How much vitamin K per day? Why vitamin K is good for you?

Green smoothie with vitamin K rich foods.
Leafy greens on smoothie to boost your RDI of vitamin K.

How much vitamin K per day do we need? What foods are rich in vitamin K? Why is vitamin K important for the human body?

Why vitamin K is good for you?

Vitamin K is present in the liver and other body tissues, like the brain, heart, pancreas, and bone.

For instance, Brussel sprouts that are rich in vitamin K can help against osteoporosis.

Actually there are two types of vitamin K. The first is K1 (phylloquinone) and the second is K2 (a series of menaquinones).

Both types of vitamin K are important for our health.

We can’t detect many amounts of vitamin K circulate in the blood. Vitamin K is rapidly metabolized.

Our bodies retain only about 40% of the vitamin K we consume from foods.

The rest 20% is excreted in the urine and the other 40% in the feces. This rapid metabolism is the reason why vitamin K has low blood levels and tissue stores.

Although vitamin K is a fat-soluble vitamin, it can’t be storer easily. Other fat-soluble vitamins can be stored more easily.

How much vitamin K per day?

According to the American Food and Nutrition Board, the recommended daily intake of vitamin K is 120mcg for men and 90mcg for women (1). Analytically:

AgeMaleFemalePregnancyLactation
Birth to 6 months2.0 mcg2.0 mcg  
7–12 months2.5 mcg2.5 mcg  
1–3 years30 mcg30 mcg  
4–8 years55 mcg55 mcg  
9–13 years60 mcg60 mcg  
14–18 years75 mcg75 mcg75 mcg75 mcg
19+ years120 mcg90 mcg90 mcg90 mcg

Why vitamin K1 is good for you?

Vitamin K1 is mostly known for regulating blood clotting.

Moreover, vitamin K1 may help to prevent liver cancer.

Also, may help to prevent vascular calcifications, especially in patients on warfarin (6).

In a 3-year, double-blind, placebo-controlled trial, vitamin K1 (along with vitamin D) significantly delayed the deterioration of arterial elasticity in 181 postmenopausal women. This was not found with vitamin D alone (7).

Furthermore, vitamin K1 may help improve insulin sensitivity. In a 3-year randomized, double-blind, controlled trial of 355 patients, vitamin K1 significantly improved insulin sensitivity in men with diabetes (8).

Additionally, vitamin K1 has been shown to reduce fractures. A recent meta-analysis has shown that vitamin K1 (45 mg/day) significantly reduced hip (77% reduction) vertebral (60% reduction) and all non-vertebral fractures (9).

Foods rich in vitamin K1

The main source of vitamin K1 is leafy green vegetables.

The best sources of vitamin K1 are collard greens, turnip greens, spinach, kale, and broccoli.

In a whole food plant-based diet you won’t have vitamin K1 deficiency. So many foods contain vitamin K.

The list of foods rich in vitamin K here.

Why vitamin K2 is good for you?

Vitamin K2 is important for human health.

Vitamin K2 is good for the heart

Most noteworthy, vitamin K2 is associated with the inhibition of arterial calcification and arterial stiffening (2).

An adequate intake of vitamin K2 has been shown to lower the risk of vascular damage.

Vitamin K2 activates matrix GLA protein, which inhibits the deposits of calcium on the walls of arteries.

Healthiest vegan breakfast with vitamin K rich spinach.
Vitamin K rich breakfast.

Also, vitamin K2 can optimize calcium use in the body, preventing any potential negative health impacts associated with increased calcium intake.

Vitamin K2 promotes arterial flexibility by preventing the accumulation of arterial calcium.

Some recent scientific evidence suggests that high consumption of calcium can raise the risk of heart disease. Also, high doses of calcium can be connected to the deposit of calcium in blood vessel walls and soft tissues (2).

Vitamin K2 can protect our heart from this calcium overdose.

Have you considered replacing cow’s milk, with other alternatives? 20 reasons why you should do it here.

Vitamin K2 is good for the bones

Some studies have shown that increased consumption of vitamin K2 can lead to increased bone formation and bone mineral density. Furthermore, vitamin K2 can lead to a lower risk of hip fracture (2,3).

Foods rich in vitamin K2

Unfortunately, vitamin K2 can’t be consumed in large quantities, even in a healthy well-balanced plant-based diet.

The main sources of vitamin K2 are some types of cheese, some meats, and eggs (2). Not exactly a plant-based diet.

Vitamin K2 is produced by bacteria.

It can be found in tiny amounts in some fermented foods and animal products. There are only a few plant-based sources.

Plant-based sources of vitamin K2

The plant-based food that is mostly researched, about its high concentration in vitamin K2 is natto.

Natto is a traditional Japanese fermented soy food, that contains high amounts of vitamin K2.

Scientists investigated the connection between the consumption of natto and decreased risk of hip fracture. They found a relatively lower fracture risk in Japanese women (3).

Other sources of vitamin K2

Another plant-based source of vitamin K2 is tempeh. Tempeh is a fermented soy food.

The fermentation of soy foods can result in the formation of vitamin K2. The downside is that the presence of vitamin K2 is inconsistent. It depends on the production method.

Another study showed that vitamin K2 can be made by human intestinal flora (4). Additionally, gut bacteria can convert vitamin K1 into vitamin K2.

That was examined in a 2002 study, in which, when breastfeeding mothers were supplemented with vitamin K1, vitamin K2 was produced (5).

Remember…The human body can produce vitamin K2.

Deficiency of vitamin K on a vegan diet

Vitamin K deficiency can occur during the first few weeks of infancy due to low vitamin K content of breast milk. Women should consume at least 90mcg of vitamin K daily, through pregnancy and lactation.  

Significant vitamin K deficiency in adults is very rare. It’s usually limited to people taking drugs that interfere with vitamin K metabolism (1).

In conclusion

Vitamin K:

  • promotes bone health
  • can lead to a lower risk of hip fracture
  • optimizes calcium use
  • can lower the risk of vascular damage
  • regulates blood clotting
  • may improve insulin sensitivity
  • is present in leafy vegetables.
  • shouldn’t concern you if you follow a whole food plant-based diet.

Sources

  1. https://ods.od.nih.gov/factsheets/vitaminK-HealthProfessional/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566462/
  3. https://www.ncbi.nlm.nih.gov/pubmed/11369171
  4. https://www.ncbi.nlm.nih.gov/pubmed/8198105
  5. https://www.ncbi.nlm.nih.gov/pubmed/12064330
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4600246/
  7. https://www.ncbi.nlm.nih.gov/pubmed/14961167
  8. https://www.ncbi.nlm.nih.gov/pubmed/18697901/
  9. https://www.ncbi.nlm.nih.gov/pubmed/16801507/