Fat-Soluble Vitamins: A, D, E, And K
Fat-Soluble Vitamins: A, D, E, and KFact Sheet No. 9.315Food and Nutrition Series Healthby L. Bellows and R. Moore*What are Vitamins?Vitamin A: RetinolVitamins are essential micronutrientsyour body needs in small amounts for variousroles throughout the human body. Vitaminsare divided into two groups: water-soluble(B-complex vitamins and C vitamins) andfat-soluble vitamins (A, D, E and K). Unlikewater-soluble vitamins that need regularreplacement in the body, fat-soluble vitaminsare stored in the liver and fatty tissues, andare eliminated much more slowly than watersoluble vitamins. For more information onwater-soluble vitamins, see fact sheet 9.312Water-Soluble Vitamins: Vitamin B-Complexand Vitamin C.What is Vitamin AVitamin A, also called retinol, has manyfunctions in the body. In addition to helpingthe eyes adjust to light changes, vitamin Aplays an important role in bone growth, toothdevelopment, reproduction, cell division,gene expression, and regulation of theimmune system. The skin, eyes, and mucousmembranes of the mouth, nose, throat andlungs depend on vitamin A to remain moist.Vitamin A is also an important antioxidantthat may play a role in the prevention ofcertain cancers.What are Fat-SolubleVitamins?The fat-soluble vitamins, A, D, E, andK, are stored in the body for long periodsof time and generally pose a greater riskfor toxicity when consumed in excess thanwater-soluble vitamins. Eating a normal,well-balanced diet will not lead to toxicityin otherwise healthy individuals. However,taking vitamin supplements that containmegadoses of vitamins A, D, E and K maylead to toxicity. The body only needs smallamounts of any vitamin.While diseases caused by a lack of fatsoluble vitamins are rare in the United States,symptoms of mild deficiency can developwithout adequate amounts of vitamins inthe diet. Additionally, some health problemsmay decrease the absorption of fat, and inturn, decrease the absorption of vitamins A,D, E and K. Consult a medical professionalabout any potential health problems that mayinterfere with vitamin absorption.L. Bellows, Colorado State University Extension food andnutrition specialist and assistant professor; and R. Moore,graduate student. 11/2012*Food Sources for Vitamin AEating a wide variety of foods is the bestway to ensure that the body gets enoughvitamin A. The retinol, retinal, and retinoicacid forms of vitamin A are suppliedprimarily by foods of animal origin such asdairy products, fish and liver. Some foods ofplant origin contain the antioxidant, betacarotene, which the body converts to vitaminA. Beta-carotene, comes from fruits andvegetables, especially those that are orangeor dark green in color. Vitamin A sourcesalso include carrots, pumpkin, winter squash,dark green leafy vegetables and apricots, all ofwhich are rich in beta-carotene.How much Vitamin AThe recommendation for vitamin Aintake is expressed as micrograms (mcg) ofretinol activity equivalents (RAE). Retinolactivity equivalents account for the fact thatthe body converts only a portion of betacarotene to retinol. One RAE equals 1 mcg ofretinol or 12 mcg of beta-carotene(Table 1). The Recommended DietaryAllowance (RDA) for vitamin A is 900 mcg/day for adult males and 700 mcg/day foradult females.Quick Facts Small amounts of vitaminA, vitamin D, vitamin E andvitamin K are needed tomaintain good health. Fat-soluble vitamins will notbe lost when the foods thatcontain them are cooked. The body does not needthese vitamins every day andstores them in the liver andadipose (fat) tissue when notused. Most people do not needvitamin supplements. Megadoses of vitamins A, D,E or K can be toxic and leadto health problems. Requirements for vitaminsmay be expressed in differentmathematical units. Closeattention should be paid toensure that similar units arebeing compared. Colorado State UniversityExtension. 3/02. Revised 11/12.www.ext.colostate.edu
Compared to vitamin A, it takes twicethe amount of carotene rich foods to meetthe body’s vitamin A requirements, soone may need to increase consumption ofcarotene containing plant foods.Recent studies indicate that vitaminA requirements may be increased due tohyperthyroidism, fever, infection, cold, andexposure to excessive amounts of sunlight.Those that consume excess alcohol or haverenal disease should also increase intake ofvitamin A.Vitamin A DeficiencyVitamin A deficiency in the UnitedStates is rare, but the disease that resultsis known as xerophthalmia. It mostcommonly occurs in developing nationsusually due to malnutrition. Since vitaminA is stored in the liver, it may take up to2 years for signs of deficiency to appear.Night blindness and very dry, rough skinmay indicate a lack of vitamin A. Othersigns of possible vitamin A deficiencyinclude decreased resistance to infections,faulty tooth development, and slower bonegrowth.Too much Vitamin AIn the United States, toxic or excesslevels of vitamin A are more of a concernthan deficiencies. The Tolerable UpperIntake Level (UL) for adults is 3,000 mcgRAE (Table 2). It would be difficult toreach this level consuming food alone,but some multivitamin supplementscontain high doses of vitamin A. If youtake a multivitamin, check the label to besure the majority of vitamin A providedis in the form of beta-carotene, whichappears to be safe. Symptoms of vitamin Atoxicity include dry, itchy skin, headache,nausea, and loss of appetite. Signs of severeoveruse over a short period of time includedizziness, blurred vision and slowedgrowth. Vitamin A toxicity also can causesevere birth defects and may increase therisk for hip fractures.Vitamin DWhat is Vitamin DVitamin D plays a critical role in thebody’s use of calcium and phosphorous. Itworks by increasing the amount of calciumabsorbed from the small intestine, helpingto form and maintain bones. VitaminD benefits the body by playing a role inimmunity and controlling cell growth.Children especially need adequate amountsof vitamin D to develop strong bones andhealthy teeth.Food Sources for Vitamin DThe primary food sources of vitamin Dare milk and other dairy products fortifiedwith vitamin D. Vitamin D is also found inoily fish (e.g., herring, salmon and sardines)as well as in cod liver oil. In additionto the vitamin D provided by food, weobtain vitamin D through our skin whichproduces vitamin D in response to sunlight.How much Vitamin DThe Recommended DietaryAllowance (RDA) for vitamin D appearsas micrograms (mcg) of cholecalciferol(vitamin D3) (Table 1). From 12 monthsto age fifty, the RDA is set at 15 mcg.Twenty mcg of cholecalciferol equals800 International Units (IU), which isthe recommendation for maintenance ofhealthy bone for adults over fifty. Table 1lists additional recommendations forvarious life stages.Exposure to ultraviolet light is necessaryfor the body to produce the active formof vitamin D. Ten to fifteen minutes ofsunlight without sunscreen on the hands,arms and face, twice a week is sufficient toreceive enough vitamin D. This can easilybe obtained in the time spent riding a biketo work or taking a short walk. In order toreduce the risk for skin cancer one shouldapply sunscreen with an SPF of 15 or more,if time in the sun exceeds 10 to 15 minutes.Vitamin D DeficiencySymptoms of vitamin D deficiency ingrowing children include rickets (long, softbowed legs) and flattening of the back ofthe skull. Vitamin D deficiency in adultsmay result in osteomalacia (muscle andbone weakness), and osteoporosis (loss ofbone mass).Recently published data introduces aconcern that some adults and children maybe more prone to developing vitamin Ddeficiency due to an increase in sunscreenuse. In addition, those that live in innercities, wear clothing that covers most ofthe skin, or live in northern climates wherelittle sun is seen in the winter are also proneto vitamin D deficiency. Since most foodshave very low vitamin D levels (unless theyare enriched) a deficiency may be morelikely to develop without adequate exposureto sunlight. Adding fortified foods to thediet such as milk, and for adults includinga supplement, are effective at ensuringadequate vitamin D intake and preventinglow vitamin D levels.Vitamin D deficiency has beenassociated with increased risk ofcommon cancers, autoimmune diseases,hypertension, and infectious disease. Inthe absence of adequate sun exposure, atleast 800 to 1,000 IU of vitamin D3 maybe needed to reach the circulating levelrequired to maximize vitamin D’s benefits.Who is at Risk — These populations mayrequire extra vitamin D in the form ofsupplements or fortified foods: Exclusively breast-fed infants: Humanmilk only provides 25 IU of vitamin Dper liter. All breast-fed and partiallybreast-fed infants should be given avitamin D supplement of 400 IU/day Dark Skin: Those with dark pigmentedskin synthesize less vitamin D uponexposure to sunlight compared tothose with light pigmented skin. Elderly: This population has a reducedability to synthesize vitamin D uponexposure to sunlight, and is alsomore likely to stay indoors and wearsunscreen which blocks vitamin Dsynthesis. Covered and protected skin: Those thatcover all of their skin with clothingwhile outside, and those that wearsunscreen with an SPF factor of 8,block most of the synthesis of vitaminD from sunlight. Disease: Fat malabsorption syndromes,inflammatory bowel disease (IBD),and obesity are all known to result in adecreased ability to absorb and/or usevitamin D in fat stores.Too much Vitamin DThe Tolerable Upper Intake Level (UL)for vitamin D is set at 100 mcg for people 9years of age and older (Table 2). High dosesof vitamin D supplements coupled withlarge amounts of fortified foods may causeaccumulations in the liver and producesigns of poisoning. Signs of vitamin D
toxicity include excess calcium in theblood, slowed mental and physical growth,decreased appetite, nausea and vomiting.It is especially important that infantsand young children do not consume excessamounts of vitamin D regularly, due totheir small body size.Vitamin E: TocopherolWhat is Vitamin EVitamin E benefits the body by actingas an antioxidant, and protecting vitaminsA and C, red blood cells, and essentialfatty acids from destruction. Researchfrom decades ago suggested that takingantioxidant supplements, vitamin E inparticular, might help prevent heart diseaseand cancer. However, newer findingsindicate that people who take antioxidantand vitamin E supplements are not betterprotected against heart disease and cancerthan non-supplement users. Many studiesshow a link between regularly eating anantioxidant rich diet full of fruits andvegetables, and a lower risk for heartdisease, cancer, and several other diseases.Essentially, recent research indicates thatto receive the full benefits of antioxidantsand phytonutrients in the diet, one shouldconsume these compounds in the form offruits and vegetables, not as supplements.Food Sources for Vitamin EAbout 60 percent of vitamin E in thediet comes from vegetable oil (soybean,corn, cottonseed, and safflower). This alsoincludes products made with vegetable oil(margarine and salad dressing). Vitamin Esources also include fruits and vegetables,grains, nuts (almonds and hazelnuts), seeds(sunflower) and fortified cereals.How much Vitamin EThe Recommended Dietary Allowance(RDA) for vitamin E is based on themost active and usable form called alphatocopherol (Table 1). Food and supplementlabels list alpha-tocopherol as the unitInternational units (IU) not in milligrams(mg). One milligram of alpha-tocopherolequals to 1.5 International Units (IU). RDAguidelines state that males and femalesover the age of 14 should receive 15 mcgof alpha-tocopherol per day. Consumingvitamin E in excess of the RDA does notresult in any added benefits.Vitamin E DeficiencyVitamin E deficiency is rare. Cases ofvitamin E deficiency usually only occurin premature infants and in those unableto absorb fats. Since vegetable oils aregood sources of vitamin E, people whoexcessively reduce their total dietary fatmay not get enough vitamin E.Too much Vitamin EThe Tolerable Upper Intake Level(UL) for vitamin E is shown in Table 2.Vitamin E obtained from food usually doesnot pose a risk for toxicity. Supplementalvitamin E is not recommended due to lackof evidence supporting any added healthbenefits. Megadoses of supplementalvitamin E may pose a hazard to peopletaking blood-thinning medications such asCoumadin (also known as warfarin) andthose on statin drugs.Vitamin KWhat is Vitamin KVitamin K is naturally produced bythe bacteria in the intestines, and playsan essential role in normal blood clotting,promoting bone health, and helping toproduce proteins for blood, bones, andkidneys.Food Sources for Vitamin KGood food sources of vitamin K aregreen, leafy-vegetables such as turnipgreens, spinach, cauliflower, cabbageand broccoli, and certain vegetables oilsincluding soybean oil, cottonseed oil,canola oil and olive oil. Animal foods,in general, contain limited amounts ofvitamin K.How much Vitamin KTo help ensure people receive sufficientamounts of vitamin K, an Adequate Intake(AI) has been established for each agegroup (Table 1).Vitamin K DeficiencyWithout sufficient amounts ofvitamin K, hemorrhaging can occur.Vitamin K deficiency may appear in infantsor in people who take anticoagulants, suchas Coumadin (warfarin), or antibioticdrugs. Newborn babies lack the intestinalbacteria to produce vitamin K and needa supplement for the first week. Thoseon anticoagulant drugs (blood thinners)may become vitamin K deficient, butshould not change their vitamin K intakewithout consulting a physician. Peopletaking antibiotics may lack vitamin Ktemporarily because intestinal bacteria aresometimes killed as a result of long-termuse of antibiotics. Also, people with chronicdiarrhea may have problems absorbingsufficient amounts of vitamin K throughthe intestine and should consult theirphysician to determine if supplementationis necessary.Too much Vitamin KAlthough no Tolerable Upper IntakeLevel (UL) has been established forvitamin K, excessive amounts can causethe breakdown of red blood cells and liverdamage. People taking blood-thinningdrugs or anticoagulants should moderatetheir intake of foods with vitamin K,because excess vitamin K can alter bloodclotting times. Large doses of vitamin K arenot advised.Summary Fat-soluble vitamins: A, D, E, andK — are stored in the body for longperiods of time, and pose a greaterrisk for toxicity than water-solublevitamins. Fat-soluble vitamins areonly needed in small amounts.Beta carotene is an importantantioxidant that the body convertsto Vitamin A, and it is found in avariety of fruits and vegetables.Inadequate dietary consumptionof vitamin D, along with limitedsun exposure, makes vitamin Ddeficiency a growing public healthconcern.Vitamin E benefits the body byacting as an antioxidant, andresearch indicates that it mayoffer a protective effect if obtainedthrough a diet rich in fruitsand vegetables, as opposed to asupplement or multivitamin.The bacteria in our gut producevitamin K, and it is also found ingreen leafy vegetables.
Table 1. Recommended Dietary Intake (RDA) and Adequate Intake (AI) for Fat-Soluble VitaminsLife Stage GroupVitamin A(mcg1/RAE)Vitamin D(mcg2)Vitamin E(mcg a-TE3)Vitamin K(mcg)0 - 6mo400*10*4*2.0*6mo - 12mo500*10*5*2.5*1 - 3y30015630*4 - 8y40015755*9 - 13y600151160*14 - 18y900151575*19 - 30y9001515120*31 - 50y9001515120*51 - 70y9001515120* 70y9002015120*9 - 13y600151160*14 - 18y700151575*19 - 30y700151590*31 - 50y700151590*51 - 70y700151590* 70y700201590*14 - 18y75015157519 - 30y77015159031 - 50y77015159014 - 18y120015197519 - 30y130015199031 - actationAs retinol activity equivalents (RAEs). 1 RAE 1mcg retinol or 12 mcg beta-carotene.1As cholecalciferol (vitamin D3). 10 mcg cholecalciferol 400 IU of Vitamin D.2As alpha-tocopherol equivalents. 1 mg of alpha-tocopherol 1.5 IU of Vitamin E 22IU of d-alpha-tocopherol 33 IU of dl-alpha- tocopherol3At 6 months of age, infants may be introduced to solid foods while remaining on formula or breast milk. There may be some overlap in specificnutrient requirements.4*Indicates an Adequate Intake (AI). All other values are Recommended Dietary Allowance (RDA).
Table 2. Tolerable Upper Intake Levels (UL) for Fat-Soluble VitaminsLife Stage GroupVitamin A(mcg/d)Vitamin D(mcg/d)Vitamin E(mg a-TE)Vitamin K*0 - 6mo60025ND2ND6mo - 12mo60038NDND1 - 3y60063200ND4 - 8y90075300ND9 - 13y1700100600ND14 - 18y2800100800ND19 - 70y30001001000ND 70y30001001000ND 182800100800ND19 - ant and LactatingAt 6 months of age, infants may be introduced to solid foods while remaining on formula or breast milk. There may be some overlap in specificnutrient requirements.1ND not determinable due to insufficient data2*An UL for vitamin K was not established.ReferencesAdvanced Nutrition: Macronutrients,Micronutrients, and Metabolism (2009).CRC Press, Taylor & Francis Group.Advanced Nutrition and HumanMetabolism (2009). Wadsworth,Cengage Learning.Biochemical, Physiological, MolecularAspects of Human Nutrition (2006).Saunders, Elsevier Inc.Dietary Reference Intakes for Calcium andVitamin D. Washington, DC: NationalAcademy Press, 2011.Dietary Reference Intakes for Vitamin C,Vitamin E, Selenium, and Carotenoids.Washington, DC: National AcademyPress, 2000.Dietary Reference Intakes for Vitamin A,Vitamin K, Arsenic, Boron, Chromium,Copper, Iodine, Iron, Manganese,Molybdenum, Nickel, Silicon,Vanadium, and Zinc. Washington, DC:National Academy Press, 2001.Dietary Supplements: What you needto know (2011). NIH ClinicalCenter. Available on eedToKnow.aspxDuyff, ADA . American DieteticAssociation: Complete Food andNutrition Guide. Hoboken: John Wiley& Sons, Inc., 2006. Ebook Library Web.02 Oct. 2012.Holick, M.F. and Chen, T.C. Vitamin Ddeficiency: a worldwide problem withhealth consequences. American Journalof Clinical Nutrition. 2008. April 87 (4):1080S-6S.U.S. Department of Agriculture andU.S. Department of Health andHuman Services. Dietary Guidelinesfor Americans, 2010. 7th Edition,Washington, DC: U.S. GovernmentPrinting Office, December 2010.Wagner CL, Greer FR. American Academyof Pediatrics, Section on Breastfeedingand Committee on Nutrition.Prevention of rickets and vitamin Ddeficiency in infants, children, andadolescents. Pediatrics. 2008; 122(5):1142–1152.Colorado State University, U.S. Department ofAgriculture and Colorado counties cooperating.CSU Extension programs are available to all withoutdiscrimination. No endorsement of products mentionedis intended nor is criticism implied of products notmentioned.
D, E and K. Consult a medical professional about any potential health problems that may interfere with vitamin absorption. Quick Facts Small amounts of vitamin A, vitamin D, vitamin E and vitamin K are needed to maintain good health. Fat-soluble vitamins will not be lost when the foods
the processes by which other nutrients are digested, absorbed, and metabolized or built into body structures. The only disease a vitamin can cure is the . Vitamins. Definition and Classification of Vitamins Vitamins fall into 2 classes, fat soluble and water soluble. Vitamin Precursors Some vitamins exist as precursors, or provitamins. Fat .
Water soluble vitamins include vitamins B1, B2, B3, B6, B12, vitamin C, biotin and folate. Fat soluble vitamins include vitamins A, D, E and K. In pregnancy, sufficient and proper amount of both .
MEDICINAL CHEMISTRY 562P - VITAMINS (and Minerals) Allan Rettie (rettie@u.washington.edu) – Fat-soluble vitamins Bill Atkins (winky@u.washington.edu) – Water-soluble vitamins INTRODUCTION I. Definitions Vitamins are organic compounds and minerals are chemical elements that are
Vitamins A, E and Carotenoids Background Information Sources and Physiological Functions. Vitamins A (retinol) and E (alpha-tocopherol) and the carotenoids are fat-soluble micronutrients found in many foods, including some vegetables, fruits, meats, and animal products. Fish-liver oils, liver, egg yolks, butter, and cream are known
Sports Nutrition Lesson 4 Vitamins Thirteen different vitamins have been identified and studied to date. They are classed as either fat-soluble (vitamins A, D, E, K) or water-soluble (vitamin B complex, vitamin C). Together they are respon
35 1993). Traditionally, vitamins are categorized based on their solubility properties: Vitamin C and most of 36 the B-vitamin complex group compounds are water-soluble while vitamins A, D, E, and K are fat-soluble. 37 In Figures 1 and 2, the structures of vitamin D 3 (cholecalciferol) and vitamin C (ascorbic acid) are presented
429 Calories 152 Calories From Fat 17g Total Fat 2.5g Saturated Fat 8.3g Protein 58g Carbs 0.7g Sugars fresh greens 23 Calories 0 Calories From Fat 0g Total Fat 0g Saturated Fat 1.2g Protein 4.7g Carbs 2.4g Sugars brown rice 318 Calories 20 Calories From Fat 2.4g Total Fat
not know; am I my brother’s keeper?’ (Genesis 4:9) N NOVEMBER 2014 the Obama administration in the United States announced an extension of relief for immigrant families, prompting one cartoonist to caricature ‘an immigrant family climbing through a window to crash a white family’s Thanksgiving dinner’ with the ‘white father unhappily telling his family, “Thanks to the president .
