There are three forms of Vitamin K, but the most common form found in our diets is K1, or phylloquinone. Phylloquinone is synthesized by plants.
Vitamin K2, or menaquinone, is formed by natural bacteria in the intestines and can also be found in certain foods like cheeses and fermented soybean products.
Vitamin K3, or menadione, is a synthetic form of the vitamin.
Vitamin K is naturally produced by the bacteria in the intestines, vitamin K plays an essential role in normal blood clotting and helps promote bone health.
Good food sources of vitamin K are green vegetables such as turnip greens, spinach, cauliflower, cabbage and broccoli.
Without sufficient amounts of vitamin K, hemorrhaging can occur. Deficiencies may appear in infants, or in people who take anticoagulants or antibiotic drugs. Newborn babies lack the intestinal bacteria to produce vitamin K and need a supplement for the first week.
People on anticoagulant drugs (blood thinners) may become deficient in vitamin K, but should not change their vitamin K intake without consulting a doctor because the effectiveness of the drug may be affected.
People taking antibiotics may lack vitamin K temporarily because intestinal bacteria are sometimes killed as a result of long-term use of antibiotics. Also, people with chronic diarrhea may have problems absorbing sufficient amounts of vitamin K through the intestine and should consult their physician to determine if supplementation is necessary.