World's Healthiest Foods rich in
vitamin K
vitamin K
FoodCalsDRI/DV
Basic Description
There are few nutrients as closely identified with a specific food source as vitamin K. We list ten foods and spices that contain more than the adult male Adequate Intake (AI) for vitamin K, and each one is a green vegetable. In fact, you'll need to go down to number 17 on our list to find the first food—soybeans—that is not green.Given the rich quantity of green vegetables in the World's Healthiest Foods recipes, you'll get more than enough vitamin K to meet your daily needs with our approach. This is good news because the health benefits associated with diets rich in vitamin K have been expanding in new and unexpected ways.
If you've read about vitamins A, B, C, D, and E, you might feel like we've missed a few as we jump to vitamin K. But there are no vitamins F through J (at least not yet). Vitamin K is named after the German word for blood clotting (koagulation). We'll explain the link as we talk about the role of vitamin K in health support below.
There are two types of vitamin K found in our diets. One type, and by far the more important to human nutrition, is phylloquinone (or vitamin K1). This type is found in plant foods only. The other type is menaquinone (also known as vitamin K2). This type is produced in bacteria, including the type of bacteria found in human and animal intestines. Happily, both types of vitamin K appear to be sufficient to prevent deficiency, although some believe that vitamin K2 may have some unique effects at the far reaches of intake.
Of the World's Healthiest Foods, 21 are excellent sources of vitamin K. Another seven WHFoods are very good sources, and 12 are good sources. Five of the World's Healthiest Herbs and Spices are excellent sources of vitamin K, as well. This list should provide you plenty of choices to ensure a strong vitamin K intake.
Role in Health Support
Blood Clotting
The association between dietary vitamin K and blood clotting is confusing, although this nutrient is very important in management of this critical process. Blood clots are necessary to stop bleeding when our skin gets cut, but inappropriate clotting of blood inside arteries is an important step toward development of coronary artery disease.It turns out that vitamin K plays a role both in the development of blood clots and in the prevention of clotting. These both appear to be true at intake levels that are routinely achieved through usual diets.
Most famously, vitamin K is necessary for proper blood clots to form. The clotting process is exceptionally complex, requiring at least 12 proteins to function before the process is complete. Four of these clotting factors require vitamin K for their activity.
Luckily, we rarely see vitamin K deficiency lead to impairment in the clotting process. We transiently see it in newborns because vitamin K does not efficiently cross the placenta into a fetus, and it takes several weeks to build up dietary stores. We also see it occasionally in those with severe liver or gastrointestinal disease. But vitamin K deficiency basically never causes clotting disorders in healthy adults.
On the other hand, we see a key role for vitamin K in slowing the clotting process. This again occurs via multiple vitamin K-dependent enzyme systems, most importantly one called matrix Gla protein.
It is currently somewhat of an open question how important vitamin K is to the progression of clot formation and heart disease. Researchers have sometimes, but not consistently, been able to correlate low vitamin K intake with increased risk of heart disease.
One problem in interpreting this research, however, is separating out the effect of healthy foods from the nutrients they contain. Even casual readers of this site are probably aware that the same green leafy vegetables that are our richest sources of vitamin K are also among the best sources of many other heart-protecting nutrients.
Researchers have attempted to answer this question by giving vitamin K in pill form at amounts similar to those found in the diet. Over a three-year period, 500 mcg of vitamin K—about the amount found in a serving of mustard greens—was associated with slightly slower progression of hardening of the arteries of the heart.
Given the preliminary and often contradictory nature of this research, we would characterize the association between diets high in vitamin K and protection against coronary artery disease to be plausible, but still unproven.
Bone Health
Vitamin K is necessary for the activation of a protein called osteocalcin. This protein is used in the mineralization of bone, a process by which calcium and other minerals are added to the structural protein matrix.Researchers are only now starting to see the critical ancillary role vitamin K plays in bone metabolism. For example, low levels of vitamin K are emerging as a potential risk factor for osteoporosis, particularly in people with bowel disease. Additionally, researchers have shown that increasing dietary vitamin K intake by 100 mcg per day—roughly doubling the average American adult intake—led to a significant increase in bone density in post-menopausal women over one year.
Perhaps unexpectedly, low intakes of vitamin K have also been correlated in multiple studies with arthritis. Drilling down, researchers have found low activity of vitamin K dependent-proteins inside arthritic joints, establishing a potentially causative relationship.
Note that the same green leafy vegetables that are our best sources of vitamin K are also very good to excellent sources of calcium and magnesium, the two most important minerals for building strong bones.
Summary of Food Sources
Understanding the best food sources of vitamin K is a pretty easy process. You can be pretty confident that any green vegetable contains 10% or more of your Adequate Intake (AI) for vitamin K. If that green vegetable is leafy, you should expect it contains close to 100% of the AI, and could potentially contain several times that much.The best sources of vitamin K are all plant foods. In addition to green vegetable sources, many fruits and legumes contain significant amounts of vitamin K. We see examples of both types of foods—blueberries and soybeans, for instance—that provide up to one-third of the adult male AI. Similarly, a number of non-green vegetables provide up to 20% of the AI.
Surprisingly, some herbs and spices contain nutritionally relevant amounts of vitamin K. For instance, just 2 tablespoons of parsley contain the entire AI for this nutrient. A number of other World's Healthiest Herbs and Spices also contain 5% or more of the AI for vitamin K.
While the bacteria in our intestines do produce some absorbable vitamin K, the amounts are not sufficient to meet our daily needs. So you will always need to derive some vitamin K from your diet.
Understanding how to get enough vitamin K from your diet is almost absurdly easy. If you eat two or three servings of green vegetables per day, you'll probably get your AI or close to it. If you make one of those green vegetables leafy, you'll probably approach the AI with this single serving.
Adding fruits or legumes to your diet will help to add some extra vitamin K, as well. Liberal use of fresh herbs and spices in the way that we do in many of our recipes will also add significant vitamin K.
Nutrient Rating Chart
Introduction to Nutrient Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World's Healthiest Foods that are either an excellent, very good, or good source of vitamin K. Next to each food name, you'll find the serving size we used to calculate the food's nutrient composition, the calories contained in the serving, the amount of vitamin K contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.| World's Healthiest Foods ranked as quality sources of vitamin K | ||||||
|---|---|---|---|---|---|---|
| Food | Serving Size | Cals | Amount (mcg) | DRI/DV (%) | Nutrient Density | World's Healthiest Foods Rating |
| Kale | 1 cup | 36.4 | 1062.10 | 1180.11 | 583.6 | excellent |
| Spinach | 1 cup | 41.4 | 888.48 | 987.20 | 429.2 | excellent |
| Mustard Greens | 1 cup | 36.4 | 829.78 | 921.98 | 455.9 | excellent |
| Collard Greens | 1 cup | 62.7 | 772.54 | 858.38 | 246.4 | excellent |
| Swiss Chard | 1 cup | 35.0 | 572.77 | 636.41 | 327.3 | excellent |
| Turnip Greens | 1 cup | 28.8 | 529.34 | 588.16 | 367.6 | excellent |
| Parsley | 0.50 cup | 10.9 | 498.56 | 553.96 | 911.4 | excellent |
| Broccoli | 1 cup | 54.6 | 220.12 | 244.58 | 80.6 | excellent |
| Brussels Sprouts | 1 cup | 56.2 | 218.87 | 243.19 | 77.9 | excellent |
| Romaine Lettuce | 2 cups | 16.0 | 96.35 | 107.06 | 120.6 | excellent |
| Asparagus | 1 cup | 39.6 | 91.08 | 101.20 | 46.0 | excellent |
| Basil | 0.50 cup | 4.9 | 87.94 | 97.71 | 360.4 | excellent |
| Cabbage | 1 cup | 43.5 | 71.40 | 79.33 | 32.8 | excellent |
| Bok Choy | 1 cup | 20.4 | 57.80 | 64.22 | 56.7 | excellent |
| Celery | 1 cup | 16.2 | 29.59 | 32.88 | 36.6 | excellent |
| Kiwifruit | 1 2 inches | 42.1 | 27.81 | 30.90 | 13.2 | excellent |
| Leeks | 1 cup | 32.2 | 26.42 | 29.36 | 16.4 | excellent |
| Cilantro | 0.50 cup | 1.8 | 24.80 | 27.56 | 269.6 | excellent |
| Sage | 2 tsp | 4.4 | 24.00 | 26.67 | 108.8 | excellent |
| Green Beans | 1 cup | 43.8 | 20.00 | 22.22 | 9.1 | excellent |
| Cauliflower | 1 cup | 28.5 | 17.11 | 19.01 | 12.0 | excellent |
| Cucumber | 1 cup | 15.6 | 17.06 | 18.96 | 21.9 | excellent |
| Tomatoes | 1 cup | 32.4 | 14.22 | 15.80 | 8.8 | excellent |
| Oregano | 2 tsp | 5.3 | 12.43 | 13.81 | 46.9 | excellent |
| Black Pepper | 2 tsp | 14.6 | 9.49 | 10.54 | 13.0 | excellent |
| Green Peas | 1 cup | 115.7 | 35.68 | 39.64 | 6.2 | very good |
| Blueberries | 1 cup | 84.4 | 28.56 | 31.73 | 6.8 | very good |
| Prunes | 0.25 cup | 104.4 | 25.88 | 28.76 | 5.0 | very good |
| Grapes | 1 cup | 104.2 | 22.05 | 24.50 | 4.2 | very good |
| Carrots | 1 cup | 50.0 | 16.10 | 17.89 | 6.4 | very good |
| Summer Squash | 1 cup | 36.0 | 6.30 | 7.00 | 3.5 | very good |
| Cloves | 2 tsp | 11.5 | 5.96 | 6.62 | 10.4 | very good |
| Chili Peppers | 2 tsp | 15.2 | 5.71 | 6.34 | 7.5 | very good |
| Soybeans | 1 cup | 297.6 | 33.02 | 36.69 | 2.2 | good |
| Avocado | 1 cup | 240.0 | 31.50 | 35.00 | 2.6 | good |
| Raspberries | 1 cup | 64.0 | 9.59 | 10.66 | 3.0 | good |
| Winter Squash | 1 cup | 75.8 | 9.02 | 10.02 | 2.4 | good |
| Pear | 1 medium | 101.5 | 7.83 | 8.70 | 1.5 | good |
| Miso | 1 TBS | 34.2 | 5.04 | 5.60 | 2.9 | good |
| Bell Peppers | 1 cup | 28.5 | 4.51 | 5.01 | 3.2 | good |
| Plum | 1 2-1/8 inches | 30.4 | 4.22 | 4.69 | 2.8 | good |
| Cantaloupe | 1 cup | 54.4 | 4.00 | 4.44 | 1.5 | good |
| Cayenne Pepper | 2 tsp | 11.4 | 2.89 | 3.21 | 5.0 | good |
| Eggplant | 1 cup | 34.6 | 2.87 | 3.19 | 1.7 | good |
| Cranberries | 1 cup | 23.0 | 2.55 | 2.83 | 2.2 | good |
| World's Healthiest Foods Rating | Rule |
|---|---|
| excellent | DRI/DV>=75% OR Density>=7.6 AND DRI/DV>=10% |
| very good | DRI/DV>=50% OR Density>=3.4 AND DRI/DV>=5% |
| good | DRI/DV>=25% OR Density>=1.5 AND DRI/DV>=2.5% |
Impact of Cooking, Storage and Processing
Vitamin K is a fairly stable nutrient to most types of processing. Levels go down only slightly with common cooking techniques, and tend to stay stable with storage.Vitamin K in oils, but probably not in vegetables, is reduced by exposure to light. This is one reason, but certainly not the only one, that we recommend storing oils in dark areas and in opaque, sealed containers.
The hydrogenation process that is used to stabilize and solidify liquid fats damages a significant amount of the vitamin K content. This is just one of many reasons why we believe that hydrogenated fats should be avoided.
Risk of Dietary Deficiency
For the most part, we don't see frank vitamin K deficiency symptoms in the United States. In part because of this, we don't know definitively what intake level of vitamin K is associated with problems with blood clotting. Reflecting this, scientists talk more about an Adequate Intake (AI) than a true deficiency.By this AI standard, many age groups fail to meet vitamin K recommendations on average. In particular, adolescents and young adults are prone to sub-optimal dietary vitamin K intake. Also, males tend to be less likely to meet AI goals than females.
This high risk of sub-optimal intake is almost certainly telling us about our poor intake of vegetables in the U.S. For example, the average American male in his 20s only obtains about 80 mcg of vitamin K from his diet, an amount less than that found in a single serving of broccoli.
As described above, it would be very easy to move from this standard American diet marginal intake of vitamin K to a more optimal level. Moving toward an approach that is based on the World's Healthiest Foods would be an easy way to make this shift.
Other Circumstances that Might Contribute to Deficiency
The most common reason to see symptoms of vitamin K deficiency, at least related to blood clotting, is use of medications that impair vitamin K utilization. For people using these medications, the symptoms of vitamin K deficiency are the goal, so you'll want to talk to your doctor about how your diet fits into your treatment program.Because vitamin K is a fat-soluble nutrient, you'll only obtain it from foods that contain fat. For instance, the amount of vitamin K found in a fat-free salad dressing is too low to measure. You don't need much fat—turnip greens contain less than a gram of fat per 100 gram serving, and are quite rich in vitamin K. It is theoretically possible, although we can't find evidence that it is common, to eat a diet low enough in fat to impair vitamin K nutrition.
There are a few disease states that can interfere with vitamin K nutrition or utilization. For instance, any digestive disease that impairs absorption of fat-soluble nutrients may impair vitamin K uptake from foods. End-stage liver disease can also lead to symptoms of vitamin K deficiency.
Relationship with Other Nutrients
Both vitamin A and vitamin E can compete for absorption with vitamin K. To our knowledge, however, this has only been reported with mega-dose supplementation, not with dietary intake. As such, you probably do not need to eat in a certain pattern to protect your vitamin K nutrition.Vitamin K works with the other nutrients important to bone health—calcium, vitamin D, and magnesium—to ensure that your skeleton stays strong. A deficiency of any of these nutrients can lead to problems that cannot be fully undone by focusing on the other nutrients on the list.
Risk of Dietary Toxicity
To our knowledge, there has never been a report of a person developing an adverse reaction to vitamin K who was not on medications that are influenced by this nutrient. Given the strong track record of safety, the National Academy of Sciences did not choose to establish a Tolerable Upper Intake Level (UL) for vitamin K. Further evidence for the safety of dietary vitamin K comes from research studies where doses of vitamin K at 500 times the Adequate Intake (AI) did not lead to observable toxicity.This is good news, as some of the WHFoods recipes contain close to 20 times the adult male AI for vitamin K. This is unique among the nutrients we profile on our website.
Please note that the UL is only meant to describe nutrient intake for healthy adults. There are widely used medications that require vitamin K restriction during treatment. If you are on one of these, you'll need to work with your medical team to ensure proper vitamin K intake.
Disease Checklist
- Blood clotting disorders
- Osteoporosis
- Coronary artery disease
- Cancer
- Liver disease
- Celiac disease
- Crohn's disease
- Ulcerative colitis
- Cystic fibrosis
Public Health Recommendations
In 2001, the Food and Nutrition Board (FNB) of the National Academy of Sciences released a set of Dietary Reference Intakes (DRI) for vitamin K. These included a set of age and gender specific Adequate Intake Levels (AI) that are summarized in the following chart. The FNB chose to establish an AI instead of a Recommended Dietary Allowance because the existing research data are not currently strong enough to determine a truly deficient level of intake. The AIs are as follows:- 0-6 months: 2 mcg
- 6-12 months: 2.5 mcg
- 1-3 years: 30 mcg
- 4-8 years: 55 mcg
- 9-13 years: 60 mcg
- 14-18 years: 75 mcg
- 19+ years, female: 90 mcg
- 19+ years, male: 120 mcg
- Pregnant or lactating women, 14-18 years: 75 mcg
- Pregnant or lactating women, 19+ years: 90 mcg
The Daily Value (DV) for vitamin K is 80 mcg. This is the value that you'll see on food and supplement labels.
References
- Ferland G, Sadowski JA. Vitamin K1 (phylloquinone) content of edible oils: effects of heating and light exposure. J Agric Food Chem 1992;40:1869-73.
- Fisher L, Byrnes E, and Fisher AA. Prevalence of vitamin K and vitamin D deficiency in patients with hepatobiliary and pancreatic disorders. Nutr Res. 2009;29:676-83.
- Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington, DC: National Academy Press; 2001;394-419.
- Kanellakis S, Moschonis G, Tenta R, et al. Changes in parameters of bone metabolism in postmenopausal women following a 12-month intervention period using dairy products enriched with calcium, vitamin D, and phylloquinone (vitamin K1) or menaquinone-7 (vitamin K2): the Postmenopausal Health Study II. Calcif Tissue Int 2012:90:251-62.
- Kuwabara A, Tanaka K, Tsugawa N, et al. High prevalence of vitamin K and D deficiency and decreased BMD in inflammatory bowel disease. Osteoporosis Int 2009;20:935-42.
- Neogi T, Booth SL, Zhang YQ, et al. Low vitamin K status is associated with osteoarthritis in the hand and knee. Arthritis Rheum 2006;54:1255-61.
- Oka H, Akune T, Muraki S, et al. Association of low dietary vitamin K intake with radiographic knee osteoarthritis in the Japanese elderly population: dietary survey in a population-based cohort of the ROAD study. J Orthop Sci 2009:14:687-92.
- Peterson JW, Muzzey KL, Haytowitz D, et al. Phylloquinone (vitamin K1) and dihydrophylloquinone content of fats and oils. J Am Oil Chem Soc 2002;79:641-6.
- Shea MK, Holden RM. Vitamin K status and vascular calcification: evidence from observational and clinical studies. Adv Nutr 2012;3:158-65.
- Shea MK, O'Donnell CJ, Hoffmann U, et al. Vitamin K supplementation and progression of coronary artery calcium in older men and women. Am J Clin Nutr 2009;89:1799-807.
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