Babies up to 6 months old often have vitamin K deficiency because their bodies contain very little vitamin K at birth, their intestinal bacteria are as yet unable to produce it, and they don't receive enough of it from breast milk, reports the Centers for Disease Control and Prevention. Although vitamin K deficiency is rare in adults, they may get it through heavy alcohol consumption, malnutrition, or diseases or medications that interfere with absorption of the vitamin, explains WebMD.
Vitamin K enables bodies to stop bleeding by forming blood clots, according to the Centers for Disease Control and Prevention. Because babies are often vitamin K-deficient at birth, they may bleed internally into their intestines or brain, causing brain damage or death. Doctors alleviate this condition, known as vitamin K deficiency bleeding, or VKDB, by administering a one-time vitamin K shot to babies within a few hours of birth. Babies are at greater risk for VKDB if they have liver disease, cystic fibrosis, celiac disease or diarrhea. Babies normally display no symptoms of VKDB before their lives are threatened, but occasionally they may show signs such as paleness, bleeding from the umbilical cord or nose, bruising, or bloody stool.
Adults should only take vitamin K supplements when their health care providers advise them, cautions WebMD. People normally get plenty of vitamin K from the foods they eat, especially meat, eggs, beans, strawberries and green vegetables. Although some people take vitamin K supplements for morning sickness, cancer and other disorders, research has not proven the effectiveness of such remedies.