Vitamins come from a number of sources including fresh fruit and vegetables ( Vitamin C ), carrots, liver ( Vitamin A ), cereal bran, bread, liver e ( B vitamins ), fish liver oil ( Vitamin D ) and fresh green vegetables ( Vitamin K ).

Vitamin E and vitamin K, as well as the ubiquinones, are examples of this class.

Some are produced by the human body with adequate precursors ( glutathione, Vitamin C ), and those the body cannot produce may only be obtained in the diet via direct sources ( Vitamin C in humans, Vitamin A, Vitamin K ) or produced by the body from other compounds ( Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight ).

Vitamin K prevents bone loss and / or fractures in those with postmenopausal osteoporosis,

** ketamine ( K ; Ketalar, Ketaset, Ketanest ; " Ket ", " Kit Kat ", " Special-K ", " Vitamin K ", " Jet Fuel ", " Horse Tranquilizer ")

Vitamin K < sub > 1 </ sub > ( phylloquinone ).

Vitamin K < sub > 2 </ sub > ( menaquinone ).

Vitamin K is a group of structurally similar, fat-soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue.

The three basic forms of Vitamin K are K1, K2, and K3.

Vitamin K < sub > 1 </ sub >, also known as phylloquinone or phytomenadione ( also called phytonadione ),

Vitamin K < sub > 2 </ sub > has several subtypes, one of which is involved in bone metabolism.

Vitamin K < sub > 2 </ sub > homologs ( menaquinones ) are characterized by the number of isoprenoid residues in their side chain.

Vitamin K was identified in 1929 by Danish scientist Henrik Dam when he investigated the role of cholesterol by feeding chickens a cholesterol-depleted diet.

Vitamin K < sub > 2 </ sub > ( menaquinone ) includes several subtypes ; two subtypes most studied are menaquinone-4 ( menatetrenone, MK4 ) and menaquinone-7 ( MK7 ).

Vitamin K < sub > 2 </ sub > ( MK4, but not MK7 or vitamin K < sub > 1 </ sub >) has also been shown to prevent bone loss and / or fractures in the following circumstances:

Vitamin C is especially prone to oxidation during cooking and may be completely destroyed by protracted cooking.

Scurvy is a disease now known to be caused by a deficiency of Vitamin C, but in Lind's day, the concept of vitamins was unknown.

Vitamin C is necessary for the maintenance of healthy connective tissue.

Although plant-derived foods do not naturally contain B < sub > 12 </ sub >, some are fortified during processing with added B < sub > 12 </ sub > and other nutrients .< ref > Vitamin A, in the form of beta-carotene, is available from plants such as carrots and spinach.

( Vitamin D is the exception: it can be synthesized in the skin, in the presence of UVB radiation.

Some cannot be present in certain areas of free radical development ( Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas ).

* Vitamin D deficiency: Low circulating Vitamin D is common among the elderly worldwide.

In renal disease, more active forms of Vitamin D such as cholecalciferol or ( 1, 25-dihydroxycholecalciferol or calcitriol which is the main biologically active form of vitamin D ) is used, as the kidney cannot adequately generate calcitriol from calcidiol ( 25-hydroxycholecalciferol ) which is the storage form of vitamin D. In vitamin D assays, vitamin D < sub > 2 </ sub > ( ergocalitrol ) is not accurately measured, therefore vitamin D < sub > 3 </ sub > ( cholecalciferol ) is recommended for supplementation.

In contrast to these coordination compounds, methylcobalamin ( a form of Vitamin B < sub > 12 </ sub >), with a cobalt-methyl bond, is a true organometallic complex, one of the few known in biology.

The rose hip, usually from R. canina is used as a minor source of Vitamin C. The fruits of many species have significant levels of vitamins and have been used as a food supplement.

For example, a teaspoon of paprika contains about 1133 IU of Vitamin A, which is over 20 % of the recommended daily allowance specified by the US FDA.

Vitamin C is widespread in plant tissues, with particularly high concentrations occurring in citrus fruits ( oranges, lemons, limes, grapefruits ), tomatoes, potatoes, cabbages, and green peppers.

Vitamin C is destroyed by the process of pasteurization, so babies fed with ordinary bottled milk sometimes suffer from scurvy if they are not provided with adequate vitamin supplements.

Vitamin K < sub > 1 </ sub >, the precursor of most vitamin K in nature, is a steroisomer of phylloquinone, an important chemical in green plants, where it functions as an electron accepter in photosystem I during photosynthesis.

Vitamin K ( in animals ) is involved in the carboxylation of certain glutamate residues in proteins to form gamma-carboxyglutamate ( Gla ) residues.

Raw cranberries have moderate levels of Vitamin C, dietary fiber and the essential dietary mineral, manganese, as well as a balanced profile of other essential micronutrients.

Vitamin B < sub > 6 </ sub > is an essential component of enzymes that facilitate the biosynthesis of sphingolipids.

In mango fruit pulp, the antioxidant vitamins A and C, Vitamin B < sub > 6 </ sub > ( pyridoxine ), folate, other B vitamins and essential nutrients, such as potassium, copper and amino acids, are present.

* Vitamin C, an essential nutrient

It is, however, an essential nutrient for human beings, who require external sources of ascorbic acid ( known as Vitamin C in the context of nutrition ).

Likewise, boron and magnesium are considered essential for the bioavailability and absorption of Vitamin D and calcium.

Wheat germ is a concentrated source of several essential nutrients including Vitamin E, folate ( folic acid ), phosphorus, thiamin, zinc and magnesium, as well as essential fatty acids and fatty alcohols.

Vitamin K is essential for the hepatic synthesis of Factors II ( prothrombin ), VII, IX and X.

Good quality supplements should contain at least 8 essential vitamins ( Vitamin A, B-complex, D, and E, and B vitamins ).

A potential confounding factor is the form of Vitamin E used in these studies.

Deficiency of Vitamin K may also contribute to bleeding disorders because clotting factor maturation depends on Vitamin K.

Vitamin C supplementation also appeared to normalize several age-related molecular markers such as the increased levels of the transcription factor NF-κB.

* Vitamin B < sub > 11 </ sub >: pteryl-hepta-glutamic acid — chick growth factor, which is a form of folic acid.

* Vitamin B < sub > 14 </ sub >: cell proliferant, anti-anemia, rat growth factor, and antitumor pterin phosphate named by Earl R. Norris.

* Vitamin B < sub > m </ sub >: " mouse factor ": also used to designate inositol

Vitamin B12 can then bind to intrinsic factor ( IF ) that has been produced by parietal cells.

Intrinsic factor ( IF ) produced by the parietal cells then binds Vitamin B12, creating a Vit.