Do vegans need vitamin K supplements?

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

Vegans who follow a well-balanced diet get high amounts of vitamin K1 from food. But, they may benefit from a vitamin K2 supplement.

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.

It may decrease the risk of osteoporosis, fractures, and heart disease. Also, vitamin K may help you maintain a healthy body weight, as it may improve insulin sensitivity.

Actually, there are two types of vitamin K: vitamin K1 and K2. Both types are important for our health.

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).

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

Vegan 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, carrots, and broccoli.

Do vegans get any vitamin K2 from food?

Although, vitamin K1 is naturally present in many foods, there aren’t common plant-based foods containing vitamin K2.

The only common dietary sources of vitamin K2 are some types of cheese, some meats, and eggs (2).

Moreover, fermented foods are great sources of vitamin K2. Actually, bacteria can synthesize vitamin K2. Actually, the richest food in vitamin K2 is vegan! It’s called “natto”. It’s a traditional Japanese meal. Natto is fermented soybeans. 100g of natto provides about 1,000 mcg of vitamin K2!

Vitamin K2 in natto seems to be a key reason for particularly low hip fracture risk in Japanese women (3)!

These extremely high doses are considered pretty safe. In fact, there isn’t an upper safe dose of vitamin K for healthy people.

Another vegan food rich in vitamin K2 is tempeh. Tempeh is also fermented soybeans. But, the concentration of vitamin K2 in tempeh is inconsistent. It highly depends on the production method.

Last, but not least, the good gut bacteria in the body produce a significant amount of vitamin K2. This dose can partially satisfy our daily needs of vitamin K2.

Thus, although vegans get particularly high doses of vitamin K1 from food, they are unlikely to get any vitamin K2. So, a dietary supplement containing vitamin K2 may be beneficial.

There are supplements containing vitamin K2 along with vitamin D. Vegans are in high risk of being deficient in vitamin D as well. There aren’t many vegan foods rich in vitamin D.

You’ll find a wide variety of dietary supplements with vitamin D and K2 on Amazon.

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/