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Virsioni dû 15:09, 11 mar 2011

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File:Retinol 3Dstructure.png

Struttura chìmica (mudellu 3D) dô ritinolu, la forma cchiù cumuni ntâ dieta dâ vitamina A.

Na vitamina eni nu cumpostu urgànicu richiestu comu nutrienti n picca dosi di n'urganismu. N àvutri paroli, nu cumpostu urgànicu è chiamatu vitamina siddu nun poti èssiri sintitizzatu n manera sufficienti di l'urganismu, e devi èssiri ottinuta dâ dieta. Pirciò, lu tèrmini dipenni sia dê circustanzi sia di l'urganismu. P'asempiu, l'àcitu ascòrbicu (vitamina C) eni na vitamina ppi l'omu, ma nun ppô cchiossài di l'àutri armali, mentri la biutina e la vitamina D sunnu richiesti ni l'omu n certi circustanzi. Ppi cunvinzioni, lu tèrmini nun includi àvutri nutrienti essenziali comu sali minirali, àciti grassi essenziali, amminuàciti essenziali (picchì chissi sèrvunu n quantitati cchiù granni), e mancu cunteni l'àvutu nùmmuru di àutri nutrienti chi prumòvinu la saluti, puru siddu sunnu richiesti menu spissu. Trìdici vitamini sunnu oj arricanisciuti universalmenti. Li vitamini sunnu dunca classificati dê loru attivitati biològgichi e chìmichi, nun dê loru strutturi. Varî cumposti chi hàvinu attivitati biològgica assuciata cu na vitamina sunnu ditti pruvitamini, e chissi gruppi sunnu numinati cu lèttiri: p'asempiu, la vitamina A cumprenni lu retinali, lu retinolu e quattru carutinòidi canusciuti. Ppi difinizzioni li pruvitamini si pòtinu cunvèrtiri n na forma attiva dâ vitamina ni l'urganismu, e a li voti si pòtinu virè cunvirtiri l'una ni l'àvutra.

Nti l'omu

Li vitamini sunnu classificati n basi â sulubilitati: lipusulùbbili o idrusulùbbili. Nti l'omu sunnu ricanusciuti trìdici vitamini:

4 vitamini lipusulùbbili (A, D, E, K);
9 vitamini idrusulùbbili (8 vitamini B, C).

Vitamini lipusulùbbili

Li sitamini lipusulùbbili sunnu assurbiti attraversu lu ntistinu grazzi a lipidi. Nguasennuca iddi s'accùmulanu facirmenti, eni cchiù fàcili ca pòrtanu a ipirvitaminosi rispettu ê vitamini idrusulùbbili.

Vitamini idrusulùbbili

Li vitamini idrusulùbbili sunnu vilocimenti escreti e difficirmenti assurbiti: ppi chissu, eni mpurtanti nutricàrisi cu cibi ca contèninu cunsistenti quantitati di chissi cumposti di jornu n jornu. Multi vitamini idrusulùbbili sunnu sintitizzati da batteri.

Lista di vitamini nti l'omu

Agni vitamina eni tipicamenti usata n diversi riazzioni, e ppi chissu havi sparaggî funzioni.

Vitamin generic descriptor name	Pruvitamini (lista nun cumpreta)	Sulubbilitati	Dosi giurnaliera cunsigghiata (pô màsculu di 19–70 anni d'etati)^[1]	Malatìi di dificienzi	Upper Intake Level (UL/day)^[1]	Overdose disease
Vitamin A	Retinol, retinal, and four carotenoids including beta carotene	Fat	900 µg	Night-blindness, Hyperkeratosis, and Keratomalacia^[2]	3,000 µg	Hypervitaminosis A
Vitamin B₁	Thiamine	Water	1.2 mg	Beriberi, Wernicke-Korsakoff syndrome	N/D^[3]	Drowsiness or muscle relaxation with large doses.^[4]
Vitamin B₂	Riboflavin	Water	1.3 mg	Ariboflavinosis	N/D
Vitamin B₃	Niacin, niacinamide	Water	16.0 mg	Pellagra	35.0 mg	Liver damage (doses > 2g/day)^[5] and other problems
Vitamin B₅	Pantothenic acid	Water	5.0 mg^[6]	Paresthesia	N/D	Diarrhea; possibly nausea and heartburn.^[7]
Vitamin B₆	Pyridoxine, pyridoxamine, pyridoxal	Water	1.3–1.7 mg	Anemia^[8] peripheral neuropathy.	100 mg	Impairment of proprioception, nerve damage (doses > 100 mg/day)
Vitamin B₇	Biotin	Water	30.0 µg	Dermatitis, enteritis	N/D
Vitamin B₉	Folic acid, folinic acid	Water	400 µg	Megaloblast and Deficiency during pregnancy is associated with birth defects, such as neural tube defects	1,000 µg	May mask symptoms of vitamin B₁₂ deficiency; other effects.
Vitamin B₁₂	Cyanocobalamin, hydroxycobalamin, methylcobalamin	Water	2.4 µg	Megaloblastic anemia^[9]	N/D	Acne-like rash [causality is not conclusively established].
Vitamin C	Ascorbic acid	Water	90.0 mg	Scurvy	2,000 mg	Vitamin C megadosage
Vitamin D	Ergocalciferol, cholecalciferol	Fat	5.0 µg–10 µg^[10]	Rickets and Osteomalacia	50 µg	Hypervitaminosis D
Vitamin E	Tocopherols, tocotrienols	Fat	15.0 mg	Deficiency is very rare; mild hemolytic anemia in newborn infants.^[11]	1,000 mg	Increased congestive heart failure seen in one large randomized study.^[12]
Vitamin K	phylloquinone, menaquinones	Fat	120 µg	Bleeding diathesis	N/D	Increases coagulation in patients taking warfarin.^[13]

↑ ^1,0 ^1,1 Dietary Reference Intakes: Vitamins The National Academies, 2001.
↑ Vitamin and Mineral Supplement Fact Sheets Vitamin A
↑ N/D= "Amount not determinable due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake"(see Dietary Reference Intakes: Vitamins).
↑ Thiamin, vitamin B1: MedlinePlus Supplements. Retrieved on 5 October 2009.
↑ Template:Cite book
↑ Plain type indicates Adequate Intakes (A/I). "The AI is believed to cover the needs of all individuals, but a lack of data prevent being able to specify with confidence the percentage of individuals covered by this intake" (see Dietary Reference Intakes: Vitamins).
↑ Pantothenic acid, dexpanthenol: MedlinePlus Supplements. MedlinePlus. Retrieved on 5 October 2009.
↑ Vitamin and Mineral Supplement Fact Sheets Vitamin B₆
↑ Vitamin and Mineral Supplement Fact Sheets Vitamin B₁₂
↑ Value represents suggested intake without adequate sunlight exposure (see Dietary Reference Intakes: Vitamins).
↑ The Merck Manual: Nutritional Disorders: Vitamin Introduction Please select specific vitamins from the list at the top of the page.
↑ Gaby, Alan R.. "Does vitamin E cause congestive heart failure?", Townsend Letter for Doctors and Patients.
↑ Template:Cite journal

[RDA-1] 1,0 ^1,1 Dietary Reference Intakes: Vitamins The National Academies, 2001.

[GOVa-2] Vitamin and Mineral Supplement Fact Sheets Vitamin A

[3] N/D= "Amount not determinable due to lack of data of adverse effects. Source of intake should be from food only to prevent high levels of intake"(see Dietary Reference Intakes: Vitamins).

[4] Thiamin, vitamin B1: MedlinePlus Supplements. Retrieved on 5 October 2009.

[5] Template:Cite book

[6] Plain type indicates Adequate Intakes (A/I). "The AI is believed to cover the needs of all individuals, but a lack of data prevent being able to specify with confidence the percentage of individuals covered by this intake" (see Dietary Reference Intakes: Vitamins).

[7] Pantothenic acid, dexpanthenol: MedlinePlus Supplements. MedlinePlus. Retrieved on 5 October 2009.

[GOVb6-8] Vitamin and Mineral Supplement Fact Sheets Vitamin B₆

[GOVb12-9] Vitamin and Mineral Supplement Fact Sheets Vitamin B₁₂

[10] Value represents suggested intake without adequate sunlight exposure (see Dietary Reference Intakes: Vitamins).

[Merck-11] The Merck Manual: Nutritional Disorders: Vitamin Introduction Please select specific vitamins from the list at the top of the page.

[12] Gaby, Alan R.. "Does vitamin E cause congestive heart failure?", Townsend Letter for Doctors and Patients.

[13] Template:Cite journal

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Virsioni dû 15:07, 11 mar 2011 cancia 131.114.145.245 (discussioni) →‎Vitamini idrusulùbbili ← Diffirenza pricidenti		Virsioni dû 15:09, 11 mar 2011 cancia annulla Mparu (discussioni \| cuntribbuti) 568 modifiche Nuddu riassuntu dû canciamentu Diffirenza succissiva →
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	[[Mmàggini: Retinol_3Dstructure.png\|thumb\|right\|200px\|Struttura chìmica (mudellu 3D) dô ritinolu, la forma cchiù cumuni ntâ dieta dâ vitamina A.]]		[[Mmàggini: Retinol_3Dstructure.png\|thumb\|right\|200px\|Struttura chìmica (mudellu 3D) dô ritinolu, la forma cchiù cumuni ntâ dieta dâ vitamina A.]]