Foods with Vitamin KAfter years of being told that Iceberg lettuce is nutritionally worthless, most of us would be in for a shock to learn that the humble (and usually limpid) lettuce is one of nature's healthiest foods. Iceberg lettuce is just one of a number of important foods with vitamin K. There are a lot of reasons you should care about eating foods containing vitamin K. The K in vitamin K is short for the German word "Koagulation." The body uses vitamin K to change the amino acid glutamic acid into a form that "hooks" calcium ions and strings proteins together so blood can clot. If you don't get enough vitamin K in your diet, or if your liver is damaged so that it can't process vitamin K and make clotting factors, you run the risk of uncontrollable bleeding. Foods with vitamin K are extremely important for your body's healthy responses to scratches, scrapes, cuts, and more serious injuries. In fact, the only thing vitamin K does in your body is to participate in the use of glutamic acid. But that one amino acid is very important. Vitamin K does more than help your blood to clot. Vitamin K makes the protein that moves calcium into your bones. If you don't get enough foods with vitamin K, eating a lot of foods with calcium won't do you any good. Vitamin K also makes a "matrix protein" that ensures that calcium goes into your bones and not into your cartilage. Foods with vitamin K keep you from breaking bones, but they also keep your joints from getting stiff. A peculiarly named compound called Gas6 is a vitamin K-dependent protein that was discovered identified in 1993. It has been found throughout the nervous system, as well in the heart, lungs, stomach, cartilage, and kidneys. Its exact function is not known, but researchers believe that this byproduct of foods with vitamin K keeps these tissues young and responsive to hormones. Vitamin K also helps prevent many of the diseases of aging. If you want to avoid a broken hip, make sure you get your foods with vitamin K. The famous Nurses Health Study, which followed the health of 72,000 nurses for much of the twentieth century, found that women who got the most vitamin K in foods had a 30% lower risk of hip fracture than women who got the least. The equally famous Framingham Heart Study found that vitamin K is important for bone health in men, too. In this study, men and women who got the most foods with vitamin K had a 35% lower risk of broken hip than the men and women who got the least vitamin K - even though their bones weren't measurably denser than those of people who were vitamin K-deficient. The added flexibility around the joint that may be afforded by consuming foods with vitamin K prevented the falls that caused the fractures in the first place. While vitamin K helps put calcium in your bones, it helps keep calcium out of your arteries. You've probably heard of atherosclerosis, more commonly called "hardening of the arteries." This disease is a process of calcification around microscopic amount of cholesterol that is cleaned up by a visible amount of white blood cells. Essentially, the white blood cells trying to remove cholesterol from the lining of the arteries get "stuck." They die - and attract still more white blood cells intended to remove them. Eventually the little bit of cholesterol and the lot of white blood cells calcifies and hardens, unless there has been adequate consumption of foods with vitamin K. The same vitamin K-directed process that keeps cartilage flexible also seems to encourage flexibility in the arteries. Flexible arteries carry blood at lower pressure, and are less at risk for heart attack and stroke. What are the foods with vitamin K? Here's a brief list:
The very best sources of foods with vitamin K are green leafy vegetables. Raw amaranth leaves, raw parsley, raw Swiss chard, cooked kale, raw watercress, cooked spinach, raw spinach, cooked turnip greens, raw collards, and cooked collards are the most highly concentrated foods with Vitamin K, in that order. Just a little farther down the list are a few exotic foods, lamb's quarters (the plant, not the meat), chrysanthemum leaves (served with Japanese food) and chicory among them. Almost any vegetable contains at least a little vitamin K. To get the benefit of foods with vitamin K, you need at least a little oil in cooking or dressing them. Olive oil works best. Vitamin K is fat soluble, and you can't get vitamin K into your system unless it is carried by fat. How much vitamin K do you need? As a general rule, your diet should include foods with vitamin K to give you about a milligram (1,000 micrograms) a week. That's a mere 2 cups of chopped raw kale. Or 10 cups of lettuce. (Think in terms of filling one shelf in your refrigerator with lettuce, then eating it all yourself.) You could also get all your vitamin K for a week by eating a small jar of mayonnaise, but it really isn't necessary to pack on the pounds or to turn green with chlorophyll just to be sure you get your vitamin K. Vitamin K is available in supplements. Although allergic reaction is remotely possible, there is no known toxicity associated even with high doses of phylloquinone (vitamin K1, the kind of vitamin K found in food), or menaquinone (vitamin K2, a form of the vitamin found in supplements made in Japan). Where you would need to be careful is taking supplements made with menadione, also known as vitamin K3. This form of the vitamin, however, is not available in supplements sold in North America or Europe.
Just be sure your vitamin K comes in a formula that doesn't have to be taken with food. You're also better off if your K is part of a complete nutritional supplement you can easily remember to take. There are more reasons to eat your greens than just vitamin K, so it's a good idea to eat some kind of dark, green leafy vegetable several times week. For your vitamin K 'insurance," however, take supplemental K.
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