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Hypervitaminosis is a condition of abnormally high storage levels of
vitamin Vitamins are Organic compound, organic molecules (or a set of closely related molecules called vitamer, vitamers) that are essential to an organism in small quantities for proper metabolism, metabolic function. Nutrient#Essential nutrients, ...
s, which can lead to various symptoms as over excitement, irritability, or even
toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...
. Specific medical names of the different conditions are derived from the given vitamin involved: an excess of
vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...
, for example, is called hypervitaminosis A. Hypervitaminoses are primarily caused by fat-soluble vitamins ( D and A), as these are stored by the body for longer than the water-soluble vitamins. Generally, toxic levels of vitamins stem from high supplement intake and not always from natural sources but rather the mix of natural, derived vitamins and enhancers (vitamin boosters). Toxicities of fat-soluble vitamins can also be caused by a large intake of highly fortified foods, but natural food in modest levels rarely deliver extreme or dangerous levels of fat-soluble vitamins. The Dietary Reference Intake recommendations from the
United States Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...
define a "tolerable upper intake level" for most vitamins. For those who are entirely healthy and do not experience long periods of avitaminosis, vitamin overdose can be avoided by not taking more than the normal or recommended amount of multi-vitamin supplement shown on the bottle and not ingesting multiple vitamin-containing supplements concurrently.


Signs and symptoms

A few described symptoms: * Frequent urination or cloudy urine * Increased urine amount * Eye irritation and/or increased sensitivity to light * Irregular and/or rapid heartbeat * Bone and joint pain (associated with avitaminosis) * Muscle pain * Confusion and mood changes (e.g. irritability, inability to focus) * Convulsions * Fatigue * Headache * Flushing of skin (associated with niacin (vitamin B3) overdose) * Skin disturbances (e.g. dryness, itching, cracking of skin, rashes, increased sensitivity to sun) * Changes of hair texture (e.g. thickening and/or clumping of hair) * Appetite loss * Constipation (associated with iron or calcium overdose) * Nausea and vomiting * Diarrhoea * Moderate weight loss (more commonly seen in long-term overdose cases)


Causes

With few exceptions, like some vitamins from B-complex, hypervitaminosis usually occurs with the fat-soluble vitamins A and D, which are stored, respectively, in the liver and fatty tissues of the body. These vitamins build up and remain for a longer time in the body than water-soluble vitamins. Conditions include: * Hypervitaminosis A * Hypervitaminosis D * Vitamin B3 ยง Toxicity * Megavitamin-B6 syndrome *
Vitamin E Vitamin E is a group of eight compounds related in molecular structure that includes four tocopherols and four tocotrienols. The tocopherols function as fat-soluble antioxidants which may help protect cell membranes from reactive oxygen speci ...
toxicity


Prevention

Prevention in healthy individuals not having any periods of avitaminosis or vitamin (vegetables) lack for 2 years at least is by not taking more than the expected normal or recommended amount of vitamin supplements.


Epidemiology

In the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, overdose exposure to all formulations of "vitamins" (which includes multi-vitamin/mineral products) was reported by 62,562 individuals in 2004 with nearly 80% of these exposures in children under the age of 6, leading to 53 "major" life-threatening outcomes and 3 deaths (2 from vitamins D and E; 1 from a
multivitamin A multivitamin is a preparation intended to serve as a dietary supplement with vitamins, dietary minerals, and other nutritional elements. Such preparations are available in the form of tablets, capsules, pastilles, powders, liquids, gummies, o ...
with iron). This may be compared to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004). In 2016, overdose exposure to all formulations of vitamins and multi-vitamin/mineral formulations was reported by 63,931 individuals to the
American Association of Poison Control Centers America's Poison Centers (formerly known as American Association of Poison Control Centers - AAPCC) is a national nonprofit organization founded in 1958 that represents the United States of America, nation's 53 Poison control center, poison cente ...
with 72% of these exposures in children under the age of five. No deaths were reported.


See also

*
Avitaminosis Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a ''primary deficiency'', whereas when due to an underlying disorder such as malabsorption it is called a ''seconda ...
*
Megavitamin therapy Megavitamin therapy is the use of large doses of vitamins, often many times greater than the recommended dietary allowance (RDA) in the attempt to prevent or treat diseases. Megavitamin therapy is typically used in alternative medicine by pract ...
*
Vitamin C megadosage Vitamin C megadosage is a term describing the consumption or injection of vitamin C (ascorbic acid) in doses well beyond the current United States Recommended Dietary Allowance of 90 milligrams per day, and often well beyond the tolerable u ...


References


External links


Dietary reference intakes
official website. {{DEFAULTSORT:Vitamin Poisoning Effects of external causes