Vitamin K is stored in the fat tissue of the body and plays an essential role in helping blood clot properly. A vitamin K deficiency can lead to excessive bleeding or hemorrhaging. Although each brand of multivitamins may contain different types or amounts of vitamins, most multivitamins do contain vitamin K. If you have specific concerns about your intake of vitamin K, consult a doctor.
Is Vitamin K Supplementation Necessary?
Since the bacteria found in the intestines can make vitamin K, vitamin K deficiencies are rare. Vitamin K is also found in many leafy green foods, so people who eat a well-balanced diet also may have a sufficient intake of the vitamin without supplementation. However, it is not dangerous to get too much vitamin K, so the presence of vitamin K in a multivitamin supplement should not cause any adverse effects even if you don't necessarily need it. On the other hand, some people with certain medical conditions are at risk for a vitamin K deficiency. These conditions include liver disease, gallbladder or biliary disease, cystic fibrosis, Crohn's disease, celiac disease, diseases that require the use of blood-thinning medications, continuing hemodialysis and serious burns. If you suffer from any of these conditions, you may need to rely on supplements to maintain appropriate levels of vitamin K.
Recommended Intake of Vitamin K
Healthy individuals can use two recommendations to determine how much vitamin K to take: the daily value amount or the recommended dietary allowance amount. The daily value, established by the U.S. Food and Drug Administration, is a more general guideline. It is applicable to all healthy individuals regardless of gender or age. The daily value amount of vitamin K is 80 mcg per day. The recommended dietary allowance, on the other hand, is the average amount sufficient to meet the needs of healthy people of a certain age group or gender. The recommended daily value of vitamin K is 90 mcg a day for adult females and 120 mcg a day for adult males.
People who are healthy and not at risk for a vitamin K deficiency should generally keep their intake of the vitamin as close to daily value or recommended dietary allowance amounts as possible. However, vitamin K does not have a tolerable upper intake level, so taking large doses of the vitamin is unlikely to cause any dangerous side effects. If you have a medical condition that interferes with your body's ability to make or store vitamin K, talk to your doctor to determine the appropriate dosage for you. The amount found in a multivitamin supplement may not be enough for your condition.
Amount Found in Multivitamins
Most multivitamin supplements contain vitamin K. However, most do not contain even as much as the daily value amount, let alone the recommended dietary allowance amount for adults, according to a Linus Pauling Institute Research Report conducted by Jane Higdon. This is typically not a cause for concern, because the body can produce vitamin K on its own and because the vitamin is so plentiful in the leafy green foods of a healthy diet. However, if you have a poor or restricted diet or have a medical condition that puts you at risk for a deficiency, you may require extra vitamin K supplementation.
Warning
Vitamin K may interact negatively with certain medications. If you would like to begin taking a multivitamin that contains vitamin K, rule out potential interactions first. Medications that may interact negatively to vitamin K include antibiotics, phenytoin, warfarin, orlistat, olestra, cholestyramine, colestipol and colsevelam. In addition, always take your multivitamin supplement as directed on the label. Although it is not dangerous to get too much vitamin K, getting too much of other vitamins or minerals can cause serious side effects. Call a doctor if you experience any unusual reactions after taking a multivitamin supplement.
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