A Nutritionist’s Guide To Vitamin K

Eli Brecher Nutritionist

A Nutritionist’s Guide To Vitamin K

Vitamin K is a fat-soluble vitamin, which is a type of vitamin most abundant in high fat foods and is best absorbed into the bloodstream when eaten with fats, similarly to vitamins A, D and E.

In this post I’ll break down:

  • why do we need vitamin K
  • what are the 2 types of vitamin K
  • do you need a vitamin K supplement
  • who is at a higher risk of vitamin K deficiency
  • what foods are good sources of vitamin K

Are you concerned you may not be getting enough nutrients in your diet? If you’re interested in improving your nutrition and your health, head to Consultations to see how I can help you start your journey to the healthiest version of yourself today!

Eli Brecher Nutritionist

Why do we need vitamin K?

Vitamin K is known for its ability to help our blood clot, prevent excessive bleeding and wound healing, but is also needed for strong bones and heart health.

Vitamin K is broken down very quickly in our bodies and excreted in urine or stool, so it rarely reaches toxic levels in the body even with high intakes, as can occur with other fat soluble vitamins. As a result, it is important to consume it regularly in our diets, on most days if not all.

Some research has indicated that vitamin K2 can be used to treat osteoporosis and steroid-induced bone loss, also potentially preventing further fractures in patients. Research has reached conflicting conclusions however, so further trials are needed as most research was conducted in Japan on postmenopausal women so we can’t yet draw conclusions in the UK or on a global scale.

What are the 2 types of vitamin K, and where can we get them?

There are two types of vitamin K in the diet: vitamin K1 and vitamin K2.

Vitamin K1, also known as phylloquinone, is important for blood clotting and is mainly found in plant foods, particularly green leafy vegetables like chard, kale, spinach, Brussel’s sprouts, cabbage, asparagus, lettuce, broccoli, avocado, green beans, prunes, soybeans and kiwi. It makes up about 75-90% of the vitamin K we eat in our diets.

Vitamin K2, also known as menaquinone, is also important for blood clotting, but additionally supports the body’s absorption of calcium. It is found in certain animal foods in small amounts like beef liver, chicken, cheese and egg yolk, as well as fermented foods, particularly natto (a Japanese food made from fermented soybeans), which is the richest dietary source of vitamin K. The body also produces vitamin K2 in the gut from bacteria (gut microbes).

Do you need a vitamin K supplement?

We need about 1 mcg of vitamin K per kilogram of body weight per day, so if you weigh 70kg you would need 70mcg, although it is not typically supplemented unlike other vitamins because deficiencies are rare in healthy adults.

It’s important to note that everyone’s nutritional requirements will be different, which is why I take a personalised approach with all of my 1:1 clients and tailor each nutrition plan to their unique needs and goals.

Who is at a higher risk of vitamin K deficiency?

Deficiencies can be common in newborn infants though, due to poor transfer of vitamin K to the placenta and low amounts in breast milk. Secondary deficiencies can occur in people who do actually consume adequate amounts in their diets, meaning the deficiency occurs for a different reason. For example, if you have a disease that affects absorption in the digestive tract like Crohn’s disease or coeliac disease, cystic fibrosis, chronic pancreatitis or if you drink excessive alcohol (or have liver damage or disease) or are malnourished.

Note: If taking anticoagulants (blood thinning medication), vitamin K intake needs to be kept relatively stable as these drugs work to do the opposite to what vitamin K does, so sudden changes can increase or decrease the anti-blood clotting effect of this medication.






This is just a small insight into the types of things I discuss with my 1:1 clients. If you’re looking to optimise your nutrition, transform your health and elevate your quality of life, please get in contact via Consultations or book a FREE 15-minute call and let’s chat about how I can help.  


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