Vitamin K

From Cookipedia

Brussels sprouts are very high in 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.

Vitamin K1, also known as phylloquinone, phytomenadione, or phytonadione, is synthesized by plants, and is found in highest amounts in green leafy vegetables because it is directly involved in photosynthesis. It may be thought of as the "plant form" of vitamin K.

It is active in animals since animals can easily convert it to vitamin K2. Previous theory held that dietary deficiency is extremely rare unless the intestine (small bowel) was heavily damaged, resulting in malabsorption of the molecule. The other at-risk group for deficiency were those subject to decreased production of K2 by normal flora, as seen in broad spectrum antibiotic use. Taking broad-spectrum antibiotics can reduce vitamin K production in the gut by nearly 74% in people compared with those not taking these antibiotics. Diets low in vitamin K also decrease the body's vitamin K concentration. Additionally, in the elderly there is a reduction in vitamin K2 production.

Recent research results also demonstrate that the small intestine and large intestine (colon) seem to be inefficient at absorbing vitamin K. These results are reinforced by human cohort studies, where a majority of the subjects showed inadequate vitamin K amounts in the body. This was revealed by the presence of large amounts of incomplete gamma-carboxylated proteins in the blood, an indirect test for vitamin K deficiency. And in an animal model MK4 was shown to prevent arterial calcifications, pointing to its potential role in cardiovascular disease prevention. In this study vitamin K1 was also tested, in an attempt to make connections between Vitamin K1 intake and calcification reduction. No connections were made in this study.

Vitamin K recommended amounts [RDA]

The U.S. Dietary Reference Intake (DRI) for an Adequate Intake (AI) of vitamin K is:

  • 120 micrograms/day for a 25-year old male.
  • 90 micrograms/day for adult women
  • 15–100 micrograms/day for children and adolescents
  • 10–20 micrograms/day for infants

Sources of vitamin K in food

Food Serving Size Vitamin K1 Microgram (μg) Food Serving Size Vitamin K1 Microgram (μg)
Kale, cooked 1/2 cup 531 Parsley, raw 1/4 cup 246
Spinach, cooked 1/2 cup 444 Spinach, raw 1 cup 145
Collards, cooked 1/2 cup 418 Collards, raw 1 cup 184
Swiss chard, cooked 1/2 cup 287 Swiss chard, raw 1 cup 299
Mustard greens, cooked 1/2 cup 210 Mustard greens, raw 1 cup 279
Turnip greens, cooked 1/2 cup 265 Turnip greens, raw 1 cup 138
Broccoli, cooked 1 cup 220 Broccoli, raw 1 cup 89
Brussels sprouts, cooked 1 cup 219 Endive, raw 1 cup 116
Cabbage, cooked 1/2 cup 82 Green leaf lettuce 1 cup 71
Asparagus 4 spears 48 Romaine lettuce, raw 1 cup 57
Food 3 ½ ounce portion Microgram (μg) Proportion of vitamin K2 Food 3 ½ ounce portion Microgram (μg) Proportion of vitamin K2
Natto, cooked 1,103.4 (90% MK-7, 10% other MK) Chicken Leg 8.5 (100% MK-4)
Goose liver pâté 369.0 (100% MK-4) Ground beef (medium fat) 8.1 (100% MK-4)
Hard cheeses (Dutch Gouda style), raw 76.3 (6% MK-4, 94% other MK) Chicken liver (braised) 6.7 (100% MK-4)
Soft cheeses (French Brie style) 56.5 (6.5 MK-4, 93.5% other MK Hot dog 5.7 (100% MK-4)
Egg yolk, (Netherlands) 32.1 (98% MK-4, 2% other MK) Bacon 5.6 (100% MK-4)
Goose leg 31.0 (100% MK-4) Calf’s liver (pan fried) 6.0 (100% MK-4)
Egg yolk (U.S.) 15.5 (100% MK-4) Sauerkraut 4.8 (100% MK-4)
Butter 15.0 (100% MK-4) Whole milk 1.0 (100% MK-4)
Chicken liver (raw) 14.1 (100% MK-4) Salmon (Alaska, Coho, Sockeye, Chum and King wild (raw)) 0.5 (100% MK-4)
Chicken liver (pan fried) 12.6 (100% MK-4) Cow’s liver (pan fried) 0.4 (100% MK-4)
Cheddar cheese (U.S.) 10.2 (6% MK-4, 94% other MK) Egg white 0.4 (100% MK-4)
Meat franks 9.8 (100% MK-4) Skim milk 0.0
Chicken breast 8.9 (100% MK-4)

See also

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