Foods that are high in vitamin K include meat, strawberries, eggs, soybeans and other types of beans, according to WebMD. Vegetables such as broccoli, spinach and asparagus are also excellent sources of vitamin K.
Vitamin K is actually a group of compounds, notes WebMD. Vitamin K1 and vitamin K2 are the most essential of the compounds. Vitamin K1 is prevalent in vegetables and leafy greens, and vitamin K2, which is synthesized by bacteria, is found in eggs, cheese and meat. In the United States, vitamin K1 is the main type of vitamin K supplement that is readily available.
Adults are rarely deficient in vitamin K, states WebMD. However, people who are more likely to have a vitamin K deficiency include those who consume substantial amounts of alcohol, are malnourished, take drugs that prevent vitamin K from being absorbed properly or have a disease related to absorption in the digestive tract.
Although side effects are rare when taking appropriate amounts of vitamin K supplements, vitamin K supplements should not be taken unless directed by a doctor, according to WebMD. Some types of drugs, such as blood thinners, aspirin or antibiotics, may interact with vitamin K. Drugs for conditions such as high cholesterol, cancer or seizure may also interfere with the effects of vitamin K supplements.