient states").
Vitamin D supplementation should be given to infants who are exclusively breast fed because the vitamin D content of human milk is low. The Lawson Wilkins Pediatric Endocrine society recommends supplementation with 400 IU daily of vitamin D beginning within days of birth [25]. This represents a change from the 2003 AAP statement, in which intakes of 200 IU daily was considered adequate [26]. Most infant formulas contain at least 400 IU/L of vitamin D, so formula-fed infants will also require supplementation to meet this goal unless they consume at least 1000 mL daily of formula. (See "Introducing solid foods and vitamin and mineral supplementation during infancy", section on Vitamin D).
Vitamin D intake of at least than 400 IU/day also recommended for children who do not consume at least one liter of vitamin D fortified milk daily [25]. Casual exposure to sunlight provides amounts of vitamin D that are adequate to prevent rickets in many people, but is influenced by geographic location, season, use of sun block lotion, and skin pigmentation [13]. As an example, a Caucasian infant's vitamin D requirements are met by exposure to sunlight for 30 minutes per week, clothed only in a diaper, or two hours per week fully clothed with no hat [27]. African-American individuals require approximately 3-fold longer periods of sunlight exposure because of the protective pigmentation in their skin [28]. Currently recommended sun exposure for infants is insufficient to maintain vitamin D levels in the recommended range for dark-skinned infants and children, particularly at high latitudes and during the winter months [25].
Vitamin D requirements also may depend on disease states and concomitant medications. As an example, patients undergoing long-term treatment with steroids may benefit from higher levels of supplementation of vitamin D and calcium [29].
The best laboratory indicator of vitamin D adequacy is the serum 25-OH vitamin D concentration [17]. The lower limit of normal for 25OHD levels varies depending on the geographic location and sunlight exposure of the reference population (range 8 to 15 ng/ml). However, there is no consensus on the optimal 25OHD concentration for skeletal or extraskeletal health. Many agree that a minimum level of 30 ng/ml (75 nmol/L) is necessary. (See "Treatment of vitamin D deficient states", section on Biochemical criteria). The serum parathyroid hormone (PTH) level typically is inversely related to 25-OH vitamin D levels, and is a useful secondary indicator of vitamin D insufficiency.

SUMMARY AND RECOMMENDATIONS

* Very few foods contain vitamin D (fatty fish and eggs are the exception); dermal synthesis or fortified foods are the major sources of the vitamin. (See "Absorption and metabolism" above).
* Vitamin D3 (cholecalciferol) is synthesized nonenzymatically in skin from 7-dehydrocholesterol during exposure to the ultraviolet rays in sunlight. Cholecalciferol from the skin or diet must be hydroxylated in the liver, then kidneys to the active form of vitamin D, 1,25-dihydroxycholecalciferol (calcitriol) (show figure 1). (See "Absorption and metabolism" above).
* Vitamin D deficiency can be caused by unusually low sun exposure combined with lack of vitamin D fortified foods or malabsorption. Alternatively, impaired hydroxylation of vitamin D in liver or kidney can prevent metabolism into the physiologically active form. Rarely, genetic defects may cause the end organs to be unresponsive to vitamin D, as in hereditary hypophosphatemic rickets. (See "Deficiency and resistance" above, and see "Causes of vitamin D deficiency and resistance").
* A minimum consumption of 200 IU (5 micrograms) daily of vitamin D per day typically is recommended by US public health authorities. However, due to increasing evidence of adverse health effects of subclinical vitamin D deficiency, vitamin D intakes above the "Adequate Intake" estimates are often recommended, particularly in pregnancy and elderly individuals. In adults, 800 IU (20 micrograms) daily is often recommended for the prevention and treatment of osteoporosis (See "Requirements" above, and see "Calcium and vitamin D supplementation in osteoporosis").
* Excessive doses of vitamin D supplements in adults can result in intoxication, with symptoms including hypercalcemia, hypercalciuria, confusion, polyuria, polydipsia, anorexia, vomiting, muscle weakness, and bone demineralization with pain. In children, the hypercalcemia can cause brain injury. (See "Excess" above).
* The Institute of Medicine has defined the "tolerable upper intake level" (UL) for vitamin D as 50 micrograms (2000 IU) daily for healthy adults and children 1 to 18 years. Because of increasing evidence suggesting benefit from higher doses of vitamin D supplementation, some authorities recommend a higher upper intake level for adults. (See "Excess" above).

[niktak11]

"It (Vitamin D intoxication) has been documented in adults taking more that 60,000 international units per day."

I don't see anyone advising people to use this high a dose...

"The Institute of Medicine has defined the "tolerable upper intake level" (UL) for vitamin D as 50 micrograms (2000 IU) daily for healthy adults and children 1 to 18 years. Because of increasing evidence suggesting benefit from higher doses of vitamin D supplementation, some authorities recommend a higher upper intake level for adults. (See "Excess" above)."

Is this what you wanted us to see?

[GeneGnomeX]

I had to delete the introduction part of this paper to make it fit. Please read this and if you have evidence that shows that 5000 IU/day taken for more than 12 months is safe I would love to see it. So I suppose the challenge would now be to you Jack. I don't want to take up to much space so I won't post the other 2 articles unless I need to. But I think this illustrates why I gave the advice I gave, and supports it.

...

Many agree that a minimum level of 30 ng/ml (75 nmol/L) is necessary. (See "Treatment of vitamin D deficient states", section on Biochemical criteria).

Some research suggests higher doses (than 2000IU) are needed to maintain this blood concentration.

The Upper Limits are generally very conservative.

There seems to be a large individual variation, thus the emphasis of getting tested for 25-OHD concentrations. Bodyfat % will also influence D requirement, as it seems to be less available in obese persons.

[JacktheHero]

"The Institute of Medicine has defined the "tolerable upper intake level" (UL) for vitamin D as 50 micrograms (2000 IU) daily for healthy adults and children 1 to 18 years. Because of increasing evidence suggesting benefit from higher doses of vitamin D supplementation, some authorities recommend a higher upper intake level for adults. (See "Excess" above)."

Normally the IOM is known to give solid and safe advice. I think that's where Littleman's paper is from. I am sorry, you have been deceived by a purported American health "authority", Littleman.
I can tell you some facts about that paper.
The authors Sassan Pazirandeh and David L Burns did not even publish one peer reviewed study about vitamin D (at least I can't find any on pubmed). So let me now present some excerpts from vitamin D experts i.e. people devoting their career to study this topic, so they probably have a better grasp of the literature.
No one really knows why the IOM refuses to review the evidence.

If someone is authorative to speak on vitamin D, it must be Dr. Holick:
"It is known that lifeguards [that's a job, therefore a daily activity, therefore long term vitamin D levels] and sunbathers can have blood concentrations of 25(OH)D of 250 nmol/L (100 ng/mL), and they are not vitamin D intoxicated. Indeed, 25(OH)D concentrations of 325 nmol/L (150 ng/mL) with associated hypercalcemia are pathognomonic for hypervitaminosis D (vitamin D intoxication)" [1]

"Men and women in bathing suits who were exposed to a 1-MED dose of UVB radiation exhibited increases in blood concentrations of vitamin D that were equivalent to those observed with doses of 10 000-20 000 IU of vitamin D"
Sunbathing is not known to produce vitamin D toxicity, therefore a similar dose might be safe.

"Credible evidence of vitamin D toxicity in those chronically consuming 10,000 IU of supplemental cholecalciferol daily is absent in the literature." [2]

Dr. Vieth where the question originates from:
"To ensure that serum 25(OH)D concentrations exceed 100 nmol/L, a total vitamin D supply of 100 microg (4000 IU)/d is required. Except in those with conditions causing hypersensitivity, there is no evidence of adverse effects with serum 25(OH)D concentrations <140 nmol/L, which require a total vitamin D supply of 250 microg (10000 IU)/d to attain." [3]
From this we can easily deduce that some people will need chronic 4000-5000IU supplementation to achieve ~35ng/ml where the lowest mortality is at. Although, only blood levels will tell (most should need 2000-3000, sometimes even 0 IU with high sun exposure).

From a review by Armin Zittermann:
"Circulating 25(OH)D levels between 100 and 200 nmol/l [some people need up to 10,000 IU to achieve those levels as Vieth and others repeatedly point out] can be regarded as adequate concentrations, where no disturbances in vitamin D-dependent body functions occur (Peacock, 1995). A rationale for this assumption is the observation that subjects with a constantly high u.v. B exposure living close to the equator have mean 25(OH)D levels of 107 nmol/l and upper serum levels (+2 SD) of 163 nmol/l [that's a lot! Resulting in no signs of toxicity, but lower cancer rates if adjusted for confounders] throughout the year (Linhares et al. 1984)." [4]

Then there's the empirical evidence, Dr. Cannell and Dr. Davis (a cardiologist) regularly supplement with up to 20,000 IU for prolonged periods of time e.g. in the obese. Oh, and the Imminst community, where dozens of people have been supplementing with 5,000 IU and upwards. Oh, oh and CRONies even supplement with 2000 IU upwards (however, their bodyweight is probably half of yours!), so does Michael Rae one of the top researchers into life extension, who is cautious as hell, again at a bodyweight of ~100 pounds.

Either way, deficiency is probably more dangerous than a highish (non-toxic) dose, as shown by the epidemiologic study I referenced earlier. Only blood levels can tell you if you are in the optimal range.

Littleman: "I am very hesitant about giving people advice over message boards b/c the things we say on here some people will take as advice from a physician without ever looking into themselves."
I am not, if giving possibly dangerous advice I mention a disclaimer ("Please contact your doctor, before..."), but 2000 IU as a starting dose for bodybuilders with lowish sun exposure is as safe and conservative as it gets.
Ok, maybe one should mention certain diseases, which make people sensitive to vitamin D, so let's do it now: sarcoidosis, non-hodgkins lymphoma and oat-cell carcinoma IIRC. So, guys, go see your doctor, but try to find a doctor who at least has read Dr. Holick's papers....

Conclusion:
So I've provided 4 (I've only read 3 of them, though) reviews by authorative vitamin D experts, regularly publishing vitamin D research in renown peer-reviewed journals. They cite explicit examples and all arrive at the same conclusion, that the literature cannot credibly support toxicity of 10,000 IU vitamin D. I've also given several examples of strong empirical evidence in favour of highish supplementation. The only possible conclusion is that people have been deceived by the IOM and other authorities...
All my advice is based on the lower range of intakes suggested by the top vitamin D researchers - I suppose that's as safe as it gets. Actually my advice may be dangerous, not because I recommend too much, but because I may recommed too little supplementation.

[1] Am J Clin Nutr 2004;80(suppl):1678S– 88S.
Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease.
[2] Altern Med Rev. 2008 Mar;13(1):6-20.
Use of vitamin D in clinical practice.
Cannell JJ, Hollis BW.
[3]Am J Clin Nutr. 1999 May;69(5):842-56.
Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Vieth R.
[4] British Journal of Nutrition (2003), 89, 552–572
Vitamin D in preventive medicine: are we ignoring the evidence?
Armin Zittermann.

[ss4vegeta1]

Yeah I think we are all lacking when it comes to good old D3. The thing that people don't know is that everything is fortified with synthetic vitamins. D3 is much better on the body. I took 5,000IUs for a month and nothing happened to me. I may double that this year.

[Dutchman]

Somehow I missed this thread when my hard drive went down. I am all in Jack's corner on this one. My wife and I, (she is on Oxy 24/7, has Atrial Fib and a killer skin disease called Von Recklingshausen) wheras I am healthy as a horse. We attribute her relative good health, still 5 years after the docs told her 'to get her things in order" to a combo of supps first of all Vitamin D3 of which we each take 5,000 IU ED for well over a year now. We live north of Orlando and get tons of sun with her daily 1 hour walks in the pool (the only place she can exercise and breathe without her Oxy). We have discussed her supp regimine and gotten the approval from her GP, Pulmonologist and Cardiologist. FYI they also approved her high dose Omega 3 and Ubiquinol (CoQ10) levels. My niece who has MS has been investigating a Govt program where they are testing out some 30,000 IUs ED. We aim at getting to 70 nmol levels but actually have not hit it. Some of our problem may be age related as our production goes down.

[rocco555]

My personal results

Before any D3 sup
Vit D 25-OH 29 (30-100)
Testosterone 520 (290-950)

After 2 months 5k IU/Day
Vit D 25-OH 45 (30-100)
Testosterone 574 (290-950)

After another 2 months 7.5k IU/Day
Vit D 25-OH 54 (30-100)
Testosterone 587 (290-950)

No or very low sun exposure during the whole test

Hope this helps

[tadpole25]

Depends on sunlight absorption.

I was taking 1000 IU a day for a month before I had my blood drawn. The test results came out that I was STILL deficient of Vitamin D.

So now I take 5800 IU.

[vanslix]

As bodyweight evidently seems to play a role in vitamin D toxicity, big guys, e.g. bodybuilders, should have even less of a problem with a dose of 2000 IU and up.

As it's a fat soluble vitamin, I'm not sure how LBM would alter dosing.

[Robosco]

Damn, I just bought a bottle of 5,000iu caps. After reading this thread, 5,000iu a day might be too much. I get about 15 minutes of strong sunshine a day. Do you guys think I should take this every other day instead? It's fat soluble, it sticks with you for a while doesn't it?

[PinchTheBear]

Damn, I just bought a bottle of 5,000iu caps. After reading this thread, 5,000iu a day might be too much.

That's not even remotely too much. Thread is tldr but the current RDA is way too low and always was. Unfortunately even recent texts are further dogmatizing a low RDA/tolerable dose based on when we only really appreciated its role in calcium absorption, before we understood it as a transcription factor.

[chromaffin]

That's not even remotely too much. Thread is tldr but the current RDA is way too low and always was. Unfortunately even recent texts are further dogmatizing a low RDA/tolerable dose based on when we only really appreciated its role in calcium absorption, before we understood it as a transcription factor.

Indeed.