what are vitamins

7/24/2019 What Are Vitamins

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What are Vitamins?

Vitamins are essential micronutrients your body needs in small amounts forvarious roles throughout the human body. Vitamins are divided into two groups:water-soluble (B-complex vitamins and C vitamins) and fat-soluble vitamins (!"! # and $). %nli&e water-soluble vitamins that need regular replacement in thebody! fat-soluble vitamins are stored in the liver and fatty tissues! and areeliminated much more slowly than watersoluble vitamins. 'or more informationon water-soluble vitamins! see fact sheet .*+ ,ater-oluble Vitamins: VitaminB-Complex and Vitamin C.

What are Fat-Soluble Vitamins?

he fat-soluble vitamins! ! "! #! and $! are stored in the body for long periods oftime and generally pose a greater ris& for toxicity when consumed in excess thanwater-soluble vitamins. #ating a normal! well-balanced diet will not lead totoxicity in otherwise healthy individuals. /owever! ta&ing vitamin supplements

that contain megadoses of vitamins ! "! # and $ may lead to toxicity. he bodyonly needs small amounts of any vitamin.

,hile diseases caused by a lac& of fat-soluble vitamins are rare in the %nitedtates! symptoms of mild de0ciency can develop without ade1uate amounts ofvitamins in the diet. dditionally! some health problems may decrease theabsorption of fat! and in turn! decrease the absorption of vitamins ! "! # and $.Consult a medical professional about any potential health problems that mayinterfere with vitamin absorption.

Vitamin A: Retinol

What is Vitamin AVitamin ! also called retinol! has manyfunctions in the body. 2n addition to helping theeyes ad3ust to light changes! vitamin playsan important role in bone growth! toothdevelopment! reproduction! cell division! geneexpression! and regulation of the immunesystem. he s&in! eyes! and mucousmembranes of the mouth! nose! throat andlungs depend on vitamin to remain moist. Vitamin is also an importantantioxidant that may play a role in the prevention of certain cancers.

Food Sources for Vitamin A

#ating a wide variety of foods is the best way to ensure that the body getsenough vitamin . he retinol! retinal! and retinoic acid forms of vitamin aresupplied primarily by foods of animal origin such as dairy products! 0sh and liver.ome foods of plant origin contain the antioxidant! betacarotene! which the bodyconverts to vitamin . Beta-carotene! comes from fruits and vegetables!especially those that are orange or dar& green in color. Vitamin sources alsoinclude carrots! pump&in! winter s1uash! dar& green leafy vegetables andapricots! all of which are rich in beta-carotene.

How much Vitamin A
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he recommendation for vitamin inta&e is expressed as micrograms (mcg) ofretinol activity e1uivalents (4#). 4etinol activity e1uivalents account for the factthat the body converts only a portion of betacarotene to retinol. 5ne 4# e1uals* mcg of retinol or *+ mcg of beta-carotene (able *). he 4ecommended "ietaryllowance (4") for vitamin is 66 mcg7 day for adult males and 866 mcg7day

for adult females.

Compared to vitamin ! it ta&es twice the amount of carotene rich foods to meetthe body9s vitamin re1uirements! so one may need to increase consumption ofcarotene containing plant foods.

4ecent studies indicate that vitamin re1uirements may be increased due tohyperthyroidism! fever! infection! cold! and exposure to excessive amounts ofsunlight. hose that consume excess alcohol or have renal disease should alsoincrease inta&e of vitamin .

Vitamin A Deciency

Vitamin de0ciency in the %nited tates is rare! but the disease that results is&nown as xerophthalmia. 2t most commonly occurs in developing nations usuallydue to malnutrition. ince vitamin is stored in the liver! it may ta&e up to +years for signs of de0ciency to appear. ight blindness and very dry! rough s&inmay indicate a lac& of vitamin . 5ther signs of possible vitamin de0ciencyinclude decreased resistance to infections! faulty tooth development! and slowerbone growth.

oo much Vitamin A

2n the %nited tates! toxic or excess levels of vitamin are more of a concern

than de0ciencies. he olerable %pper 2nta&e ;evel (%;) for adults is !666 mcg4# (able +). 2t would be di


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he primary food sources of vitamin " are mil& and other dairy products forti0edwith vitamin ". Vitamin " is also found in oily 0sh (e.g.! herring! salmon andsardines) as well as in cod liver oil. 2n addition to the vitamin " provided by food!we obtain vitamin " through our s&in which produces vitamin " in response tosunlight.

How much Vitamin D

he 4ecommended "ietary llowance (4") for vitamin " appears asmicrograms (mcg) of cholecalciferol (vitamin ") (able *). 'rom *+ months toage 0fty! the 4" is set at *> mcg. wenty mcg of cholecalciferol e1uals ?662nternational %nits (2%)! which is the recommendation for maintenance of healthybone for adults over 0fty. able * lists additional recommendations for various lifestages.

#xposure to ultraviolet light is necessary for the body to produce the active formof vitamin ". en to 0fteen minutes of sunlight without sunscreen on the hands!

arms and face! twice a wee& is su 2% of vitamin

" per liter. ll breast-fed and partially breast-fed infants should be given avitamin " supplement of D66 2%7day

Dark Skin: hose with dar& pigmented s&in synthesi=e less vitamin " upon

exposure to sunlight compared to those with light pigmented s&in.


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Elderly: his population has a reduced ability to synthesi=e vitamin " upon

exposure to sunlight! and is also more li&ely to stay indoors and wearsunscreen which bloc&s vitamin " synthesis.

Covered and protected skin: hose that cover all of their s&in with clothing

while outside! and those that wear sunscreen with an @' factor of ?! bloc&most of the synthesis of vitamin " from sunlight.

Disease: 'at malabsorption syndromes! inAammatory bowel disease (2B")!

and obesity are all &nown to result in a decreased ability to absorb and7oruse vitamin " in fat stores.

oo much Vitamin D

he olerable %pper 2nta&e ;evel (%;) for vitamin " is set at *66 mcg for people years of age and older (able +). /igh doses of vitamin " supplements coupled

with large amounts of forti0ed foods may cause accumulations in the liver andproduce signs of poisoning. igns of vitamin " toxicity include excess calcium inthe blood! slowed mental and physical growth! decreased appetite! nausea andvomiting.

2t is especially important that infants and young children do not consume excessamounts of vitamin " regularly! due to their small body si=e.

Vitamin ": oco#herol

What is Vitamin "

Vitamin # bene0ts the body by acting as an antioxidant! and protecting vitamins and C! red blood cells! and essential fatty acids from destruction. 4esearchfrom decades ago suggested that ta&ing antioxidant supplements! vitamin # inparticular! might help prevent heart disease and cancer. /owever! newer 0ndingsindicate that people who ta&e antioxidant and vitamin # supplements are notbetter protected against heart disease and cancer than non-supplement users.Eany studies show a lin& between regularly eating an antioxidant rich diet full offruits and vegetables! and a lower ris& for heart disease! cancer! and severalother diseases. #ssentially! recent research indicates that to receive the fullbene0ts of antioxidants and phytonutrients in the diet! one should consumethese compounds in the form of fruits and vegetables! not as supplements.

Food Sources for Vitamin "

bout F6 percent of vitamin # in the diet comes from vegetable oil (soybean!corn! cottonseed! and saGower). his also includes products made withvegetable oil (margarine and salad dressing). Vitamin # sources also includefruits and vegetables! grains! nuts (almonds and ha=elnuts)! seeds (sunAower)and forti0ed cereals.

How much Vitamin "

he 4ecommended "ietary llowance (4") for vitamin # is based on the mostactive and usable form called alpha-tocopherol (able *). 'ood and supplement

labels list alpha-tocopherol as the unit 2nternational units (2%) not in milligrams(mg). 5ne milligram of alpha-tocopherol e1uals to *.> 2nternational %nits (2%).


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4" guidelines state that males and females over the age of *D should receive*> mcg of alpha-tocopherol per day. Consuming vitamin # in excess of the 4"does not result in any added bene0ts.

Vitamin " Deciency

Vitamin # de0ciency is rare. Cases of vitamin # de0ciency usually only occur inpremature infants and in those unable to absorb fats. ince vegetable oils aregood sources of vitamin #! people who excessively reduce their total dietary fatmay not get enough vitamin #.

oo much Vitamin "

he olerable %pper 2nta&e ;evel (%;) for vitamin # is shown in able +. Vitamin #obtained from food usually does not pose a ris& for toxicity. upplementalvitamin # is not recommended due to lac& of evidence supporting any addedhealth bene0ts. Eegadoses of supplemental vitamin # may pose a ha=ard topeople ta&ing blood-thinning medications such as Coumadin (also &nown as

warfarin) and those on statin drugs.

Vitamin $

What is Vitamin $

Vitamin $ is naturally produced by the bacteria in the intestines! and plays anessential role in normal blood clotting! promoting bone health! and helping toproduce proteins for blood! bones! and &idneys.

Food Sources for Vitamin $

Hood food sources of vitamin $ are green! leafy-vegetables such as turnipgreens! spinach! cauliAower! cabbage and broccoli! and certain vegetables oilsincluding soybean oil! cottonseed oil! canola oil and olive oil. nimal foods! ingeneral! contain limited amounts of vitamin $.

How much Vitamin $

o help ensure people receive su


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lthough no olerable %pper 2nta&e ;evel (%;) has been established for vitamin $!excessive amounts can cause the brea&down of red blood cells and liverdamage. @eople ta&ing blood-thinning drugs or anticoagulants should moderatetheir inta&e of foods with vitamin $! because excess vitamin $ can alter bloodclotting times. ;arge doses of vitamin $ are not advised.

Summary

'at-soluble vitamins: ! "! #! and $ are stored in the body for long

periods of time! and pose a greater ris& for toxicity than water-solublevitamins. 'at-soluble vitamins are only needed in small amounts.

Beta carotene is an important antioxidant that the body converts to

Vitamin ! and it is found in a variety of fruits and vegetables.

2nade1uate dietary consumption of vitamin "! along with limited sun

exposure! ma&es vitamin " de0ciency a growing public health concern.

Vitamin # bene0ts the body by acting as an antioxidant! and researchindicates that it may oer a protective eect if obtained through a dietrich in fruits and vegetables! as opposed to a supplement or multivitamin.

he bacteria in our gut produce vitamin $! and it is also found in green

leafy vegetables.

able %& Recommended Dietary 'nta!e (RDA) and Ade*uate 'nta!e (A')

for Fat-Soluble Vitamins

;ife tageHroup

Vitamin (mcg*74#)

Vitamin"(mcg+)

Vitamin #(mcg a-

#)

Vitamin $(mcg)

2nfantsD

6 - Fmo D66I *6I DI +.6I

Fmo - *+mo >66I *6I >I +.>I

Children

* - y 66 *> F 6I

D - ?y D66 *> 8 >>I

Eales

- *y F66 *> ** F6I

*D - *?y 66 *> *> 8>I

* - 6y 66 *> *> *+6I

* - >6y 66 *> *> *+6I


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>* - 86y 66 *> *> *+6I

J86y 66 +6 *> *+6I

'emales

- *y F66 *> ** F6I

*D - *?y 866 *> *> 8>I

* - 6y 866 *> *> 6I

* - >6y 866 *> *> 6I

>* - 86y 866 *> *> 6I

J86y 866 +6 *> 6I

@regnant

*D - *?y 8>6 *> *> 8>

* - 6y 886 *> *> 6

* - >6y 886 *> *> 6

;actation

*D - *?y *+66 *> * 8>

* - 6y *66 *> * 6

* - >6y *66 *> * 6

*s retinol activity e1uivalents (4#s). * 4# K *mcg retinol or *+ mcg beta-carotene.

+s cholecalciferol (vitamin "). *6 mcg cholecalciferol K D66 2% of Vitamin ".

s alpha-tocopherol e1uivalents. * mg of alpha-tocopherol K *.> 2% of Vitamin#K++2% of d-alpha-tocopherolK 2% of dl-alpha- tocopherol

Dt F months of age! infants may be introduced to solid foods while remaining onformula or breast mil&. here may be some overlap in speci0c nutrientre1uirements.

I2ndicates an de1uate 2nta&e (2). ll other values are 4ecommended "ietaryllowance (4").

able +& olerable ,##er 'nta!e e.els (,) for Fat-Soluble Vitamins

;ife tage Hroup Vitamin (mcg7d)

Vitamin "(mcg7d)

Vitamin #(mg a-#)

Vitamin $I

2nfants*


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6 - Fmo F66 +> "+ "

Fmo - *+mo F66 ? " "

Children

* - y F66 F +66 "

D - ?y 66 8> 66 "

Eales7'emales

- *y *866 *66 F66 "

*D - *?y +?66 *66 ?66 "

* - 86y 666 *66 *666 "

J86y 666 *66 *666 "

@regnant and ;actating

L*? +?66 *66 ?66 "

* - >6y 666 *66 *666 "

*t F months of age! infants may be introduced to solid foods while remaining on

formula or breast mil&. here may be some overlap in speci0c nutrientre1uirements.

+" K not determinable due to insu


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"ietary upplements: ,hat you need to &now (+6**). 2/ Clinical Center.vailable onhttp:77ods.od.nih.gov7/ealth2nformation7"O,hatPoueedo$now.aspx

"uy! " . merican "ietetic ssociation: Complete 'ood and utrition Huide./obo&en: Qohn ,iley M ons! 2nc.! +66F. #boo& ;ibrary ,eb. 6+ 5ct. +6*+.

/olic&! E.'. and Chen! .C. Vitamin " de0ciency: a worldwide problem with healthconse1uences. merican Qournal of Clinical utrition. +66?. pril ?8 (D): *6?6-F.

%.. "epartment of griculture and %.. "epartment of /ealth and /umanervices. "ietary Huidelines for mericans! +6*6. 8th #dition! ,ashington! "C:%.. Hovernment @rinting 5): **D+S**>+.
http://ods.od.nih.gov/HealthInformation/DS_WhatYouNeedToKnow.aspxhttp://ods.od.nih.gov/HealthInformation/DS_WhatYouNeedToKnow.aspx

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