| Vitamin K | |||||
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- Why vitamin K is good for you
- Important vitamin K facts
- Groups at risk of vitamin K deficiency
- Symptoms of vitamin K deficiency
- Vitamin K and health
- Vitamin K in foods
- Vitamin K recommended daily intake (RDI)
- Vitamin K works best with
- Overdosage, toxicity and cautions for vitamin K
Vitamin K is needed to make the blood clots that quickly stop the bleeding whenever injury occurs. This fat-soluble vitamin comes in three forms:
- Vitamin K1 or phylloquinone – this form is found in plant foods
- Vitamin K2 or menaquinone – this is the form that friendly bacteria make in the intestines
- Vitamin K3 or menadione – this is the artificial form
All Vitamin K ends up in the liver, where it is used to make some of the substances that make the blood clot.
Vitamin K also has an important role in building bones - it is needed to keep the calcium in the bones and make sure it is getting to the right place.
- No information available
Groups at risk of vitamin K deficiency
As a rule, vitamin K deficiency is rare – almost everyone gets enough from their own bacteria or their food. When adults get Vitamin K deficiency, it is generally because they eat very few green vegetables or because they have been taking oral antibiotics for a long time. Sometimes vitamin K deficiency is caused by liver disease or a problem digesting fat.
Deficient of vitamin K occurs in:
- People who have serious liver disease – cannot use Vitamin K properly and will probably be recommended to have Vitamin K shots
- People iIntestinal disorders – people with Crohn's disease, ulcercative colitis or other gastrointestinal disoders do not digest fats well, so may not absorb enough vitamin K
- Long term users of antibiotics – antibiotics kill all bacteria (good and bad) so they kill the bacteria in the intestine that help make Vitamin K. Eating more foods rich in vitamin K should help
- People who take cholesterol-lowering drugs – these drugs block absorption of vitamin K and other fat-soluble vitamins.
Talk to a medical professional about Vitamin K supplements BEFORE taking them.
Symptoms of vitamin K deficiency
Main signs of deficiency are:
- Blood clots very slowly, bleeding occurs for a long time from small injuries
- Small bruises cause big black-blue marks
- Nose-bleeds
- Blood in the urine
- Intestinal bleeding
- Blood Clotting - blood has a number of different clotting factors – substances that help it form clots to stop bleeding from cuts, bruises and other injuries. Vitamin K is needed to help the liver make prothrombin (factor II), the most important of the clotting factors. Some of the other factors, including factors VII, IX and X, are also made in your liver and also depend on vitamin K. Without clotting factors, blood clots very slowly or not at all, so even a small cut can bleed for a long time and even a minor bang can cause a big bruise
- Osteoporosis - vitamin K is needed to help the bones take calcium and put it in the right place and hold it other. If there is not enough vitamin K, bone cannot be very well formed. In the long run, a shortage of vitamin K can lead to osteoporosis - bones that are brittle and break easily. Researchers believe that once osteoporosis starts, vitamin K may help to slow down the process. This is still being researched
- Vitamin K kills cancer cells - so far, only in test tubes in the laboratory, Vitamin K seems to slow down or kill tumour cells just as well as powerful anti-cancer drugs. Research is continuing in this important area
| FOOD | AMOUNT | Vitamin K (mg) |
|---|---|---|
Turnip greens, raw |
½ cup | 182 |
Cauliflower, raw |
½ cup | 96 |
Beef, liver |
85g | 89 |
Soybean oil |
1 tspn | 76 |
Spinach, raw |
½ cup | 74 |
Broccoli, raw |
½ cup | 58 |
Cabbage, raw |
½ cup | 52 |
Tomato, raw |
1 medium | 28 |
Egg |
1 large | 25 |
Strawberries |
1 cup | 21 |
Milk, skim |
1 cup | 10 |
Wheatgerm |
28g | 10 |
Vitamin K recommended daily intake (RDI)
| RDA | lifestage | age | Amount |
|---|---|---|---|
| INFANTS | 0-6mths 7-12mths |
2.0mcg 2.5mcg |
|
| CHILDREN | 1-3yrs 4-8yrs |
8mcg 12mcg |
|
| CHILDREN | 9-13yrs 14-18yrs |
20mcg 25mcg |
|
| ADULTS | 19-50yrs |
30mcg | |
| SENIORS | 51+yrs | 30mcg | |
| PREGNANT | 30mcg | ||
| LACTATING | 35mcg | ||
| TOLERABLE UPPER LIMIT | none established |
||
| TOXIC LEVELS | essentially non-toxic | ||
The tolerable upper limits should only be taken for short periods and only under medical supervision.
- Dietary fat is necessary for the absorption of this vitamin
Overdosage, toxicity and cautions for vitamin K
Toxicity does not easily occur with normal dietary intake of this vitamin, but can happen if the synthetic compound vitamin K3 is taken. High to toxic uptake in the synthetic form can cause flushing and sweating. Jaundice and anemia may also develop.
Any more than 100mcg in the synthetic form of vitamin K could be toxic and damage the liver. Talk to a medical professional about supplements made with phytonadione, a water-soluble version of Vitamin K1.
CAUTION
- People on blood-thinning drugs such as Coumarin (Coumadin) or Warfarin should NOT take Vitamin K supplements - it will prevent the drug from doing its job!
- People on anti-coagulant drugs should NOT take Vitamin K supplements
People taking any type of medication should talk to a medical professional about Vitamin K supplements BEFORE taking them.
references
- Bell RG, Sadowski JA, Matschiner JT. Mechanism of action of warfarin. Warfarin and metabolism of vitamin K1. Biochem. 1972;11:1959-1961
- Cashman KD. Vitamin K status may be an important determinant of childhood bone health. Nutr Rev. 2005 Aug;63(8):284-9. Review
- Knapen MH, Schurgers LJ, Vermeer C. Vitamin K(2) supplementation improves hip bone geometry and bone strength indices in postmenopausal women. Osteoporos Int. 2007 Feb 8
- Mager DR, McGee PL, Furuya KN, Roberts EA. Prevalence of vitamin K deficiency in children with mild to moderate chronic liver disease. J Pediatr Gastroenterol Nutr. 2006 Jan;42(1):71-6
- Office of Dietary Supplements USA - has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 9 August 2005
- Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing
- Sato y, Honda Y, Hayasida N, Iwamoto J, Kanoko T, Satoh K. Vitamin K deficiency and osteopenia in elderly women with Alzheimer's disease. Arch Phys Med Rehabil. 2005 Mar;86(3):576-81
