Too much vitamin K can be harmful for people with certain medical conditions, including those who take blood thinners to prevent clotting. In some people, an excess of vitamin K also can cause hormonal problems and jaundice. The Food and Drug Administration's recommended dietary allowance for vitamin K is 90 micrograms for women and 120 micrograms for men daily.
Vitamin K protects the heart by helping with blood clotting, and it builds strong bones. People taking blood thinners such as Coumadin should avoid high doses of vitamin K because it can counteract the medication's effects. Those with high blood pressure and heart conditions should consult with their doctor about how much vitamin K they can eat in their diet.
A variety of fresh and prepared foods contain various levels of vitamin K, including pie crust, coleslaw, some fruit, candy, nuts and other products. If you need to watch your vitamin K intake, make a list of the foods that are rich in the nutrient. Even if you are on blood thinners, you still will want to eat some foods with vitamin K to stay within the FDA's recommended daily allowance.
Vegetables and Fruits
The foods with the highest vitamin K content are green, leafy vegetables such as kale, collard greens, spinach and turnip greens. Other foods high in vitamin K are broccoli, Brussels sprouts, lettuce, parsley, asparagus, cabbage, okra, green beans, cucumbers and peas. Vegetables such as artichokes, cauliflower, tomatoes, carrots, peppers, potatoes and alfalfa sprouts contain moderate to low levels. Fruits with a lot of vitamin K are blueberries, kiwi, blackberries and certain varieties of grapes. Plums, raspberries, pears, mangoes, papayas and peaches fall into the moderate-to-low category.
Chicken, turkey, lamb and beef have moderate to low levels of vitamin K. Mung beans and soya beans are high in vitamin K, whereas other types of beans fall in the moderate-to-low range.
Prepared Foods, Pasta, Grains and Desserts
Prepared foods with high levels of vitamin K include cookie-type pie crusts, pickles, and some cereals. Those with moderate vitamin K levels are miso, frozen French fries, and margarine. Pasta products with high amounts of vitamin K include noodles and other pastas made with greens such as spinach. Baked goods and desserts that are moderate to low in vitamin K are muffins, eclairs with custard, pies, doughnuts and candy.
Determining the Amount of Vitamin K in Foods
The U.S. Department of Agriculture has a long list of foods and their vitamin K content. Another source is PTINR's vitamin K registry, where you can research food items online or print out the list. You also can look up foods to find whether they are high, medium or low in vitamin C.