Hypervitaminosis D

Encyclopedia : H : HY : HYP : Hypervitaminosis D

In terms of the likelihood of poisoning, Vitamin D seems to be one of the least poisonous substances known. Overdose occurs at more than 100 times the daily RDA (more or less a bottle of vitamin D tablets per day), for several months. Acute one-time overdose requires over 50mg (ten thousand times the RDA). Foods contain low levels, and have not been known to cause overdose.

Although taking excessive amounts of cod liver oil over months or years could produce an overdose in theory, it is almost always associated with forms of vitamin D that require a doctor's prescription. Overdose has also occurred due to industrial accidents, for example when incorrectly formulated pills were sold or missing industrial concentrate cans misused as cans of milk.

Symptoms of vitamin D poisoning include:

Dehydration
Vomiting
Decreased appetite (anorexia)
Irritability
Constipation
Fatigue

An excess of vitamin D causes abnormally high blood concentrations of calcium (hypercalcemia) which can eventually cause severe damage to the bones, soft tissues, and kidneys. It can also damage the kidney and produce kidney stones. Ongoing research indicates antagonism with oil soluble menatetrenone, MK-4, an internally transported natural form of vitamin K_{2_{, which is associated with bone formation and calcium retention in the bones.

Note: Hypervitaminosis D symptoms appear several months after excessive doses of vitamin D are administered, by which time the condition is usually very serious.

Comparative safety statistics
Deaths by vitamin poisoning appear to be quite rare in the US, typically none in a given year. However several deaths per year are typically associated with iron-containing supplements, especially brightly-colored, sugar-coated, high-potency iron supplements. This compares with 59 deaths due to aspirin poisoning in [2003], 147 deaths associated with acetaminophen-containing products in [2003], and an average of 54 deaths per year due to lightning for [1990-2003].

See also
Vitamin poisoning
External links
[Hypervitaminosis D Medical Information]

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