Vitamin K is crucial in the body for its part in blood clotting and prevention of prolonged bleeding. It is a fat-soluble vitamin and is a group of two compounds. Vitamin K1- phylloquinone, which is the main type of Vitamin K usually is found in plant sources, and vitamin K2 menaquinone, some of which is produced naturally in the intestine, the lesser significant source is majorly found in some animal sources and fermented foods. Vitamin K1 is the majorly available source of food supplement. Several researches show that, it also is beneficial in bone health, although the conclusions are still conflicting.

Functions

• Although the deficiency seems to be rare, in some cases it delays the clotting time which leads to haemorrhages and excess bleeding.
• New born infants are at major risk of vitamin K deficiency, because of the inefficiency of the liver to use the vitamin K completely. Low transfer of vitamin K through umbilical cord, Low levels of vitamin K in breast milk and new born infants don’t naturally produce vitamin K2 in the body. A standard vitamin K injection is given in new born infants to avoid excess bleeding in brain due to low vitamin K levels.
• Vitamin K1 is converted by the microbes present in the large intestine to Vitamin K2 i.e. this vitamin K2 is absorbed in small intestine and stored in liver and cells of fatty tissues.
• Prothrombin, a protein and the clotting factor which is essential in blood clotting and bone metabolism is produced in the presence of vitamin K in the body. Without Vitamin K our body is less likely to produce Prothrombin.
• Vitamin K deficiency is mostly seen in people with difficulties in food absorption due to celiac disease, short-bowel syndrome, ulcerative colitis etc.
• Those who use blood thinners like warfarin, coumadin should not consume excess vitamin K without checking with their doctor, as they counter act.

The recommended dietary intake of vitamin K depends on the age and gender of the person. Children require 6-11mg/day as per the age while adults require 15-19mg/day.

Benefits

Bone metabolism

Vitamin K acts as a co factor in a process of the formation of some residues in proteins, they act as determining marker for bone health in diagnostics. Several studies found that vitamin K plays a role in bone health and also decreases the risk of fractures. However, more research is needed to prove the benefits of vitamin K in relation to bone health and osteoporosis.  
Increased vitamin levels helped in cognitive health like improved memory stance and also slow ageing. 

Heart health
Mineralization is a process that occurs naturally with age and has the tendency to increase blood pressure. This in turn increases the risk of heart disease. Studies shows that adding enough vitamin K to your diet helps in preventing this process and keeps the heart healthy, by lowering the risk of stroke.
Some of the researches prove that increased levels of vitamin K helps in cognitive health by improving memory in adults.

Symptoms of deficiency
The primary symptom of deficiency is excessive bleeding. Bleeding can also be evidently seen in the places other than wounds or injuries. Some of the notable signs are:

• Easy and frequent bruises.
• Dark black tar like stool with blood.
• Bleeds in mucous membrane that is lining inside the body.
• Small blood clots underneath nails.
• Sources of vitamin K

These are some of the best ways to get vitamin K in the body.

• Green leafy vegetables like spinach, turnips, kale, mustard greens, parsley, lettuce, greens of beets.
• Vegetable like broccoli, Brussel sprouts, cabbage, cauliflower, green beans, avocado, green peas.
• Lentils like soya beans, sprouted green gram, red kidney beans, dried beans.
• Nuts like cashews, hazel nuts, pine nuts, pecans, walnuts
• Prunes, kiwi, pomegranate, dried figs, grapes, blueberries, strawberries
• Fish, liver, meat, eggs, chicken, cheese
• Other smaller amounts of vitamin K is seen in cereals.
• Some of the amount of vitamin K is also produced in large intestine.
• Since it is a fat-soluble vitamin, they are best absorbed in the presence of fat.

References:
https://www.webmd.com/vitamins-and-supplements/supplement-guide-vitamin-k#2
 https://www.webmd.com/vitamins-and-supplements/supplement-guide-vitamin-k#1
https://www.medicalnewstoday.com/articles/219867.php
https://www.ncbi.nlm.nih.gov/pubmed/23850343#maincontent
http://umm.edu/health/medical/altmed/supplement/vitamin-k