Is Vitamin K The Same Thing As Potassium? Doctors Explain

You've likely heard about the importance of getting your vitamins since childhood. Running through a checklist of ones you need can feel like a trip through the ABCs. Vitamin A from oysters and milk for skin health? Check. B vitamins from whole grains and lean meats for strong muscles? Check. Vitamin C from oranges (of course) for immune health? Check...and so on. However, what about vitamin K?

"Vitamin K is often overlooked compared to popular vitamins like C and D, yet it plays several critical roles in our body," says Dr. Holiday Durham, Ph.D., MS, RD, a registered dietitian with Amway. "Think back to a time you injured yourself and were bleeding. After a bit of time, your injury stopped bleeding. Vitamin K is vital for blood clotting factors and is partially responsible for this injury to stop bleeding and to heal."

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Durham says vitamin K's other "superpowers" include assisting with bone and heart health. Sound good? Of course it does. Vitamin K is found in many foods, and your mind might immediately drift to bananas, thinking vitamin K is code for potassium. Are vitamin K and potassium the same thing? More specifically, are vitamin K2 and potassium the same thing? Registered dietitians have all those answers and more insights on vitamin K, its function, health benefits and the foods that have it.

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What Is Vitamin K?

"Vitamin K is a fat-soluble vitamin that is found in a variety of foods and can be produced in small amounts by the bacteria living in the human gut," says Eliza Whitaker, MS, RDN, a registered dietitian and medical nutrition adviser at Dietitian Insights. "It is...most easily absorbed by the body in the presence of fat but is also stored in adipose tissue and the liver posing a concern for toxicity when supplemented."

It's crucial to our health.

"Vitamin K plays a role in producing proteins found in tissues within the body, including bone, as well as blood clotting by acting as a cofactor," Whitaker says.

It comes in two forms, explains Michelle Routhenstein, MS, RD, CDCES, CDN, the preventive cardiology dietitian at EntirelyNourished.com:

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  • Vitamin K1 (phylloquinone): Found in leafy green vegetables, vitamin K1 assists with heart health and proper blood clotting

  • Vitamin K2 (menaquinone): Vitamin K2 supports bone and heart health. Fermented foods are excellent sources of it.

When we don't get enough vitamin K, Whitaker says a person can experience:

  • Poor bone health

  • Osteoporosis

  • Excessive bleeding

  • Higher risk of cardiovascular disease

Are Vitamin K and Potassium the Same Thing?

No, vitamin K is different from potassium, Dr. Durham says. Therefore, the answer to the question, "Is vitamin K2 potassium?" is also no.

It might help to back up and understand what potassium is.

"Potassium is a mineral and an electrolyte that aids in muscle contraction and blood pressure regulation by counteracting the effects of sodium and fluid balance," Whitaker says. "It may prevent kidney stones and may support bone health."

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Whitaker says foods rich in potassium include:

  • Bananas

  • Potatoes

  • Spinach

  • Lentils

  • Quinoa

  • Dairy products

Dr. Durham says the idea that vitamin K and potassium are the same thing—while untrue—is a common misunderstanding. K is the sign of potassium on the Periodic Table of Elements. However: "Fun fact: Minerals are included, vitamins are not. So, only potassium is represented, not vitamin K," Dr. Durham says.

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Benefits of Vitamin K

1. Bone health

Research suggests that people who get enough vitamin K are less likely to experience broken bones, especially as they age. Older research indicates it improves bone mineral density.

"Vitamin K supports the synthesis of osteocalcin, a protein that binds calcium in bones, enhancing bone mineralization and reducing fracture risk," Dr. Durham says. "This is vital for helping to prevent osteoporosis, especially among aging populations."

2. Heart health

A 2021 Journal of American Heart Association study found that people consuming a diet packed with vitamin K were a third less likely (34%) to develop atherosclerosis (hardening of the arteries) than their peers consuming the lowest amount.

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"Vitamin K may help with reducing the risk of cardiovascular disease by promoting calcium into the bone versus the heart muscle," Routhenstein says.

3. Cognitive health

Vitamin K might help boost cognitive health. For instance, a 2013 study of people over 70 found that those consuming the most vitamin K via plant-based sources showed better verbal memory. Another study from 2022 showed lower risks of dementia in people with higher concentrations of vitamin K2 in their brains.

Dr. Durham says that more research is needed before we can conclusively say vitamin K helps with brain health and functioning.

4. Blood clotting

Vitamin K literally helps stop the bleeding. "Vitamin K plays a crucial role in producing four of the 13 clotting factors found within the body," Whitaker says. "Without enough vitamin K, clotting may be impaired."

5. Insulin sensitivity

People with diabetes can especially benefit from paying attention to vitamin K intake.

"Vitamin K intake may aid in improving insulin sensitivity in those with diabetes," Whitaker says. "More research is needed to better understand this connection."

Still, Whitaker points to a 2020 mini-review in Nutrients that cited promising data that this health benefit may have legs.

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What Foods Have Vitamin K?

Lori Barrett, RDN, of Top Nutrition Coaching, explains that tons of foods are rich in vitamin K. For vitamin K1, she recommends loading up on:

  • Kale

  • Spinach

  • Collard greens

  • Romaine lettuce

  • Green beans

  • Peas

  • Brussels sprouts

  • Broccoli

  • Cabbage

  • Parsley

  • Cilantro

  • Basil.

Barrett says vitamin K2-packed foods include:

  • Natto (fermented soybean product)

  • Sauerkraut

  • Kimichi

  • Tempeh

Do You Need  Vitamin K Supplement?

Probably not. The National Institutes of Health Office of Dietary Supplements recommends males 19 and older get 120 mcg of vitamin K daily, and females (regardless of pregnancy/lactation status) get 90 mcg of vitamin K daily. Dr. Durham says vitamin K deficiency is rare, and most people can get enough through foods.

"Supplementation of vitamin K is generally not required for individuals consuming a balanced diet," Dr. Durham says.

Whitaker says signs you might need more vitamin K in your diet include:

  • Weakening of the bones

  • Osteoporosis

  • Excessive bleeding

  • Sleepiness

  • Bruising easily

  • Jaundice

Importantly, these can be signs of other underlying health conditions. Dr. Durham recommends speaking to your doctor, who can order labwork to check your vitamin levels.

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