The following (2009? 2010?) has just a few hyperlinks of the original great article by Kerri Knox

Yes, you CAN Overdose on Vitamin D, but the risk of too LITTLE is more than your risk of getting too much Vitamin D!

Doctors seem to have a fear of recommending ANY amount Vitamin D for fear of causing Vitamin D toxicity.
But while Vitamin D Toxicity IS a reality, it is a rare phenomenon to have a Vitamin D toxicity. Interestingly, it seems like EVERYONE is always concerned about taking excess Vitamin D- while almost no one is aware of or even slightly concerned about an:
Overdose on Selenium or Overdose on Magnesium

However, selenium toxicity is MUCH more common that Overdose on Vitamin D. And while Selenium Overdose can occur in nature- an overdose on Vitamin D NEVER occurs with naturally occurring vitamin d in Vitamin D Foods or Vitamin D From Sunlight.

Who is at risk to overdose on Vitamin D?
Anyone who takes Vitamin D supplements CAN take too much Vitamin D. But the majority of documented overdose on vitamin d are from:

• Children whose parents accidentally give them massive doses of vitamin d
• Elderly people incorrectly taking massive vitamin d dosages
• Adults who take more than 10,000 IU's per day for long periods of time. {over a year}
• 'Industrial Accidents' where massive quantities of vitamin d are put into fortified foods in error

These categories comprise nearly all people who have had an Overdose on Vitamin D.

Tolerable Upper Limit of Vitamin D

Most governments have set a 'Tolerable Upper Limit' also called a 'safe upper limit' dosage for vitamin d supplements.
This is a dosage in which healthy people can take for extended periods of time with few to no vitamin d overdose symptoms.

Currently, the Tolerable Upper Limit is Vitamin D 2000 IU per day. Vitamin D research shows that this 'upper limit' of Vitamin D 2000 IU per day SHOULD be the Recommended Daily Allowance for vitamin d therapy - NOT the Tolerable Upper Limit. And this dosage is certainly not anywhere near getting excess Vitamin D.

The researchers state that the tolerable upper limit of 2000 IU's is a great daily dose for vitamin d therapy for children, but that it has no basis in any science for an upper level for adults and is not in any way excess vitamin d since the levels required for Symptoms of Vitamin D overdose are at least 5 times that much

In fact, Vitamin D Scientists have come together with this 'Call to Action' letter to induce the North American governments to make the use of Vitamin D 2000 IU as the baseline minimum requirement for all healthy adults.

"The conclusion was that the UL (safe upper limit) for vitamin D consumption by adults should be 10,000 IU/d.
This indicates that the margin of safety for vitamin D consumption for adults is (more than) 10 times any current recommended intakes."
-Vieth et al, 'The urgent need to recommend an intake of vitamin D that is effective'

Other studies agree that current guidelines are not based in fact. The Research Article The Pharmacology of Vitamin D, Including Fortification Strategies states that there is "no evidence of adverse effects from taking 10,000 IU of Vitamin D a day".

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."

In another study entitled, 'Vitamin D toxicity, policy, and science' the author states,

"a prolonged intake of 250 mug (10,000 IU)/d of vitamin D(3) is likely to pose no risk of adverse effects in almost all individuals in the general population; this meets the criteria for a tolerable upper intake level."

What are the Vitamin D overdose Symptoms

Be SURE that you understand that feeling bad after you take vitamin d is almost surely NOT an overdose, but simply Vitamin D Side Effects. They are NOT the same thing although they are VERY often confused. Please read the page on Vitamin D Side Effects if you feel bad after taking vitamin d because there are ways that you can resolve that.

But if you have been taking MASSIVE doses of vitamin d, then the Vitamin D overdose symptoms that might make you seek medical attention if you are taking large amounts of Vitamin D Supplements are:

• abdominal cramps
• nausea
• frequent urination
• weakness

The presence of a High Vitamin D Level WITH anElevated Calcium in the blood is really the only useful test for overdose on Vitamin D as there is a wide variation in how people tolerate upper level limits of the Vitamin D blood test. If you have high calcium levels already, that is one of the few Vitamin D Contraindications and you must NOT take vitamin d supplements unless you are specifically told to by your doctor.

How Much Does it Take to Overdose on Vitamin D

While high Blood Calcium Levels are useful to determine an overdose on vitamin d, it really takes an AMAZINGLY large amount to cause a Vitamin D Overdose. In fact, in East Germany between the 1940's and 1960's, children would ROUTINELY get 6 doses of 600,000 IU's of Vitamin D between birth and 18 months old.

This gave these small children an incredible 3,600,000 IU's of Vitamin D in 18 months. That is Three Million Six Hundred Thousand IU's in 18 months in small children as a ROUTINE hospital procedure for several decades!!

A study called Intermittent High Dose Vitamin D During Infancy questioning this practice's safety noted that, while many of the children developed transient high levels of blood calcium levels, "...all the infants appeared healthy and repeated inquiries... have failed to identify clinical vitamin d toxicity as a result of the prophylactic program...".

Also, it is a common practice for doctors around the world to use a therapy for rickets in infants and children a Vitamin D Therapy called 'Stosstherapy' which gives these children with rickets a one-time Vitamin D Injection of 600,000 IU's.

Again, Vitamin D toxicity and Vitamin D overdose symptoms are Extremely rare- so in the vast majority of cases, if you are taking Vitamin D Supplements, even accidentally taking a full bottle all at once will not cause an Overdose on Vitamin D. However, since a Vitamin D Overdose CAN occur, always stick with recommended dosages and Get your Vitamin D Level Checked in order to get your levels up to the 'optimal' Vitamin D Level as recommended by the latest research on vitamin d toxicity and vitamin d therapy.

Can you get Vitamin D Toxicity from the sun?

There have been zero reported incidences of Vitamin D Toxicity from too much sunshine.

The body seems to have a feedback mechanism that prevents too much Vitamin D from being made through the skin even though one exposure can give you the equivalent of up to 20,000 IU's for one single whole body exposure!
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See also Vitamin D Life

• Overview Toxicity of vitamin D
• All items in category Toxicity and Vitamin D 96 items
• All items in category Megadose/Loading Dose and Vitamin D 154 items
• The 2,000 IU toxicity scare got started in the 1950’s,
  Was proven wrong in the 1960’s and has persisted now for over 50 years.