Are Vitamin D pills toxic for humans in the long term?

Question

Vitamin D (Calciferol) is frequently used in rat poison and very toxic when consumed by cats and dogs: Pet Poison Helpline

This is one of the most dangerous mouse and rat poisons on the market and unfortunately, seems to be gaining in popularity. Cholecalciferol, or activated vitamin D3, causes a life-threateningly high calcium and phosphorus level in the body, resulting in severe, acute kidney failure. This can progress to chronic kidney failure and have long-term repercussions.

Vitamin D seems to be beneficial if consumed by humans according to some sources: Wikipedia

Shane Ellison, who calls himself "The People's Chemist", says Vitamin D toxicity builds up in the body and will eventually kill a human the same way a rat is killed when consuming it:

Nutritionists are unaware. Male cheerleader turned nutrition guru, Johnny Bowden (Whoops, I spelled his name wrong.), proves it. Vitamin D pills are his crown jewels, and he likes “bromancing the Dr. Cannell stone.” He often uses statistical contortionism to push it as a non-toxic cure-all, akin to water! He doesn’t understand that, unlike water, it’ s a “cumulative poison;” meaning that it’s absorbed by fat cells and festers internally for months. It’s called bio-accumulation. And that’s where small, daily ingestion becomes dangerous, the repeated use over time gives way to side effects – death in slow motion. Water on the other hand gets passed through readily after used, and doesn’t snuggle into the far away corners of our fat cells.

Another article by him

The “rickets rationale” for supporting the use of synthetic vitamin D is the most frustrating. It purports that “vitamin D” cured the paralyzing disease, which is prima facie evidence of its healing qualities. Not true. The plethora of “sunshine hormones” produced by the skin, and those found naturally in cod liver oil, cured rickets, not vitamin D pills made in the stinky labs of Big Pharma. Purveyors of this myth have the Big Pharma marketing noose firmly around their neck, and probably don’t even know it.

If the rickets rationale didn’t win you over, the “cancer cure con” probably did. You’ve seen it plastered on the headlines of every paper in the U.S and even on well known, natural health websites: Vitamin D fights cancer. The redundancy itself should be your first clue that “something fishy” is going on. The anti-cancer statements come direct from short term trials performed by “advisors” to Big Pharma and published in the top nutrition journals! Worse, the trials only show a small statistical association of low cancer rates among vitamin D users over about a 5 year period. This is plain silly.

Cancer takes more than 5 years to develop. Even heavy smokers can survive 5 years without a cancer diagnosis, but we know cigarettes are a real threat. Thus, any study on cancer lasting five years has very little value. This same scheme was used by the cigarette industry to erroneously thwart off the cancer claims in the early 1970’s. Now it’s being used to pretend vitamin D staves off cancer. It’s a con, and long term vitamin D studies (which are being ignored) show just the opposite (just like they did with cigarettes, of course). In conclusion, I’m sounding the alarm that a slow vitamin D poisoning is happening worldwide. Vitamin D supplements and fortified foods are attacking the body from numerous sources, where it’s behaving like the rat poison it is. You choose, sunshine or vitamin D pills (D2, D3 or otherwise)?

Wikipedia on supplementation:

Supplements The effects of vitamin D supplementation on health are uncertain.[10] A United States Institute of Medicine, (IOM) report states: "Outcomes related to cancer, cardiovascular disease and hypertension, diabetes and metabolic syndrome, falls and physical performance, immune functioning and autoimmune disorders, infections, neuropsychological functioning, and preeclampsia could not be linked reliably with calcium or vitamin D intake and were often conflicting."[11]:5 Some researchers claim the IOM was too definitive in its recommendations and made a mathematical mistake when calculating the blood level of vitamin D associated with bone health.[97] Members of the IOM panel maintain that they used a "standard procedure for dietary recommendations" and that the report is solidly based on the data. Research on vitamin D supplements, including large scale clinical trials, is continuing Maxmen A (2011). "Nutrition advice: the vitamin D-lemma". Nature 475 (7354): 23–5. doi:10.1038/475023a. PMID 21734684.

So are vitamin D pills safe in the long run?

Answer 1

It is possible to take daily vitamin D supplementation and avoid possible adverse effects if you keep your dosage below the Tolerable Upper Intake Level.

This level has been published by Health Canada as follows:

Age group             Recommended Dietary Allowance  Tolerable Upper Intake Level (UL)
0-6 months            400 IU  (10 mcg)           1000 IU (25 mcg)
7-12 months           400 IU  (10 mcg)           1500 IU (38 mcg)
1-3 years             600 IU (15 mcg)            2500 IU (63 mcg)
4-8 years             600 IU (15 mcg)            3000 IU (75 mcg)
9-70 years            600 IU (15 mcg)            4000 IU (100 mcg)
Adults > 70 years     800 IU (20 mcg)            4000 IU (100 mcg)
Pregnancy & Lactation 600 IU (15 mcg)            4000 IU (100 mcg)

They say:

The IOM expert committee reviewed a number of health outcomes that could potentially be related to calcium and vitamin D, such as cancer, cardiovascular disease, diabetes, and immunity, and found that the evidence existing to date is inconsistent and does not demonstrate a cause-and-effect relationship. Consequently, these health outcomes could not be used for the purposes of determining nutrient requirements.

The evidence surrounding the role of calcium and vitamin D in bone health was judged to be convincing, and was used as the basis for determining requirements for calcium and vitamin D.

From a review article on Vitamin D:

Vitamin D intoxication is extremely rare but can be caused by inadvertent or intentional ingestion of excessively high doses. Doses of more than 50,000 IU per day raise levels of 25-hydroxyvitamin D to more than 150 ng per milliliter (374 nmol per liter) and are associated with hypercalcemia and hyperphosphatemia.

Doses of 10,000 IU of vitamin D3 per day for up to 5 months, however, do not cause toxicity. (Holick, 2007)

He concludes:

Much evidence suggests that the recommended adequate intakes are actually inadequate and need to be increased to at least 800 IU of vitamin D3 per day. Unless a person eats oily fish frequently, it is very difficult to obtain that much vitamin D3 on a daily basis from dietary sources. Excessive exposure to sunlight, especially sunlight that causes sunburn, will increase the risk of skin cancer. Thus, sensible sun exposure (or ultraviolet B irradiation) and the use of supplements are needed to fulfill the body's vitamin D requirement. (Holick, 2007)

Another study says:

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 mg (10000 IU)/d to attain. (Vieth, 1999)

Published cases of vitamin D toxicity with hypercalcemia, for which the 25(OH)D concentration and vitamin D dose are known, all involve intake of ≥1000 mg (40000 IU)/day. (Vieth, 1999)

Epidemiologic studies show that higher serum 25(OH)D concentrations or environmental ultraviolet light exposure are associated with lower rates of breast, ovarian, prostate, and colorectal cancers. (Vieth, 1999)

For example, one of the studies found that:

[I]mproving vitamin D nutritional status substantially reduced all-cancer risk in postmenopausal women. (Lappe, 2007)

As stated above, Health Canada did not believe that there is yet enough evidence to deem this a cause-and-effect relationship.

References

Michael F. Holick, M.D., Ph.D., Vitamin D Deficiency, N Engl J Med 2007; 357:266-281, July 19, 2007, DOI: 10.1056/NEJMra070553

Joan M Lappe, Dianne Travers-Gustafson, K Michael Davies, Robert R Recker, and Robert P Heaney, Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial, Am J Clin Nutr June 2007 vol. 85 no. 6 1586-1591

Reinhold Vieth, Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety, Am J Clin Nutr 1999;69:842–56.