About Vitamin K
Vitamin K is a fat-soluble vitamin that has a role in blood clotting, bone metabolism, and regulating calcium levels in the body.
Vitamin K produces prothrombin that is a protein and clotting factor. It is important for blood clotting and bone metabolism.
Those taking blood-thinning medications should not start vitamin k without consulting their doctor.
Deficiency of vitamin K is rare but can lead to hemorrhage and excessive bleeding.(1)
Vitamin K1 is obtained from plants and is the main type of dietary vitamin K. Vitamin K2 is a lesser-known source and it occurs in animal-based and fermented foods.
Uses of Vitamin K
Vitamin K1 that is also known as phylloquinone, is found in plants. When it is consumed, bacteria present in the intestine convert it into vitamin K2, which is its storage form. This then gets stored in fatty tissue and the liver.
The body cannot produce prothrombin, a clotting factor necessary for blood clotting and bone metabolism without vitamin K.
Vitamin K deficiency is most likely to occur in newborns with malabsorption problems. It can occur due to short-bowel syndrome, cystic fibrosis, celiac disease, or ulcerative colitis.
Newborns are normally given vitamin K to prevent bleeding in the skull that could be fatal.(2)
The recommended adequate intake of vitamin K for women aged 19 years is 90 microgram a day and for men 120 mcg a day.(1)
Sources of Vitamin K
Vitamin K1 is found to be high in leafy green vegetables such as kale, spinach, asparagus, and Swiss chard. It is also present in vegetable oil and some fruits.
Vitamin K2 is present in meat, dairy products, eggs, and Japanese ‘natto’ that are made from soybeans.
Importance of Vitamin K for the Body
Vitamin K benefits the body in numerous ways, which includes:
Improves Bone Health
There is a correlation between low intake of vitamin K and osteoporosis.
Vitamin K helps in maintaining strong bones and improves bone density.(3) It is also known to decrease the risk of fractures.
Improves Cognitive Health
Good vitamin K levels are linked with improved episodic memory in older adults.(4)
A study done on healthy individuals over 70 years of age with the highest vitamin K1 levels found them having the highest verbal episodic memory performance.
Improves Heart Health
Vitamin K helps in lowering the blood pressure levels thereby preventing mineralization, a process in which minerals build up in the arteries. Preventing this mineral build-up enables the heart to pump blood freely through the body.
Mineralization is a major risk factor for heart disease and it occurs naturally with age.
Vitamin K is also known to lower the risk of stroke.(5)
Risks Associated with Vitamin K
There is no upper limit determined for vitamin K and toxicity is also rare. Toxicity can never result from eating food containing Vitamin K.
Taking vitamin K supplements can cause toxicity. Vitamin K interacts with several medicines including blood thinners, anticonvulsants, antibiotics, cholesterol-lowering drugs, and weight loss drugs.
- Blood thinners are used to prevent the formation of blood clots that may block the blood flow to the brain or heart. They work by decreasing the clotting ability of vitamin K. Consuming supplements can suddenly increase or decrease the vitamin K intake and interfere with the effect of drugs.
- Anticonvulsants, taken during pregnancy and breastfeeding can increase the risk of vitamin K deficiency in the fetus or newborn.
- Cholesterol-lowering medications affect the absorption of fats. Dietary fats are required for absorbing vitamin K. Those taking these medications have a higher risk of vitamin K deficiency.
Anyone taking these medications should consult the healthcare provider about their vitamin K intake.
A balanced diet is the best way to ensure that body is getting its required nutrients in sufficient amounts. Supplements should only be taken when there is a deficiency and under the supervision of a medical professional.