What is Vitamin K:
Vitamin K is a fat-soluble vitamin. https://lpi.oregonstate.edu/mic/vitamins/vitamin-K Vitamin K helps to make various proteins that are needed for blood clotting (coagulations) and the building of bones. Prothrombin is a protein that depends on vitamin K-dependent that is directly involved with blood clotting. Osteocalcin is another protein that requires vitamin K to produce healthy bone tissue. Because vitamin K storage is limited, the body recycles vitamin K in order to reuse it multiple times. Vitamin K is the essential cofactor (partner) for the proteins that are also involved in bone metabolism, prevention of vessel mineralization, and regulation of various functions of the cell and then of course Blood clotting.
Vitamin K is found throughout the body including the liver, brain, heart, pancreas, and bone. It is broken down very quickly and excreted in urine or stool. https://www.hsph.harvard.edu/nutritionsource/vitamin-k/
Look deeper into Vitamin k and health:
-Blood clotting: Vitamin K helps to make four of the 13 proteins needed for blood clotting which helps stops wounds from continuously bleeding so they can heal. WARNING- People who are prescribed anticoagulants (also called blood thinners) to prevent blood clots from forming in the heart, lung, or legs are often informed about vitamin K. Because of its blood clotting action, vitamin K has the potential to counteract the effects of blood thinning medications.
-Bone health- Vitamin K is involved with the production of proteins in bone, including osteocalcin, which is needed to prevent the weakening of bones. Some studies have shown that higher vitamin K intakes are associated with a lower incidence of hip fractures and low bone density. Also, low blood levels of vitamin K have been linked with low bone density.
- heart disease-A few studies have researched the role of vitamin K for heart health. Vitamin K is involved with the production of matrix Gla proteins (MGP), which help to prevent calcification or hardening of heart arteries, a contributor to heart disease. Because research in this area is very limited, additional studies are needed before a specific amount of vitamin K beyond the standard recommendation is proposed for this condition. https://www.hsph.harvard.edu/nutritionsource/vitamin-k/
WHERE IS VITAMIN K FOUND:
Vitamin K is actually a group of compounds. The most important of these compounds appears to be vitamin K1 and vitamin K2. This essential micronutrient isnt just found in vegetables. It can also be found in certain types of fruit, meat, dairy and fermented foods and is even produced inside your own body by your good gut bacteria.
K1- Vitamin K1 is the most common source that is present primarily in plant foods like leafy green vegetables like spinach, kale, broccoli and cabbage, collard and turnip greens, Brussels sprouts, lettuces
Soybean and canola oil, salad dressings made with soybean or canola oil
Fortified meal replacement shakes
K1 this form is best known for its role in promoting the blood coagulation process.
K2-is found in animal products and fermented foods. Foods high in this vitamin include meat, dairy, eggs and natto (is a traditional Japanese dish composed of fermented soybeans). It is also produced by the beneficial bacteria in your gut microbiome. This form plays an exclusive role in reducing arterial calcification. It also shares functions related to bone, brain, and gut health with vitamin K1.
K3- Vitamin K3 is a synthetic, artificially produced form of vitamin K that doesnt occur naturally. This is unlike vitamin K1 and K2. Though vitamin K3 isnt legally sold in supplement form for humans due to safety concerns, its commonly used in poultry and pig feed, as well as commercial pet foods for dogs and cats. https://www.healthline.com/nutrition/vitamin-k3-menadione#what-it-is Research from the 1980s and 1990s has demonstrated that vitamin K3 is harmful to humans.
These studies have linked vitamin K3 to liver damage and the destruction of oxygen-carrying red blood cells. So, only the K1 and K2 forms of vitamin K are available as dietary supplements and prescriptions. Even though there are harmful effects of vitamin K3 in humans, the vitamin hasnt demonstrated harm to livestock or pets when added to feed in regulated doses.
How much do we need of vitamin K:
This essential vitamin is found primarily in green vegetables, fruits, fermented foods and animal products, which makes it easy to meet your needs through a healthy and well-balanced diet.
There is no RDA for vitamin K. Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA. For adults 19 years and older the AI is 120 mcg for male and 90 mcg for females. I have put a chart on my web site for AI for all age groups. If you are focusing on eating a nutrient rich diet, it is easy to meet your needs for vitamin K.
Table 1: Adequate Intakes (AIs) for Vitamin K 
Age Male Female Pregnancy Lactation
Birth to 6 months 2.0 mcg 2.0 mcg
712 months 2.5 mcg 2.5 mcg
13 years 30 mcg 30 mcg
48 years 55 mcg 55 mcg
913 years 60 mcg 60 mcg
1418 years 75 mcg 75 mcg 75 mcg 75 mcg
19+ years 120 mcg 90 mcg 90 mcg 90 mcg
Here are a few of the top vitamin K sources: I will give the complete list on my website.
Natto, 3 ounces (as MK-7) 850mcg 708 DV
Kale ½ cup cooked: 531 micrograms (over 100 percent DV)
Spinach ½ cup cooked: 445 micrograms (over 100 percent DV)
Turnip greens ½ cup cooked: 265 micrograms (over 100 percent DV)
Dandelion greens ½ cup raw: 214 micrograms (over 100 percent DV)
Mustard greens ½ cup cooked: 210 micrograms (over 100 percent DV)
Swiss chard ½ cup raw: 150 micrograms (over 100 percent DV)
Brussels sprouts ½ cup cooked: 109 micrograms (91 percent DV)
Spring onions (scallions) ½ cup raw: 103 micrograms (86 percent DV)
Cabbage ½ cup cooked: 81.5 micrograms (68 percent DV)
Beef liver 1 slice 72 micrograms (60 percent DV)
Kiwi 1 cup 71 micrograms (59 percent DV)
Chicken breast 3 ounces cooked 51 micrograms (43 percent DV)
Broccoli ½ cup raw: 46 micrograms (38 percent DV)
Avocado 1 cup 31.5 micrograms (26 percent DV)
Blackberries 1 cup 29 micrograms (24 percent DV)
Blueberries 1 cup 29 micrograms (24 percent DV)
prunes 1 ounce 17 micrograms (14 percent DV)
Soft cheese 1 ounce 17 micrograms (14 percent DV)
Kidney beans 1 cup 15 micrograms (13 percent DV)
Pine nuts 1 ounce 15 micrograms (13 percent DV)
Pomegranate 1/2 cup 14 micrograms (12 percent DV)
Cashews 1 ounce 9.5 micrograms (8 percent DV)
Ground beef 3 ounces cooked 8 micrograms (7 percent DV)
Grass-fed butter 1 tablespoon 3 micrograms (2 percent DV)
*Ultra-processed foods and refined sugars, on the other hand, are foods low in vitamin K. If these nutrient-poor foods make up a large part of your diet, it could mean you may not be getting enough of this key vitamin.
Signs of Deficiency-
Vitamin K deficiency in adults is rare, but may occur in people taking medications that block vitamin K metabolism such as antibiotics, or in those with conditions that cause malabsorption of food and nutrients.
While vitamin K deficiencies are uncommon, you may be at higher risk if you:
Have a disease that affects absorption in the digestive tract, such as Crohn's disease or active celiac disease
Take drugs that interfere with vitamin K absorption
Are severely malnourished
Drink alcohol heavily
In these cases, a health care provider might suggest vitamin K supplements
Health Risks from Excessive Vitamin K https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/
From the NIH website it states scientists have not been able to establish a tolerable upper intake level for vitamin K. Further studies are needed. In its report, they state that no adverse effects associated with vitamin K consumption from food or supplements have been reported in humans or animals.
Antibiotic medicines may destroy vitamin-K-producing bacteria in the gut, thereby potentially decreasing vitamin K levels. This can happen if you take the medicine for more than a few weeks. People who have a poor appetite while using long-term antibiotics may be at greater risk for a deficiency, and may benefit from a vitamin K supplement.
Because vitamin K is fat-soluble, it is best to eat vitamin K foods with some fat to improve absorption. So, drizzle some olive oil or add diced avocado to your favorite leafy green salad!