Vitamin K: Comprehensive Nutrient Guide

Unlock the secrets of Vitamin K and its role in blood clotting, bone health, and more with this comprehensive nutrient guide.

Vitamin k

Vitamin K, a fat-soluble vitamin, plays a crucial role in many bodily functions. Despite its importance, it often goes unnoticed in discussions about essential nutrients. This nutrient guide aims to shed light on this vital vitamin, its types, sources, benefits, and potential side effects.

The Types of Vitamin K

There are two naturally occurring forms of Vitamin K: Vitamin K1 and Vitamin K2. Both forms have unique characteristics and functions within the body.

Vitamin K1 (Phylloquinone)

Vitamin K1, also known as phylloquinone, is primarily found in green leafy vegetables. It is the most common form of Vitamin K in the diet. The body uses Vitamin K1 for blood clotting, a vital process that prevents excessive bleeding during injuries.

Vitamin K2 (Menaquinone)

Vitamin K2, or menaquinone, is primarily found in fermented foods and certain types of meat. The bacteria in the gut also produce it. Vitamin K2 is essential for bone health and heart health, as it helps to regulate calcium in the body.

Sources of Vitamin K

Knowing the sources of Vitamin K can help ensure adequate intake of this essential nutrient. Both Vitamin K1 and K2 can be obtained from various food sources.

Sources of Vitamin K1

Green leafy vegetables are the richest sources of Vitamin K1. These include spinach, kale, broccoli, and Brussels sprouts. Other sources include vegetable oils and certain fruits, such as kiwi and avocado.

Sources of Vitamin K2

Vitamin K2 is labeled as MK-n, where "n" is any number from 4-7. Vitamin K2 is primarily found in fermented foods like natto, a traditional Japanese food made from fermented soybeans. It is also present in certain types of cheese, such as Gouda and Brie, and in meats like chicken and beef liver.

Managing Vitamin K Intake

A balanced intake of Vitamin K can be achieved through various dietary sources.

  • Aim for a Mix of K1 and K2: Consume green vegetables for K1 and include sources of K2 like natto, organ meats, and fermented foods, and aim for 100-200 micrograms daily.
  • Supplementation: Consider supplements that provide a mix of MK-4 and MK-7, especially for those with dietary restrictions or specific health conditions.
  • Carnivores: MK-4 is the primary form of an animal-based diet. Add fermented foods and organ meats to diversify the forms of vitamin K.
  • Vegans: K1 is the source of green plants. Adding natto to obtain K2 and should consider supplementing with MK-4.

Supplementation Considerations

When taking supplements that exceed 500 micrograms per day of Vitamin K (not including the Vitamin K naturally present in your diet), it's best to counterbalance every extra 500 micrograms with 3000 International Units (IU) of Vitamin A, 900 IU of Vitamin D, and 5 IU of Vitamin E.

Supplement: Thorne MK-4

Benefits of Vitamin K

Vitamin K offers numerous health benefits, from promoting blood clotting to supporting bone health. It also supports healthy blood sugar, optimal sex hormones, and exercise performance and protects against cancer.

Role in Blood Clotting

Vitamin K is essential for the synthesis of certain proteins that promote blood clotting. Without adequate Vitamin K, the body cannot form clots effectively, leading to excessive bleeding.

Supports Bone Health

Vitamin K2 plays a crucial role in maintaining bone health. It helps to regulate calcium in the body, ensuring that it is deposited in the bones and teeth where it is needed rather than in the arteries and soft tissues.

Heart Health

By regulating calcium deposition, Vitamin K2 can also support heart health. It helps to prevent calcification of the arteries, a risk factor for heart disease.

Blood Super and Hormones

Vitamin K plays a role in maintaining healthy blood sugar levels and optimal sex hormone function.

Kidney Health

Individuals suffering from chronic kidney disease require a minimum of 480 micrograms of Vitamin K2 daily.  They may benefit from a higher dosage, ranging from 3 to 4 milligrams daily, although this higher intake has not yet been thoroughly researched. It's important to note that these studies have exclusively focused on the MK-7 form of Vitamin K2.

Potential Side Effects of Vitamin K

While Vitamin K is generally safe for most people, excessive intake can lead to certain side effects.

Interactions with Medications

Vitamin K can interact with certain medications, such as blood thinners. People taking these medications should monitor their Vitamin K intake and consult their healthcare provider before making any significant changes to their diet.

Risk of Clotting

While Vitamin K is essential for blood clotting, excessive intake can potentially lead to excessive clotting, which can increase the risk of certain health conditions, such as deep vein thrombosis.


Vitamin K is an essential nutrient that plays a crucial role in blood clotting, bone health, and heart health. By understanding the types, sources, benefits, and potential side effects of Vitamin K, individuals can make informed decisions about their diet and health.