By LOUISE CARR, Associate Editor and Featured Columnist
You need vitamin K for effective blood clotting but did you know that vitamin K reacts badly with certain drugs including aspirin?
Babies are routinely given vitamin K shots when born but research shows this could be dangerous. Vitamin K may also cause side effects like difficulty breathing and liver problems. Vitamin K is good for the blood, but is it dangerous? Can you overdose on vitamin K?
Vitamin K is not one but three similar substances. Vitamin K1 is found in plants and food sources, K2 is produced by your intestines, and K3 is a synthetic form of vitamin K that is injected or given in supplement form to people who need it. Vitamin K is a fat soluble vitamin. Do you get enough Vitamin K from the foods you eat? Are there any side effects associated with taking too much Vitamin K? vitamin.
How Much Vitamin K Do You Need?
Vitamin K is an essential nutrient but you only need a tiny amount in order to meet minimum requirements.
The National Academy of Sciences (2000) says women over the age of 19 should have 90 micrograms a day, while men over 19 should get 120 micrograms.
Babies up to the age of 12 months need between 2 and 2.5 micrograms, while children need up to 75 micrograms by the time they are 18.
Consider this - 1,000 micrograms is equivalent to 1mg so you don't have to do much in order to meet these requirements.
Vitamin K plays a big part in blood clotting and is used to reverse the effects of blood thinning medications when they are given in too great a quantity. Vitamin K is also used to treat newborns that have blood clotting problems, and to treat bleeding in adults. In addition, vitamin K may be useful for preventing osteoporosis, and for applying to the skin to lessen the effects of bruises, stretch marks, and burns.
Where Do You Get Vitamin K?
Eating a single serving of kale or turnip greens gives you 10 times the recommended daily requirement of vitamin K1.
Other rich sources of vitamin K1 include cabbage, broccoli, spinach and lettuce, as well as whole wheat, oats, green peas, asparagus, chard, celery, leeks, cauliflower, tomatoes and oregano.
But one form of Vitamin K--Vitamin K2 ---cannot easily be obtained from food. You can't ordinarily get Vitamin K2 from food, but the mechanism for converting it is built into your body.
You get vitamin K2 from bacteria in your intestines. Usually your body makes sufficient amounts but taking antibiotics for long periods of time may make you deficient in vitamin K2.
Also, sometimes pregnant and post-menopausal women are deficient in vitamin K2, as are infants born to women taking anticonvulsants.
At the recommended doses vitamin K is safe, and there are no reported toxic levels for the nutrient. However, as with any supplement, when you take vitamin K there is a chance that it will react badly in your body. Documented side effects from taking vitamin K may include sweating and flushing, a tight feeling in your chest, difficulty breathing, irritability and a decreased appetite, muscle stiffness, and swelling. In rare cases you may experience dizziness, low blood pressure, and a fast or a weak heartbeat. As vitamin K supplements are usually injected, there may be swelling and pain at the site of the injection.
Vitamin K directly counters the effects of warfarin so you should not take vitamin K supplements if you are taking warfarin, according to experts including those at Copenhagen Municipal Hospital, Denmark in a 1991 study.
According to these researchers, even dietary vitamin K can be a problem and "should be regarded as an important environmental factor contributing to unwanted disturbances in warfarin-induced anticoagulation."
You also have to be careful to common medications such as aspirin. Aspirin can increase the risk of bleeding when you are taking vitamin K supplements. (Read more about aspirin overdose symptoms.)
Consult your doctor if you are taking aspirin for heart reasons as you may be able to continue taking it, with supervision.
Newborns and Vitamin K
The practice of giving newborns vitamin K injections to decrease the risk of bleeding problems is controversial because certain studies, including a 1990 report from the Royal Hospital for Sick Children, St Michael's Hill, Bristol, UK, claim the procedure increases the risk of cancer.
However, other studies have looked at over one million people and have failed to find a direct link between newborn vitamin K supplementation and cancer.
For example, a 1993 study from the National Board of Health, Stockholm, Sweden looked at 1,384,424 full term infants and couldn't find an association between vitamin K injections and childhood cancer.
Is Vitamin K Safe in Pregnancy?
There is no conclusive data on the safety of vitamin K supplementation during pregnancy so you should only take vitamin K if you need it. Experts don't know whether the vitamin passes into breast milk and causes any issues with a nursing infant - consult your doctor before you take it when you are breast feeding.
In any case, it is better to get your dose of vitamin K the natural way by increasing your intake of leafy vegetables and other sources of the nutrient.
Be Careful With Vitamin K When You Have Liver or Kidney Disease
High doses of vitamin K can make blood clotting problems worse in with liver disease. And too much vitamin K is bad when you are receiving dialysis for kidney disease.
Getting enough vitamin K --- except for Vitamin K2 --- from your diet is normally not difficult, which is why people who are not deficient in vitamin K are not generally advised to take high-dose supplements especially if they have an existing medical condition concerning the blood.
However, some experts suggest that as we understand the role of vitamin K better, it would be beneficial to raise the recommended daily limit for the nutrient. (Read more about the unusual health benefits of Vitamin K.)
Should We Take More Vitamin K?
Experts debated whether we could be getting greater amounts of vitamin K without danger and in 2001 the National Institute of Medicine Food and Nutrition Board raised their recommended levels of vitamin K slightly, but shied away from making bigger increases. Not enough scientific evidence is available, they said, to ensure taking larger amounts of vitamin K is completely safe.
If you have symptoms of a vitamin K deficiency - including excessive or abnormal bleeding like heavy periods or frequent nosebleeds, or blood in the urine or stool - get checked out by your doctor before taking vitamin K supplements. The symptoms of vitamin K deficiency are the same as the symptoms of other serious conditions.
However old you are, and whether you are a man or a woman, it can do no harm to increase your intake of vitamin K through eating more spinach, green leafy vegetables, whole grains, kale, and chard. You get the benefits of the nutrient with hardly any of vitamin K's potential risks to health.