7/28/2019 Vitamin K for Vegans

1/2

Table 1. Vitamin K in Plant Foods2

Food Preparation Serving g

Broccoli boiled 1/2 cup 110

Kale shredded,boiled 1/2 cup 531

Spinach boiled 1/2 cup 442

Collards boiled 1/2 cup 418

Romaine lettuce shredded 1 cup 48

Swiss chard boiled 1/2 cup 286

0 Tweet 2 Vegan For Li fe

by Jack Norris, RD &Ginny Messina,

MPH, RDFor Updates: Follow @JackNorrisRD or subscribe to JackNorrisRD.com

Vitamin K

Summary

Vitamin K is needed for proper blood clotting and bone health. Vegans who eat leafy green vegetables with some

added oil on a daily basis should receive more than adequate vitamin K. Even those who do not might obtainenough vitamin K from intestinal bacteria, unless they have had a significant course of antibiotics. Making sureyou get plenty of vitamin K through leafy green vegetables is the best plan.

Vitamin K Requirements and Issues

Vitamin K is a vitamin needed for blood clotting. It also has activity in bones and deficiency can result in bonefractures, especially in old age. The Dietary Reference Intake for vitamin K is 120 g for men and 90 g forwomen. Table 1 shows the vitamin K content of plant foods that are high in vitamin K.

Vitamin K refers to the chemical menadione and any derivatives of it that exhibit anti-hemorrhagic activity inanimals fed a vitamin K-deficient diet. There are two types:

Phylloquinone - found primarily in plant foods; most prevalent in green leafy vegetables. Traditionallycalled vitamin K1. (1)

Menaquinone - found in animal tissues and bacteria. Traditionally called vitamin K2. (1)

Because menaquinone is not found in plant foods,some laypeople have suggested you need to eatanimal products in order to have adequate vitamin Kstatus. The scientific consensus has been that eitherof the two types of vitamin K are adequate, especiallyregarding vitamin K's blood clotting activity. In theUnited States, enteral nutrition products, which areused for people who cannot eat normally and oftenprovide the only nutrition they receive for months oryears, contain phylloquinone for vitamin K (1) andthese patients presumably do fine, with regard toblood clotting, with only phylloquinone in their diet.

Additionally, menaquinone is produced by a numberof different bacteria species that typically live in thedigestive tract of humans (1), and can be absorbed in

the distal part of the small intestine (5). Unlesssomeone has had significant antibiotic therapy, theyshould have plenty of such bacteria providing themwith menaquinone. It is difficult to induce vitamin K deficiency (measured by slow blood clotting) by removingvitamin K from the diet, presumably due to the production of vitamin K by intestinal bacteria (1). However, it ispossible to induce vitamin K deficiency (slow blood clotting) through antibiotic therapy, indicating intestinalbacteria provide a significant amount of vitamin K (1).

One study measuring blood-clotting in vegetarians (3) and one study measuring blood-clotting in vegans (4) didnot show them to have slow blood clotting times. An abnormal rate of blood clotting problems has not beenapparent for children raised vegan from birth; it would be unusual for their diets to be supplemented withmenaquinone.

It, therefore, seems safe to assume that vegans have no need for menaquinone supplementation; especiallywhen it comes to vitamin K and blood clotting. But what about bone health? Again, apparently healthy vegans

Home | Sit e Map

Quick Links

Recommendations

Vitamin B12

Calcium & Vitamin D

Protein

Sports Nutrition

Meal Plans

Vegan Kids

Research on Vegans

Disease Treatment

Soy & Food Allergies

Raw Foodism

Dietetics

Companion Animals

Translations

Like 31 Send

Page 1 of 2Vitamin K

13-Jun-13http://www.veganhealth.org/articles/vitamink

7/28/2019 Vitamin K for Vegans

2/2

are probably getting plenty of menaquinone, if it's even necessary to have in addition to phylloquinone, from gutbacteria.

There is evidence that elderly women can reduce their chance of bone fracture by supplementing with vitamin K,specifically phylloquinone (6). So it appears that phylloquinone is also adequate for bone health and there is noevidence to date that menaquinone is superior. A literature search (May 2010) revealed no studies comparingphylloquinone to menaquinone with regard to bone health.

There is one vegan food that is very high in menaquinone: natto. Natto has 998 mcg of menaquinone per 100 gportion (1).

Fat and Vitamin K Absorpt ion

Vitamin K is a fat-soluble vitamin, and fat can significantly increase its absorption from food (7). Since green leafyvegetables naturally contain very little fat, it is a good idea to add some fat or oil when preparing them.

References

1. Suttie J W. Vitamin K in Health and Disease. CRC P ress, Boca Raton, FL. 2009.

2.USDA National Nutrient Database

3. Mezzano D, Munoz X, Martinez C, Cuevas A, Panes O, Aranda E, Guasch V, Strobel P, Munoz B, Rodriguez S, PereiraJ , Leighton F. Vegetarians and cardiovascular risk factors: hemostasis, inflammatory markers and plasma homocysteine.Thromb Haemost 1999 J un;81(6):913-7.

4. Sanders TA, Roshanai F. Platelet phospholipid fatty acid composition and function in vegans compared withage- and sex-matched omnivore contr ols. Eur J Clin Nutr. 1992 Nov;46(11):823-31. (Same study population as citation25.)

5. Conly J M, Stein K, Worobetz L, Rutledge-Harding S. The contribution o f vitamin K2 (menaquinones) produced bythe intestinal microflora to human nutritional requirements for vitamin K.Am J Gastroenterol. 1994 Jun;89(6):915-23. (Abstract)

6. Stevenson M, Lloyd-Jones M, Papaioannou D.Vitamin K to prevent fractures in older women: sys tematic reviewand economic evaluation. Health Technol Assess. 2009 Sep;13(45):iii-xi, 1-134. Review.

7. Gijsbers BL, J ie KS, Vermeer C. Effect of food composition on vitamin K absorption in human volunteers.Br JNutr. 1996 Aug;76(2):223-9.

Contact | Copyright 2003-2013

VeganHealth.org

Page 2 of 2Vitamin K

13-Jun-13http://www.veganhealth.org/articles/vitamink