Vitamin K: What You Should Know

Sources, Benefits, Forms, Dosage 

What is Vitamin K?

Vitamin K is one of thirteen essential vitamins. Essential vitamins need to be present in the diet because the human body cannot make the nutrients on its own, or in sufficient amounts to sustain normal and healthy bodily functions.1 Vitamin K is considered an essential vitamin due to its many physiological health benefits. Along with being essential, Vitamin K is also fat-soluble, which means unlike water-soluble vitamins, these nutrients are stored in the liver and the fat cells of fatty tissue. Since the four fat-soluble vitamins, Vitamin A, D, E, and K are stored in tissue and not as easily flushed out of the body, there is a risk to develop toxic side effects. However, toxicity only occurs when the vitamin is taken in very high concentrations.

Benefits of Vitamin K – There are many

Vitamin K was discovered in Germany by the Danish physiologist, Henrik Dam whom concluded that a Vitamin K deficiency in chickens caused uncontrollable bleeding.1 Vitamin K, also known as the “clotting” or “koagulation (coagulation) vitamin”, is involved with the production of the protein prothrombin, which plays a critical role in blood clotting to heal the body after a cut and also prevent excessive bleeding from wounds1,2

In addition to benefiting the cardiovascular system and preventing vascular calcification, Vitamin K also supports tooth formation and bone health such as bone density, formation, and repair by producing the protein osteocalcin.3,4,5 Other research shows it even helps to prevent certain diseases, including heart disease, osteoporosis, and certain types of organ cancers such as lung, liver, and even leukemia.3

Forms of Vitamin K – Which is best?

The three types of Vitamin K include phylloquinone or Vitamin K1, menaquinone or Vitamin K2, and menadione or Vitamin K3.1,4 Vitamin K1 is the form found in mostly plant food sources and is poorly absorbed and mostly excreted from the body.1,4 Vitamin K2 is the form produced by the good bacteria in the large intestine and is also found in some food sources.1,4 Vitamin K3 is the synthetic form and is also known to have toxic effects.1,4

The most effective, protective, active, and bioavailable form of Vitamin K is Vitamin K2 in the form MK7, known by the trade name MenaQ7™. Vitamin K2 is most effective because it goes to your blood vessels first, is then delivered to other tissues, and is predominately absorbed in the small intestine. Menaquinone is the form that has the most benefits and is strongly related to the decreased risk of coronary heart disease and arterial calcification.5 The video below explains why Vitamin K2 in this form is so important and superior to other forms.

Sources of Vitamin K – From food and nutrition supplements

Vitamin K1 and K2 are naturally sensitive to heat and light, therefore the nutrient content can be diminished or destroyed when preparing meals.Dietary sources rich in Vitamin K1 include leafy, dark green vegetables such as kale, spinach, Brussels sprouts broccoli, asparagus, and vegetable oil.1,3,4 Food sources of Vitamin K2 include butter, cheese, egg yolks, meat, and fermented soybean products.1,3,4 Vitamin K2 is also produced inside the human body from the bacteria in the intestines.2 Vitamin K3 is not found naturally in dietary sources as this type is the synthetic form of the nutrient.

All forms of Vitamin K can be found in supplements, but vitamin K2 in a nutrition supplement is the best and most efficient option. When consuming fat-soluble vitamins it is best to accompany these nutrients with a dietary fat for optimal absorption.1 The presence of bile from the liver and pancreatic enzymes also facilitates absorption of fat-soluble vitamins like Vitamin K.4

Recommended daily dose of Vitamin K – What physicians advise

The recommended daily dose for nutrients is unique to a person’s age, gender, and other personal factors. A recommended dietary allowance (RDA) has not been established, but adequate intake (AI) levels have been set for Vitamin K. The adequate intake amounts in Table 1 are a reference for nutritional adequacy in seemingly healthy individuals.4 The adequate intake of vitamin K for adults is 90 mcg (micrograms) for women and 120 mcg for men.1

Adequate Intake (AI) of Vitamin K
Infants (0 – 12 months) 2-2.5 mcg/day
Children (1 -8 years) 30-55 mcg/day
Adolescents (9 – 18 years) 60-75 mcg/day
Adults (19+ years) 90-120 mcg/day
Pregnant and Lactating Women 75-90 mcg

Table 1:  Daily Vitamin K Adequate Intake (AI) for Healthy Individuals5

Certain populations may need to be more mindful when evaluating their Vitamin K needs. Individuals using antibiotics long-term may need to increase their levels because antibiotics kill the Vitamin K producing bacteria found in the intestines.1 Those taking blood-thinning medications, such as Warfarin or Coumadin®, need to control Vitamin K intake by restricting certain foods that contain high levels of Vitamin K or consuming consistent amounts to prevent nutrient fluctuations.1,4 Vitamin K can interfere with anti-coagulants which can result in dangerous and slower blood clots.1,4 Note that people who use blood thinners for a long period of time are placed at an increased risk to develop bone fractures specifically in the vertebrae and ribs due to the lack of Vitamin K in the diet.With any particular medication or health condition it is always best to consult with your primary healthcare provider before taking the Healthycell® products or any nutrition supplement.

Vitamin K toxicity – Very rare

No tolerable upper intake level (UL) or maximum daily consumption level that may cause adverse effects has been established for Vitamin K because of the lack of data, and toxicity is extremely rare, especially in adults.4,6 Vitamin K1 and K2 in both dietary and supplemental form have not produced any known toxic effects, but Vitamin K3 is a potentially toxic form.8 In the past, the synthetic type (menadione) was given in injection form to premature infants to treat Vitamin K deficiency, and it did result in toxicity and jaundice in some cases.4,6 Consequently, menadione is not used anymore to treat deficiency, and instead phylloquinone, Vitamin K1 is used as needed to treat infant deficiency. Vitamin K is the only fat-soluble vitamin out of the four that does not have an upper intake level known to cause toxic side effects.

Vitamin K deficiency, symptoms and people at risk

Vitamin K deficiency is rare in adults, but newborn infants are more susceptible as their intestines lack the bacteria that produce Vitamin K, and there are low levels of Vitamin K in breast milk.1 Newborns who are severely Vitamin K deficient develop the disease Vitamin K deficiency bleeding (VKDB), which causes uncontrollable internal bleeding.1 To prevent VKDB the American Academy of Pediatrics suggests an injection of 0.5-1 mg of vitamin K1 (phylloquinone) at birth.4

Adults with vitamin K deficiency experience symptoms of bruising easily, unmanageable bleeding, and hemorrhaging.2,4 Specifically, adult women who consume inadequate levels of vitamin K and have overall poor nutrition are more susceptible to hip fracture and low bone mineral density (BMD).9 Those who are at risk for vitamin K deficiency include infants, people using antibiotics long-term, people using anti-coagulant medications, people with liver disease, and people with poor nutritional status or malabsorption conditions such as inflammatory bowl syndrome, celiac disease, cystic fibrosis, ulcerative colitis, and short bowel syndrome.4,6

Vitamin K in Healthycell® Pro – Only the best form

The type of Vitamin K really matters to your health. Healthycell® uses only the best form of Vitamin K, which is Vitamin K2 (menaquinone) from natural chickpea extract in the form MK7, known by the trade name MenaQ7™.  The dosage of Vitamin K2 in Healthycell® and Healthycell® Pro is 40 mcg in the morning formula and 40 mcg in the evening formula, for a daily dose of 80 mcg, satisfying 100% of the Daily Value (%DV). Nutrition supplement labeling and food labeling guidelines use Reference Daily Intake (RDI) as the standard for dosage.


1.  McGuire, Michelle, PhD, and Kathy Beerman A., PhD. “Chapter 11 Fat-

Soluble Vitamins.” Nutritional Sciences: From Fundamentals to Food. 2nd ed.

Australia: Thomson/Wadsworth, 2007. 504-507. Print.

2.  Wax, Emily, RD, David Zieve, MD, and Isla Ogilvie, PhD. “Vitamin K.”MedlinePlus

Medical Encyclopedia. U.S. National Library of Medicine, 2 Feb. 2014. Web. 13 Oct. 2016.

3.  Balch, Phyllis A., CNC. Prescription for Nutritional Healing. 4th ed. New York: Avery, Print.

4.  “Vitamin K — Health Professional Fact Sheet.” National Institues of Health. U.S.

National Library of Medicine, 31 Aug. 2016. Web. 12 Oct. 2016.

5.  Geleijnse, Johanna M., Cees Vermeer, Diederick E. Grobbee, Leon J. Schurgers, Marjo H.

Knapen, Irene M. Van Der Meer, Albert Hofman, and Jacqueline C.M. Witteman. “Dietary Intake

of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study1.

” The Journal of Nutrition 134 (2004): 3100-105. The Journal of Nutrition. The American Society for

Nutritional Sciences, 1 Nov. 2004. Web. 15 May 2017.

6.  Brasaemle, Dawn, PhD. “Vitamin K Lecture.” Rutgers University – Vitamin K. New

Brunswick. 2015. Lecture

7.  PJ, Caraballo, Heit JA, Atkinson EJ, Silverstein, MD, and Melton LJ. “Long-term Use

of Oral Anticoagulants and the Risk of Fracture.” Arch Intern Med. (1999): 1750-756. Web.

8.  Higdon, Jane, PhD, Victoria J. Drak, PhD, Barbara Delage, PhD, and Sarah L. Booth, PhD.

“Vitamin K.” Linus Pauling Institute. Oregon State, 03 Jan. 2017. Web. 11 May 2017.

9.  Booth, Sarah L., Kerry E. Broe, David R. Gagnon, Katherine L. Tucker, Marian T. Hannan,

Robert R. McLean, Bess Dawson-Hughes, Peter WF Wilson, and And L Adrienne Cupples.

“Vitamin K Intake and Bone Mineral Density in Women and Men1,2,3,4.” The American Journal

of Clinical Nutrition 77 (2003): 512-16. Web. 11 May 2017.