Vitamin K is an essential vitamin that the body uses to help the blood clot, create healthy bones, and keep the heart strong. A vitamin K deficiency is serious and can lead to a range of health issues. Even getting less than the recommended dosage over a prolonged period may be bad for a person’s overall health, and could lead to problems such as: low bone mineral density, heart disease, osteoporosis, tooth decay, easy bleeding or difficulty clotting blood, certain types of cancer, vascular calcification, and cognitive impairment.
Recommended Intake
The recommended intake of vitamin K is at least 90 micrograms (mcg) a day for women and at least 120 mcg a day for men. Most people can easily achieve these levels by adding the foods below to a balanced, healthful diet.
Types of Vitamin K
There are two types of vitamin K: vitamin K-1 and vitamin K-2. Vitamin K-1 is present in a higher number of foods and is particularly abundant in green vegetables and the oils of some plants. Vitamin K-2 is found in just a few animal sources and some fermented vegetables, such as natto, a fermented soybean dish.
While most dietary guidelines do not currently differentiate between vitamins K-1 and K-2, it may be best to provide the body with sources of both types. Most people eating a balanced diet rich in whole fruits and vegetables are sure to get enough vitamin K in their diets, especially vitamin K-1. One of the simplest ways to include additional vitamin K-1 into the diet is to eat dark, leafy greens.
Vitamin K-2 may be more challenging to incorporate into a healthful diet, as it is found most commonly in meat and animal products. Healthful gut bacteria produce some vitamin K-2, but the best way to ensure the body gets enough is by eating it. Common sources of vitamin K-2 include meat, liver, and some dairy products. While meat and dairy eaters can often find sources that contain vitamin K-2, vegetarians and vegans may be limited. A Japanese fermented soybean dish called natto is an excellent source of vitamin K-2. Getting both vitamin K-1 and K-2 in the diet is essential for ideal overall health, and some foods make it easy to hit the daily-recommended values.
Read also: Plant-Based K2 Guide
Foods High in Vitamin K-1
Listed below are some of the foods that contain high levels of vitamin K-1. It is important to note that the levels of vitamin K are measured per 100 grams (g) of food. Although some of the herbs, such as basil and thyme, seem to contain very high amounts of vitamin K, it is unlikely that a person would use such large quantities while cooking.
- Cooked spinach - 540.7 mcg
- Cooked kale - 418.5 mcg
- Cooked mustard greens - 592.7 mcg
- Cooked collard greens - 623.2 mcg
- Cooked beet greens - 484 mcg
- Raw swiss chard - 830 mcg
- Raw dandelion greens - 778.4 mcg
- Cooked turnip greens - 518.9 mcg
- Broccoli - 141.1 mcg
- Cooked cabbage - 108.7 mcg
- Raw arugula - 108.6 mcg
- Dried basil - 1714.5 mcg
- Dried sage - 1714.5 mcg
- Dried thyme - 1714.5 mcg
- Dried marjoram - 621.7 mcg
- Dried oregano - 621.7 mcg
- Fresh parsley - 1640 mcg
- Dried coriander leaf - 1359.5 mcg
- Endives - 231 mcg
- Chives - 212.7 mcg
- Raw cress - 541.9 mcg
- Cooked brussel sprouts - 193.5 mcg
- Red leaf lettuce - 140.3 mcg
- Green leaf lettuce - 126.3 mcg
- Soybean oil - 183.9 mcg
- Mayonnaise - 163 mcg
- Margarine - 101.3 mcg
Foods High in Vitamin K-2
100 g of the following foods contain high levels of vitamin K-2.
- Natto - 939 mcg
- Goose liver - 369 mcg
- Beef liver - 106 mcg
- Turkey sausage - 36.6 mcg
- Chicken meat - 35.7 mcg
- Turkey frankfurter - 31.2 mcg
- Salami - 28 mcg
- Pepperoni - 41.7 mcg
- Soft cheese - 506 mcg
- Blue cheese - 440 mcg
- Hard cheese - 282 mcg
- Full-fat milk - 38.1 mcg
- Bacon - 35 mcg
Health Benefits of Vitamin K
Adding more vitamin K-rich foods to the diet may have some protective benefits. One study noted that people who had a higher intake of vitamin K-2 had a reduced risk of cancer. Vitamin K-2 also appears to improve bone quality, which could lead to a reduction in broken bones. As a 2017 review noted, bone density is not always affected by vitamin K-2 intake, but people who took vitamin supplements that included calcium, vitamin D, and vitamin K-2 were 25 percent less likely to have a bone fracture in their lifetime.
The same review also noted the importance of vitamin K for keeping insulin levels balanced. Participants who took vitamin K-1 supplements showed improved insulin resistance in one study. Another study indicated that an increased intake of vitamin K-1 led to a decreased risk of developing diabetes. While consuming more vitamin K may help improve glycemic control in some people, it should not replace any medications for diabetes.
Vitamin K may play also play a role in preventing Alzheimer’s disease, as older adults taking vitamin K were found to have improved cognitive abilities and less difficulty recalling memories.
Read also: Nutrient Deficiencies on Carnivore
Maximizing Vitamin K Absorption
To help your body fully absorb vitamin K, it's beneficial to consume a bit of fat along with vitamin K-rich foods. Vitamin K is a fat-soluble vitamin, dissolving in fat to be stored in your body, rather than leaving it immediately as waste. Eating a bit of healthy fat with or before eating foods rich with vitamin K will help your body reap the most benefits.
Foods high in unsaturated fats are healthy choices to eat just before vitamin K-rich foods. Try pairing your vitamin K sources of healthy fats with:
- Avocados.
- Heart-healthy oils, like extra virgin olive oil or avocado oil.
- Nuts and nut butters.
- Whole or 2% milk or yogurt.
- Olives.
- Seeds.
For example, you could toss a spinach and kale salad (vitamin K) with olive oil dressing and avocado (fats). Or mix fresh blueberries (vitamin K) in your plain yogurt (fat). Or munch on a charcuterie board of dry roasted cashews (vitamin K) and olives (fat).
You don’t have to eat a lot of fat to get the vitamin-absorbing effects. Just a bit will do. The goal should be to fill up more on vitamin-rich foods than on fats, even if they’re healthier fats.
This same fat-plus-vitamins approach is best for other fat-soluble vitamins as well. That includes vitamin A, vitamin D and vitamin E. Some vitamins, like vitamin C and B vitamins, are water-soluble, so drink a glass of water when taking those vitamins or eating foods rich in them.
Read also: Boosting Vitamin D on a Vegetarian Diet
Vitamin K and Warfarin
On the other hand, people taking anticoagulants or the blood-thinning medications should be cautious about consuming too much vitamin K. People taking these medications should speak to a doctor about their vitamin K levels. For people taking medication, knowing which foods contain high sources of vitamin K is the best way to avoid them.
Some foods you eat affect the way warfarin works in your body. Try and keep eating what you normally do. It is most important to eat a healthy, consistent, and balanced diet. Certain foods and dietary supplements have vitamin K. Vitamin K works against warfarin. If you eat more vitamin K, it can lower your INR. This puts you at a higher risk for making a blood clot. If you eat less vitamin K, it can raise your INR. This puts you at a higher risk for bleeding.
It is okay to eat foods that have vitamin K, but make sure it is not in large amounts. It is important to eat the same amount of foods that have vitamin K each week. Check with your care team before making any big changes in your diet. Contact your care team if there are sudden changes in your diet due to illness.
The most common foods with high vitamin K are green leafy vegetables, such as kale, collard or mustard greens, broccoli, spinach, cabbage, and romaine or dark green lettuce. Other foods that could affect warfarin are beef liver or other animal liver products. Vitamin K can also be found in some nutrition supplements, such as Boost®, Ensure®, and Slim Fast®, certain multiple vitamins and Viactiv® calcium chews, and tobacco, such as cigarettes and chewing tobacco. Talk with your care team if you have questions about vitamin K.