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Fat soluble vitamins

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Subject: Food fortification, Outline of nutrition, Jack Drummond
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Fat soluble vitamins

A vitamin (US /ˈvtəmɪn/ or UK /ˈvɪtəmɪn/) is an organic compound required by an organism as a vital nutrient in limited amounts.[1] An organic chemical compound (or related set of compounds) is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid (vitamin C) is a vitamin for humans, but not for most other animals, and biotin (vitamin H) and vitamin D are required in the human diet only in certain circumstances.

By convention, the term vitamin includes neither other essential nutrients, such as dietary minerals, essential fatty acids, or essential amino acids (which are needed in larger amounts than vitamins) nor the large number of other nutrients that promote health but are otherwise required less often.[2] Thirteen vitamins are universally recognized at present.




List of vitamins

Each vitamin is typically used in multiple reactions, and, therefore, most have multiple functions.[5]

Vitamin generic
descriptor name
(male, age 19–70)[6]
Deficiency disease Upper Intake Level
Overdose disease Food sources
Vitamin A Retinol, retinal, and
four carotenoids
including beta carotene
Fat 900 µg Night-blindness, Hyperkeratosis, and Keratomalacia[7] 3,000 µg Hypervitaminosis A Orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach, liver, soy milk, milk
Vitamin B1 Thiamine Water 1.2 mg Beriberi, Wernicke-Korsakoff syndrome N/D[8] Drowsiness or muscle relaxation with large doses.[9] Pork, oatmeal, brown rice, vegetables, potatoes, liver, eggs
Vitamin B2 Riboflavin Water 1.3 mg Ariboflavinosis N/D Dairy products, bananas, popcorn, green beans, asparagus
Vitamin B3 Niacin, niacinamide Water 16.0 mg Pellagra 35.0 mg Liver damage (doses > 2g/day)[10] and other problems Meat, fish, eggs, many vegetables, mushrooms, tree nuts
Vitamin B5 Pantothenic acid Water 5.0 mg[11] Paresthesia N/D Diarrhea; possibly nausea and heartburn.[12] Meat, broccoli, avocados
Vitamin B6 Pyridoxine, pyridoxamine, pyridoxal Water 1.3–1.7 mg Anemia[13] peripheral neuropathy. 100 mg Impairment of proprioception, nerve damage (doses > 100 mg/day) Meat, vegetables, tree nuts, bananas
Vitamin B7 Biotin Water 30.0 µg Dermatitis, enteritis N/D Raw egg yolk, liver, peanuts, certain vegetables
Vitamin B12 Cyanocobalamin, hydroxycobalamin, methylcobalamin Water 2.4 µg Megaloblastic anemia[14] N/D Acne-like rash [causality is not conclusively established]. Meat and other animal products
Vitamin D Cholecalciferol, Ergocalciferol Fat 10 µg[15] Rickets and Osteomalacia 50 µg Hypervitaminosis D Fish, eggs, liver, mushrooms
Vitamin E Tocopherols, tocotrienols Fat 15.0 mg Deficiency is very rare; mild hemolytic anemia in newborn infants.[16] 1,000 mg Increased congestive heart failure seen in one large randomized study.[17] Many fruits and vegetables, nuts and seeds
Vitamin K phylloquinone, menaquinones Fat 120 µg Bleeding diathesis N/D Increases coagulation in patients taking warfarin.[18] Leafy green vegetables such as spinach, egg yolks, liver


The term vitamin was derived from "vitamine," a compound word coined in 1912 by the Polish biochemist Kazimierz Funk[19] when working at the Lister Institute of Preventive Medicine. The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This proved incorrect for the micronutrient class, and the word was shortened to vitamin.


The discovery dates of the vitamins and their sources
Year of discovery Vitamin Food source
1913 Vitamin A (Retinol) Cod liver oil
1910 Vitamin B1 (Thiamine) Rice bran
1920 Vitamin C (Ascorbic acid) Citrus, most fresh foods
1920 Vitamin D (Calciferol) Cod liver oil
1920 Vitamin B2 (Riboflavin) Meat, eggs
1922 (Vitamin E) (Tocopherol) Wheat germ oil,
unrefined vegetable oils
1926 Vitamin B12 (Cobalamins) liver, eggs, animal products
1929 Vitamin K1 (Phylloquinone) Leafy green vegetables
1931 Vitamin B5 (Pantothenic acid) Meat, whole grains,
in many foods
1931 Vitamin B7 (Biotin) Meat, dairy products, eggs
1934 Vitamin B6 (Pyridoxine) Meat, dairy products
1936 Vitamin B3 (Niacin) Meat, eggs, grains
1941 Vitamin B9 (Folic acid) Leafy green vegetables

The value of eating a certain food to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding liver to a person would help cure night blindness, an illness now known to be caused by a vitamin A deficiency.[20] The advancement of ocean voyages during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ships' crews.[21]

In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death.[20] In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname Limey for sailors of that organization. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food.[20] As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food.[20]





In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely suspected that "hexuronic acid" was actually vitamin C, and gave a sample to Charles Glen King, who proved its anti-scorbutic activity in his long-established guinea pig scorbutic assay. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A could participate directly in a physiological process.[25]

In humans

Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.[30] Because they are not as readily stored, more consistent intake is important.[31] Many types of water-soluble vitamins are synthesized by bacteria.[32] Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Because they are more likely to accumulate in the body, they are more likely to lead to hypervitaminosis than are water-soluble vitamins. Fat-soluble vitamin regulation is of particular significance in cystic fibrosis.[33]

In nutrition and diseases




Effect of cooking on vitamin content


Vitamin C B1 B2 B3 B5 B6 Folate B12 A E
Average %loss 16 26 −3 18 17 3 20  ? 11 11


Table below shows effects of heat such as heat from boiling, steaming, cooking etc. and other agents on various vitamins. Effect of cutting vegetables can be seen from exposure to air and light. Water soluble vitamins such as B and C seep into the water when a vegetable is boiled.

Vitamin A no partially partially relatively stable
Vitamin C very unstable yes yes yes
Vitamin D no no no no
Vitamin E no yes yes no
Vitamin K no no yes no
Thiamine (B1) highly no  ? > 100°C
Riboflavin (B2) slightly no in solution no
Niacin (B3) yes no no no
Pantothenic Acid (B5) quite stable  ?  ? yes
Vitamin B6 yes  ? yes  ?
Biotin (B7) somewhat  ?  ? no
Folic Acid (B9) yes  ? when dry at high temp
Vitamin B12 yes  ? yes no


Humans must consume vitamins periodically but with differing schedules, to avoid deficiency. The human body's stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts in the human body, mainly in the liver,[16] and an adult human's diet may be deficient in vitamins A and D for many months and B12 in some cases for years, before developing a deficiency condition. However, vitamin B3 (niacin and niacinamide) is not stored in the human body in significant amounts, so stores may last only a couple of weeks.[7][16] For vitamin C, the first symptoms of scurvy in experimental studies of complete vitamin C deprivation in humans have varied widely, from a month to more than six months, depending on previous dietary history that determined body stores.[37]


Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy), and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food and (2) the addition of vitamins and minerals to common foods, often called fortification.[6][16] In addition to these classical vitamin deficiency diseases, some evidence has also suggested links between vitamin deficiency and a number of different disorders.[38][39]

Side-effects and overdose



Compared to vitamins, essential trace minerals are much easier and more dangerous to over-ingest (in proportionate quantities, and especially by supplementation) and thereby develop any of their respective toxicity-conditions.


Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some vitamin supplements is well established for certain health conditions, but others need further study.[43] In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions.[43] Dietary supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.[44]

There have been mixed studies on the importance and safety of dietary supplementation. A meta-analysis published in 2006 suggested that Vitamin A and E supplements not only provide no tangible health benefits for generally healthy individuals but may actually increase mortality, although two large studies included in the analysis involved smokers, for whom it was already known that beta-carotene supplements can be harmful.[45][46][47] Another study published in May 2009 found that antioxidants such as vitamins C and E may actually curb some benefits of exercise.[48] While other findings suggest that evidence of Vitamin E toxicity is limited to specific form taken in excess.[49] A double-blind trial published in 2011 found that vitamin E increases the risk of prostate cancer in healthy men.[50] The conflict of interest section of this study reveals that it has ties to the ambitions of the pharmaceutical companies Merck, Pfizer, Sanofi-Aventis, AstraZeneca, Abbott, GlaxoSmithKline, Janssen, Amgen, Firmagon, and Novartis.[51] Other studies without conflicts of interest reported exactly the opposite – that Vitamin E supplementation reduced the risk of prostate cancer,[52] and increased overall prostate cancer survival.[53]

Governmental regulation of vitamin supplements

Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Regulation of supplements varies widely by country. In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act of 1994.[54] In addition, the Food and Drug Administration uses the Adverse Event Reporting System to monitor adverse events that occur with supplements.[55] In the European Union, the Food Supplements Directive requires that only those supplements that have been proven safe can be sold without a prescription.[56]

Names in current and previous nomenclatures

Nomenclature of reclassified vitamins
Previous name Chemical name Reason for name change[57]
Vitamin B4 Adenine DNA metabolite; synthesized in body
Vitamin B8 Adenylic acid DNA metabolite; synthesized in body
Vitamin F Essential fatty acids Needed in large quantities (does
not fit the definition of a vitamin).
Vitamin G Riboflavin Reclassified as Vitamin B2
Vitamin H Biotin Reclassified as Vitamin B7
Vitamin J Catechol, Flavin Catechol nonessential; flavin reclassified as B2
Vitamin L1[58] Anthranilic acid Non essential
Vitamin L2[58] Adenylthiomethylpentose RNA metabolite; synthesized in body
Vitamin M Folic acid Reclassified as Vitamin B9
Vitamin O Carnitine Synthesized in body
Vitamin P Flavonoids No longer classified as a vitamin
Vitamin PP Niacin Reclassified as Vitamin B3
Vitamin S Salicylic acid Proposed inclusion[59] of salicylate as an essential micronutrient
Vitamin U S-Methylmethionine Protein metabolite; synthesized in body




Main article: Antinutrient

Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in egg whites that inhibits the absorption of biotin.[61] Pyrithiamine is similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.[62]

See also

Food portal


External links

Template:EB1922 Poster

  • USDA RDA chart in PDF format
  • Health Canada Dietary Reference Intakes Reference Chart for Vitamins
  • NIH Office of Dietary Supplements: Fact Sheets
  • NIH Office of Dietary Supplements. Dietary Supplements: Background Information
  • Interactive table based on United States Department of Agriculture Database
  • Vitapred : A web server for predicting vitamin interacting residues in vitamin binding proteins


