Sunday, July 29, 2012

About vitamin K

History, about vitamin K:
In 1929, Danish scientist Henrik Dam investigated the role of cholesterol by feeding chickens a cholesterol-depleted diet. After several weeks, the animals developed hemorrhages and started bleeding. These defects could not be restored by adding purified cholesterol to the diet. It appeared that—together with the cholesterol—a second compound had been extracted from the food, and this compound was called the coagulation vitamin. The new vitamin received the letter K because the initial discoveries were reported in a German journal, in which it was designated as Koagulationsvitamin. Edward Adelbert Doisy of Saint Louis University did much of the research that led to the discovery of the structure and chemical nature of vitamin K. Dam and Doisy shared the 1943 Nobel Prize for medicine for their work on vitamin K (K1 and K2) published in 1939. Several laboratories synthesized the compound(s) in 1939.

The precise function of vitamin K was not discovered until 1974, when three laboratories (Stenflo et al., Nelsestuen et al., and Magnusson et al.) isolated the vitamin K-dependent coagulation factor prothrombin (Factor II) from cows that received a high dose of a vitamin K antagonist, warfarin. It was shown that, while warfarin-treated cows had a form of prothrombin that contained 10 glutamate amino acid residues near the amino terminus of this protein, the normal (untreated) cows contained 10 unusual residues
that were chemically identified as gamma-carboxyglutamate, or Gla. The extra carboxyl group in Gla made clear that vitamin K plays a role in a carboxylation reaction during which Glu is converted into Gla. The biochemistry of how vitamin K is used to convert Glu to Gla has been elucidated over the past thirty years in academic laboratories throughout the world.

About vitamin K
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. They are 2-methyl-1, 4-naphthoquinone (3- ) derivatives. This group of vitamins includes two natural vitamers: vitamin K1 and vitamin K2. The three basic forms of Vitamin K are K1, K2, and K3.

Vitamin K1, also known as phylloquinone or phytomenadione (also called phytonadione), is synthesized by plants, and is found in highest amounts in green leafy vegetables because it is directly involved in photosynthesis.

Vitamin K2 has several subtypes, one of which is involved in bone metabolism. Vitamin K2 homologs (menaquinones) are characterized by the number of isoprenoid residues in their side chain. Menaquinones are abbreviated MK-n, where n represents the number of isoprenoid side chain residues. For example, menaquinone-4 (abbreviated MK-4), has four isoprene residues in its side chain. Bacteria in the colon (large intestine) can produce a range of vitamin K2 forms, and can also convert K1 into K2 (MK-7 homolog). No known toxicity exists for vitamins K1 or K2.

Three synthetic types of vitamin K are known: vitamins K3, K4, and K5. Although the natural K1 and K2 forms are nontoxic, the synthetic form K3 (menadione) has shown toxicity.

Vitamin K deficiency 
Vitamin K deficiency is extremely rare in healthy adults. Newborn infants may have a higher risk until their intestinal bacteria start production. Vitamin K deficiency among infants is potentially dangerous because it can lead to bleeding in the brain and other vital organs. Patients with liver damage or disease, alcoholics, those with cystic fibrosis, inflammatory bowel disease, as well as those who have had surgical procedures in their abdomen have a higher risk of vitamin K deficiency. Some people with eating disorders, such as bulimia have a higher risk of vitamin K deficiency, as well as individuals on very severe or strict diets. Patients taking anticoagulants, salicylates, barbiturates, or cefamandole may also have a higher risk.

Signs and symptoms of vitamin K deficiency may include:

Heavy menstrual bleeding
Anemia
Nose bleeds
Bleeding gums
Osteoporosis is strongly linked to low vitamin K2 levels
Coronary heart disease is strongly linked to low vitamin K2 levels
 
Sources (Vit.K per measure µ grams): 

Kale, frozen, cooked, boiled, drained, without salt: (130grams), 1,147 µgrams.

Kale, cooked, boiled, drained, without salt: (130grams), 1,062 µgrams.

Collards, frozen, chopped, boiled, drained, wo/ salt: (170grams), 1,059 µgrams.

Spinach, frozen, chopped, boiled, drained, wo/ salt: (190grams), 1,027 µgrams.

Spinach, canned, drained solids: (214grams), 988 µgrams.

Spinach, cooked, boiled, drained, without salt: (180grams), 889 µgrams.

Turnip greens, frozen, boiled, drained, wo/ salt: (164grams): 851 µgrams.

Collards, cooked, boiled, drained, without salt: (190grams), 836 µgrams.

Beet greens, cooked, boiled, drained, wo/ salt: (144grams): 697 µgrams.

Turnip greens, cooked, boiled, drained, wo/ salt: (144grams), 529 µgrams.

Mustard greens, cooked, boiled, drained, wo/ salt: (140grams), 419 µgrams.

Brussels sprouts, frozen, boiled, drained, wo/ salt: (155grams), 300 µgrams.

Broccoli, cooked, boiled, drained, without salt: (156grams), 220 µgrams.

Brussels sprouts, cooked, boiled, drained, wo/ salt: (156grams), 219 µgrams.

Onions, spring or scallions (includes tops, bulb), raw: (100grams), 207 µgrams.

Dandelion greens, cooked, boiled, drained, wo/ salt: (105grams), 204 µgrams.

Broccoli, frozen, chopped, boiled, drained, wo/ salt: 184grams), 183 µgrams.

Spinach soufflé: (136grams), 172 µgrams.

Lettuce, butterhead (plus Boston and Bibb types), raw: (163grams), 167 µgrams.

Parsley, raw: (10grams), 164 µgrams.

Spinach, raw: (30 grams), 145 µgrams.

Asparagus, frozen, cooked, boiled, drained, wo/ salt: (180grams), 144 µgrams.

Sauerkraut, canned, solids and liquids: (136grams), 135 µgrams.

Lettuce, iceberg (includes crisp head types), raw: (539grams), 130 µgrams.

Endive, raw: (50grams), 116 µgrams.

Lettuce, green leaf, raw: (56grams): 97 µgrams.

Broccoli, raw: (88grams), 89 µgrams.

Okra, frozen, cooked, boiled, drained, wo/ salt: (184grams), 88 µgrams.

Cabbage, cooked, boiled, drained, without salt: (150grams), 73 µgrams.

Rhubarb, frozen, cooked, with sugar: (240grams), 71 µgrams.

Okra, cooked, boiled, drained, without salt: (160grams ), 64 µgrams.

Cow peas, frozen, boiled, drained, wo/ salt: (170grams), 63 µgrams.

Cabbage, Chinese (pak-choi), boiled, drained, wo/ salt: (170grams), 58 µgrams.

Lettuce, cos or romaine, raw: (56grams): 57 µgrams.

Celery, cooked, boiled, drained, without salt: (150grams), 57 µgrams.

Broccoli, cooked, boiled, drained, without salt: (37grams), 52 µgrams.

Cucumber, with peel, raw: (103grams), 49 µgrams.

Peas, edible-podded, frozen, boiled, drained, wo/ salt: (160grams), 48 µgrams.

Spinach, raw: (10grams), 48 µgrams.

Cabbage, Savoy, raw: (70grams), 48 µgrams.

Asparagus, frozen, cooked, boiled, drained, wo/ salt: (60grams), 48 µgrams.

Cow peas, immature seeds, boiled, drained, wo/ salt: (165grams), 44 µgrams.

Cabbage, raw: (70 grams), 42  µgrams.           

Bread crumbs, dry, grated, seasoned: (120grams), 55 µgrams.

Fast foods, coleslaw: (99grams), 56 µgrams.

Noodles, egg, spinach, cooked, enriched: (160grams), 162 µgrams.

Plums, dried (prunes), stewed, without added sugar: (148grams), 65 µgrams.

Pie crust, cookie-type, prepared from recipe, graham cracker, baked: (139grams), 759 µgrams.

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