While it is extremely difficult for someone to experience an overdose of vitamin K, it is not unheard of. Children are especially susceptible to issues caused by a vitamin K overdose. Symptoms to watch for include nausea, vomiting, jaundice, skin rash, diarrhea, and anemia.
Vitamin K is a fat soluble vitamin responsible for the production of blood clotting factor. It is produced by bacteria in the small intestine, and found in green leafy vegetables, meat, and dairy products. The kind found in food is known as vitamin K1, or phylloquinone. Vitamin K2, a group of compounds known as menaquinones, is produced in the body. The third kind, vitamin K3 or menadione, is a synthetic version and most commonly associated with vitamin K overdose.
Pregnant women are discouraged from taking vitamin K supplements. They have been shown to cause jaundice in the newborn. Children taking vitamin K supplements should be carefully monitored for symptoms of overdose. Vitamin K3, which is the most likely to be toxic, is not recommended for children. Infants receiving unfortified formula should take supplements containing vitamin K.
Vitamin K is available in supplements for people who do not get enough in their diet, or those with blood clotting disorders. Over-the-counter supplements contain vitamin K1, since it is less likely to be associated with vitamin K overdose. A vitamin K1 injection is routinely given to newborns in the United States. A newborn's intestines do not contain bacteria, and very little vitamin K is carried in breast milk. Vitamin K overdose in a newborn may cause hemolytic anemia, a serious disorder caused by the premature rupture of red blood cells.
There can be other problems with vitamin K besides an overdose. Allergic reaction is possible, and more likely with vitamin K3. People with certain diseases or conditions should consult a health care provider before taking vitamin K. Patients with liver disease may suffer adverse reactions, as will people with glucose-6-phosphate dehydrogenase deficiency. Those with intestinal issues, such as irritable bowel disease, may not be able to fully absorb oral vitamin K, so an injected form is preferred.
Patients taking warfarin or other blood thinners should not take vitamin K supplements because it counteracts their effects. Those taking blood thinners should also maintain a consistent level of dietary vitamin K consumption. Vitamin K is sometimes given to patients who have taken too many blood thinners. Other drugs may interact with vitamin K, so patients should consult a health care provider before taking supplements.
