By Dr. Joseph Mercola
     with Rachael Droege

You may have noticed on the site that I recommend vitamin K -- and even offer a proven brand -- because it's an extremely important but often overlooked nutrient for both heart disease and osteoporosis. Well, vitamin K also has anticancer effects and is useful in the treatment of many different types of cancer, including liver, colon, lung, stomach, nasopharynx, breast, oral and leukemia.

Most of the research has focused on synthetic vitamin K3 taken at high doses, and it is commonly being used with chemotherapy agents for enhanced effectiveness. However, I do not advise using the synthetic vitamin K3, but rather the plant-based vitamin K1 (phylloquinone) and bacterially produced vitamin K2 (menaquinone).

Studies have shown that vitamins K1 and K2 are also effective against cancer. For instance, one study, published in the September 2003 International Journal of Oncology, found that treating lung cancer patients with vitamin K2 slowed the growth of cancer cells, and previous studies have shown benefit in treating leukemia.

Further, a number of human trials have demonstrated the anticancer effects of vitamin K1. In a study published in the August 2003 Alternative Medicine Review, of 30 patients with hepatocellular carcinoma, a type of liver cancer, who took oral vitamin K1, the disease stabilized in six patients, seven patients had a partial response, seven others had improved liver function and in 15 patients the abnormal prothrombin normalized.

Typically, large doses of vitamin K are needed to achieve these types of effects. However, most of the commercially available supplements come in microgram doses. Vitamin K does occur naturally in dark green leafy vegetables like collard greens and spinach and in fermented foods like natto, a fermented soy product, but most people do not consume nearly enough of these foods to get the optimal amount of vitamin K.

If you have cancer, or a family history of it, I strongly recommend that you add a vitamin K supplement to your diet. I now offer the most potent disease-fighting form of this vitamin available -- vitamin K2 -- in supplemental form. Vitamin K2 is a newly available extract of natto that provides the highly bioavailable form of vitamin K2 as menaquinone MK-7. This exclusive patented formula of vitamin K2 is only available online here at Mercola.com.

Since vitamin K is not easily absorbed by the body, I advise you to take the vitamin K with any daily meal that includes fat, as an ounce or more of fat has been shown to optimize the vitamin's absorption.