Hypervitaminosis D is a state of vitamin D Vitamin D is a group of fat-soluble secosteroids, the two major physiologically relevant forms of which are vitamin D2 and vitamin D3 (cholecalciferol). Vitamin D without a subscript refers to either D2 or D3 or both. Vitamin D3 is produced in the skin of vertebrates after exposure to ultraviolet B light from the sun or artificial sources, and toxicity.
The recommended daily allowance Reference Daily Intake (RDI) is the daily dietary intake level of a nutrient which was considered (at the time they were defined) to be sufficient to meet the requirements of nearly all (97–98%) healthy individuals in each life-stage and sex group. The RDI is used to determine the Daily Value which is printed on food labels in the U.S., Canada, is 400 IU per day. Overdose has been observed at 1925 µg/d (77,000 IU per day). Acute overdose requires between 15,000 µg/d (600,000 IU per day) and 42,000 µg/d (1,680,000 IU per day) over a period of several days to months, with a safe intake level being 250 µg/d (10,000 IU per day).[1] Foods contain low levels, and have not been known to cause overdose.
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Symptoms and presentation
Symptoms of vitamin D poisoning include:
- Dehydration Dehydration is defined as an excessive loss of body fluid. It is literally the removal of water (Ancient Greek: ὕδωρ hýdōr) from an object, however in physiological terms, it entails a deficiency of fluid within an organism
- Vomiting Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure. The feeling that one is about to vomit is called nausea, which usually precedes, but does not always lead to,
- Decreased appetite The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is termed anorexia, while polyphagia is increased eating (anorexia Anorexia (deriving from the Greek "α-" (a(n)-, a prefix that denotes absence) + "όρεξη" (orexe) = appetite) is the decreased sensation of appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a decreased appetite, some of which may be)
- Irritability Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration
- Constipation Constipation refers to bowel movements that are infrequent and hard to pass. Constipation is a common cause of painful defecation. Severe constipation includes obstipation and fecal impaction (see also Bowel obstruction)
- Fatigue Fatigue is a state of awareness. It can describe a range of afflictions, varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles. It can be both physical and mental. Physical fatigue is the inability to continue functioning at the level of one's normal abilities. It is ubiquitous in everyday life,
An excess of vitamin D causes abnormally high blood Blood is a specialized bodily fluid that delivers necessary substances to the body's cells – such as nutrients and oxygen – and transports waste products away from those same cells concentrations of calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, (hypercalcemia Hypercalcemia is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased), which can cause overcalcification of the bones Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue. Because bones come in a variety of shapes and have a complex internal and external structure, soft tissues In medicine, the term soft tissue refers to tissues that connect, support, or surround other structures and organs of the body, not being bone, heart The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions. The term cardiac (as in cardiology) means "related to the heart" and comes from the Greek καρδιά, kardia, for "heart" and kidneys The kidneys are paired organs with several functions. They are seen in many types of animals, including vertebrates and some invertebrates. They are an essential part of the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid-base balance, and regulation of blood pressure. They serve the. It can also damage the kidney and produce kidney stones Kidney stones result from stones or renal calculi (from Latin ren, renes, "kidney" and calculi, "pebbles") in the ureter. The stones are solid concretions or calculi (crystal aggregations) formed in the kidneys from dissolved urinary minerals. Nephrolithiasis (from Greek νεφρός (nephros, "kidney") and λιθoς (. In addition, hypertension Hypertension or high blood pressure is a chronic medical condition in which the systemic arterial blood pressure is elevated. It is the opposite of hypotension. It is classified as either primary (essential) or secondary. About 90–95% of cases are termed "primary hypertension", which refers to high blood pressure for which no medical can result. Ongoing research indicates antagonism with oil soluble menatetrenone Menatetrenone is a menaquinone compound used as a hemostatic agent and as adjunctive therapy for the pain of osteoporosis. It is marketed for the latter indication in Japan by Eisai Co., under the trade name Glakay, MK-4, an internally transported natural form of vitamin K2, 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. In almost every case, a low calcium diet combined with corticosteroid drugs will allow for a full recovery within a month.
Long term effects of supplementary oral intake
Vitamin D toxicity is unlikely except when certain medical conditions are present, such as primary hyperparathyroidism Primary hyperparathyroidism causes hypercalcemia through the excessive secretion of parathyroid hormone (PTH), usually by an adenoma (benign tumors) of the parathyroid glands. Its incidence is approximately 42 per 100,000 people. It is almost exactly three times as common in women as men, sarcoidosis Sarcoidosis , also called sarcoid or Besnier-Boeck disease, is a disease in which abnormal collections of inflammatory cells (granulomas) form as nodules in many organs of the body. Its cause is unknown. Granulomas most often appear in the lungs or the lymph nodes, but virtually any organ can be affected. Normally the onset is gradual. Sarcoidosis, tuberculosis Tuberculosis or TB is a common and often deadly infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis in humans. Tuberculosis usually attacks the lungs but can also affect other parts of the body. It is spread through the air, when people who have the disease cough, sneeze, or spit. Most infections in, and lymphoma Lymphoma is a cancer that begins in the lymphatic cells of the immune system and presents as a solid tumor of lymphoid cells. It is treatable with chemotherapy, and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage of the disease. These malignant cells often originate in.[2][3] This is because within about 20 minutes of ultraviolet exposure in light skinned individuals (3–6 times longer for pigmented skin) the concentration of vitamin D precursors produced in the skin reach an equilibrium In a chemical process, chemical equilibrium is the state in which the chemical activities or concentrations of the reactants and products have no net change over time. Usually, this would be the state that results when the forward chemical process proceeds at the same rate as their reverse reaction. The reaction rates of the forward and reverse, and any further vitamin D that is produced is degraded.[4] According to some sources, endogenous production with full body exposure to sunlight is approximately 250 µg (10,000 IU) per day.[5] According to Holick, "the skin has a large capacity to produce cholecalciferol"; his experiments indicate that,
"[W]hole-body exposure to one minimal erythemal dose of simulated solar ultraviolet radiation is comparable with taking an oral dose of between 250 and 625 micrograms (10 000 and 25 000 IU) vitamin D."[4]
It is on the basis of the supposedly similar effect of supplementation and whole body exposure to one erythemal dose that a leading researcher [6] has suggested that 250 micrograms/day (10,000 IU) in healthy adults should be adopted as the tolerable upper limit.[6] Supplements and skin synthesis have a different effect on on serum 25(OH)D concentrations;[7] endogenously synthesized vitamin D3 travels in plasma almost exclusively on vitamin D-binding protein (VDBP), providing for a slower hepatic delivery of the vitamin D and the more sustained increase in plasma 25-hydroxycholecalciferol observed after depot, parenteral administration of vitamin D. Yet the orally administered route vitamin D produces swift hepatic delivery of vitamin D, and transient, but nonetheless abrupt, increases in plasma 25-hydroxycholecalciferol. The richest food source of vitamin D — wild salmon — would require 35 ounces a day to provide 10,000IU.[8] It has been argued[9] that ingestion of vitamin D in large amounts was achieved in the process of grooming by furry human ancestors and that from UV-exposed human skin secretions early humans ingested vitamin D by licking the skin, however this putative ingestion of vitamin D by early humans is not quantified. A study[10] found 34% of its sample of healthy western Canadians to be under 40nmol/L at some point and 97% to be under 80nmol/L at least once. It has been questioned.[11] whether to ascribe a state of sub-optimal vitamin D status when the annual variation in ultraviolet Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 10 nm to 400 nm, and energies from 3eV to 124 eV. It is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet will naturally produce a period of falling levels, and such a seasonal decline has been a part of Europeans' adaptive environment[12] for 1000 generations,[13] is clear thinking. Still more contentious is recommending supplementation when those supposedly in need of it are labeled healthy and serious doubts exist as to the long term effect of attaining and maintaining serum 25(OH)D of at least 80nmol/L by supplementation.[11]
Cardiovascular disease
There is a certain amount of evidence to suggest that dietary vitamin D may be carried by lipoprotein particles[14] into cells of the artery wall and atherosclerotic plaque, where it may be converted to active form by monocyte-macrophages.[15] These findings raise questions regarding the effects of vitamin D intake on atherosclerotic calcification and cardiovascular risk. Dietary vitamin D may be causing vascular[16] calcification Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcifediol Calcifediol , also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D (abbreviated 25(OH)D), is a prehormone which is produced by hydroxylation of vitamin D3 (cholecalciferol) in the liver. Calcidiol is then converted in the kidneys (by the enzyme 25(OH)D-1α-hydroxylase) into calcitriol (1,25-(OH)2D3), a secosteroid hormone (25-hydroxy-vitamin D) is implicated in the etiology of atherosclerosis, especially in non-Caucasians.[17][18][19] Vitamin D levels are generally higher in the physically fit but are lower in those of tropical origin, this is a confound for any attempt to make a worldwide recommendation for vitamin D.[20] 1,25-Dihydroxycholecalciferol Calcitriol (pronounced /ˌkælsɨˈtraɪ.ɒl/ or English pronunciation: /kælˈsɪtri.ɒl/), also called 1,25-dihydroxycholecalciferol or 1,25-dihydroxyvitamin D3, is the hormonally active form of vitamin D with three hydroxyl groups (abbreviated 1,25-(OH)2D3 or simply 1,25(OH)2D). It increases the level of calcium (Ca2+) in the blood by (1)(active serum vitamin D) levels are inversely correlated with coronary calcification[21] moreover one-alpha-hydroxy-cholecalciferol, an active vitamin D analog[22] therapy seems to protect patients from developing vascular calcification.[23] African Americans have higher active serum vitamin D levels.[24][25][26] There are racial differences in the association of coronary calcified plaque[27] in that there is less calcified atherosclerotic plaque in the coronary arteries of African-Americans than in whites. One study found an elevated risk of ischaemic heart disease Ischaemic or ischemic heart disease , or myocardial ischaemia, is a disease characterized by ischaemia (reduced blood supply) to the heart muscle, usually due to coronary artery disease (atherosclerosis of the coronary arteries). Its risk increases with age, smoking, hypercholesterolaemia (high cholesterol levels), diabetes, hypertension (high in Southern India in individuals whose vitamin D levels were above 89 ng/mL.[18] Freedman et al. (2010) have found that serum vitamin D correlates in African Americans, but not in Euro-Americans, with calcified atheroscleratic plaque. Pharmacokinetics of vitamin D toxicity states - "Early assumptions that 1,25(OH)2D3 might cause hypercalcemia in vitamin D toxicity have been replaced by the theories that 25(OH)D3 at pharmacologic concentrations can overcome vitamin D receptor affinity disadvantages to directly stimulate transcription or that total vitamin D metabolite concentrations displace 1,25(OH)2D from vitamin D binding".[28] Freedman et al. (2010) states - "Higher levels of 25-hydroxyvitamin D seem to be positively correlated with aorta and carotid CP in African Americans but not with coronary CP. These results contradict what is observed in individuals of European descent".[29] Recommendations stemming for a single standard for optimal serum 25(OH)D concentrations ignores the differing genetically mediated determinates of serum 25(OH)D and may result in ethnic minorities in Western countries having the results of studies done with subjects not representative of ethnic diversity applied to them. Vitamin D levels vary for genetically mediated reasons as well as environmental ones.[30][31][32][33] Among descent groups with heavy sun exposure during their evolution, taking supplemental vitamin D to attain the 25(OH)D level associated with optimal health in studies done with mainly European populations may have deleterious outcomes.[11] A review of vitamin D status in India concluded that studies uniformly point to low 25(OH)D levels in Indians despite abundant sunshine, and suggested a public health need to fortify Indian foods with vitamin D might exist. However the levels found in India are consistent with many other studies of tropical populations which have found that even an extreme amount of sun exposure, such as incured by rural Indians,[34] does not raise 25(OH)D levels to the levels typically found in Europeans,[35][36][37]
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Archives of Dermatology
Large doses of naturally occurring vitamin A ( hypervitaminosis A) can cause a spectrum of toxic effects. Acute toxicity can cause headache and a systemic ...
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Hypervitaminosis D is a potentially serious problem as it can cause permanent kidney damage growth retardation calcification of soft tissues and death Mild symptoms of intoxication are
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Hypervitaminosis A . Hypervitaminosis D. Hyphema Hypocalcemia - infants Hypochondria Hypoglycemia Hypogonadism Hypogonadotropic hypogonadism Hypokalemia Hypokalemic periodic paralysis Hyponatremia Hypoparathyroidism Hypophosphatemia ...
