Vitamin K is a group of fat-soluble vitamin compounds called naphthoquinones. These include vitamins K1, K2 and K3. The natural form of vitamin K is vitamin K1, (phylloquinone), which is a phytonadione. It is most commonly found in plants such as leafy green vegetables, and is the primary source of vitamin K that humans obtain through foods.

Another form, Vitamin K2, (menaquinone), is found in fermented foods and animal products.

Health Benefits of Vitamin K

Vitamin K is a group of fat-soluble vitamins that play several important roles in the body, primarily related to the response to injury, blood clotting, bone health, bone metabolism, cardiovascular health, cognitive function and cancer prevention. Ensuring an adequate intake of vitamin K through a balanced diet rich in green leafy vegetables, fermented foods, and other vitamin K sources is important for overall health and well-being.

Here are some of the effects of vitamin K on the body:

Blood clotting: Vitamin K is essential for the synthesis of certain proteins that help regulate blood clotting. These proteins are involved in the coagulation cascade, which is the process by which blood clots form to stop bleeding when a blood vessel is injured. Without adequate vitamin K, blood clotting would be impaired, leading to an increased risk of excessive bleeding.

Bone health: Vitamin K is also important for bone health, as it helps regulate the mineralization of bone tissue. Vitamin K activates osteocalcin, a protein that binds calcium to the bone matrix, helping to maintain bone density and strength. Vitamin K assists in the distribution of the mineral calcium throughout the body, further contributing to bone health. It contributes to the reduction of bone loss thereby decreasing the risk of bone fractures. Studies have suggested that adequate vitamin K intake may help reduce the risk of osteoporosis and fractures, particularly in postmenopausal women.

Cardiovascular health: Some research has suggested that vitamin K may play a role in cardiovascular health by helping to prevent the calcification of arteries. By activating matrix Gla protein (MGP), vitamin K helps inhibit the deposition of calcium in arterial walls, which may help reduce the risk of atherosclerosis (hardening of the arteries) and cardiovascular disease.

Cognitive function: Emerging research suggests that vitamin K may also play a role in cognitive function and brain health. Some studies have found an association between low vitamin K levels and cognitive decline, although more research is needed to fully understand the relationship between vitamin K and brain health.

Cancer prevention: There is some evidence to suggest that vitamin K may have anti-cancer properties, although more research is needed to confirm this potential benefit. Some studies have found that higher intakes of vitamin K, particularly vitamin K2, may be associated with a reduced risk of certain types of cancer, including prostate cancer.

Other Health Benefits: There are those who advocate the use of vitamin K supplementation for certain cancers, spider veins, morning sickness and other conditions, but these are unproven.

Vitamin K Deficiencies

Most experts agree that unless a person has a condition that limits the absorption of dietary vitamins, there is little need for supplements. Unfortunately, these conditions do exist, in which case a supplement could be considered.

The following conditions may cause Vitamin K deficiency: chronic malnutrition due to Crohn’s disease or colitis, alcohol dependency and those taking drugs that interfere with vitamin K absorption, those who take high doses of aspirin and quinine, those who take antacids as they may be at risk of not absorbing enough vitamin K from their diets.

Vitamin K shots for Babies

In some countries, such as the UK, the parents of all babies are offered a shot of Vitamin K for their baby soon after birth. This is because newborns are born with low levels of vitamin K, and their intestines do not yet produce enough vitamin K-producing bacteria to meet their needs. Additionally, breast milk, which is the recommended source of nutrition for infants, contains only small amounts of vitamin K.

The vitamin K shot, also known as phytonadione, is a synthetic form of vitamin K1 that helps prevent vitamin K deficiency bleeding (VKDB), also known as hemorrhagic disease of the newborn. VKDB is a rare but potentially life-threatening condition characterized by bleeding into various organs, including the brain, which can lead to serious complications or death.

By administering a vitamin K shot shortly after birth, healthcare providers can ensure that newborns have adequate levels of vitamin K to support normal blood clotting and reduce the risk of VKDB.

Vitamin K in Children

Parents should ensure their children’s health by making sure they eat a balanced diet that is rich in greens. If you suspect that your child is not getting enough vitamin K, your physician might recommend an injection of vitamin K. This might be called upon to prevent various bleeding disorders in infants. However in most cases you can get enough vitamin K from the diet.

Foods Rich in Vitamin K

There are some foods that are particularly rich in vitamin K. These include: leafy greens such as; kale, Swiss chard, parsley, spinach, broccoli, asparagus, cauliflower, Brussel sprouts, liver, soybean oil, wheat bran, strawberries and eggs.

Vitamin in K2 form can be obtained by ingesting fermented dairy, including; yogurt, cheeses, fermented soy including miso and natto.

Other food sources of vitamin K are meats, which are synthesized by bacteria.

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Vitamin K Notes / Side Effects

Vitamin K is generally considered safe when consumed in amounts that do not exceed the recommended dietary intake. Vitamin K toxicity from dietary sources is rare, as the body typically regulates vitamin K levels effectively.

However, excessive intake of vitamin K supplements can potentially lead to adverse effects, particularly in individuals with certain medical conditions or those taking specific medications.

Here are some considerations regarding potential side effects of vitamin K:

Allergic reactions: Some individuals may experience allergic reactions to vitamin K supplements, particularly if they are allergic to any of the ingredients used in the supplement formulation. Allergic reactions can range from mild skin rashes to more severe symptoms such as difficulty breathing. If you experience any signs of an allergic reaction after taking a vitamin K supplement, seek medical attention immediately.

Interactions with medications: Vitamin K can interact with certain medications, particularly anticoagulants (blood thinners) such as warfarin. Since vitamin K plays a role in blood clotting, high doses of vitamin K supplements can interfere with the effectiveness of anticoagulant medications, potentially increasing the risk of blood clots or bleeding. If you are taking anticoagulant medication, it’s important to speak with your healthcare provider before taking vitamin K supplements to ensure safe and appropriate use.

Interactions with blood thinning herbs: Vitamin K can interfere with the effectiveness of anticoagulant medications and potentially certain herbs that have blood-thinning properties. Vitamin K is essential for blood clotting, so it can counteract the effects of anticoagulants by promoting blood clot formation. The following herbs are amongst those that contain compounds with blood-thinning properties, so when these herbs are taken with high doses of vitamin K, the effects will counteract each other and reduce the effectiveness of the anticoagulant therapy; Alfalfa, Ginseng, Anise, celery, Chamomile, Horse Chestnut and Red Clover.

Gastrointestinal issues: In some cases, high doses of vitamin K supplements may cause gastrointestinal symptoms such as nausea, vomiting, diarrhea, or stomach cramps. These symptoms are more likely to occur with excessive intake of vitamin K supplements rather than through dietary sources.

Interaction with certain medical conditions: Individuals with certain medical conditions, such as liver disease or gallbladder disease, may need to exercise caution when taking vitamin K supplements. In these cases, vitamin K supplementation may be contraindicated or require close monitoring by a healthcare provider.

Hemolytic anemia (rare): In very rare cases, high doses of vitamin K supplements may cause hemolytic anemia, a condition characterized by the destruction of red blood cells. This adverse reaction is extremely uncommon and is more likely to occur in individuals with a genetic predisposition or underlying medical condition.

If you have any concerns about the safety of taking vitamin K supplements, consult with your healthcare provider for personalized guidance and recommendations.