In 1935 a Danish scientist came across a nutrient that he named “Koagulations”. This name, in Danish, means clotting. The nutrient that this scientist came across is now referred to as vitamin K (American Cancer Society). Vitamin K is a fat soluble essential nutrient that is not produced by the body. It is imperative that we receive this nutrient for proper blood clotting. Vitamin K is involved in the production of four of the thirteen proteins involved in normal blood clotting (Harvard School of Public Health). Vitamin K is also involved in bone density maintenance and may help decrease hip fractures in both men and women. There are three variations of vitamin K, vitamins K1, K2, and K3 (American Cancer Society). Vitamin K1 is also known as phylloquinone and is found in green leafy vegetables such as broccoli, brussel sprouts, and cabbage and also in some fruits such as kiwi, blackberries, and blueberries (Turner, Elaine). This form of the vitamin is best digested in the GI tract when eaten with fats. The second form is Vitamin K2. This form is called menaquinone and is produced by the natural flora (bacteria) found in the large intestine. It is produced as a byproduct of the bacteria’s metabolism and small amounts can be absorbed by the intestine. The third form of vitamin K is a synthetic or man-made form called Menadione also known as vitamin K3 (Turner, Elaine). This can be found in some supplements; however supplements are not usually necessary because a normal diet and an average bacteria load will supply enough for the average person. Men nineteen years and older are encouraged to take 120 micrograms a day in their diet, and women nineteen years and older 90 micrograms (Turner, Elaine). Only one in four people in the United States meet the goal for the intake of vitamin K (Harvard School of Public Health). Newborns are not born with many bacteria in their intestine and therefore are considered vitamin K deficient. Only small amounts of vitamin K pass from mother to fetus through the placenta, so when the baby is born it lacks a sufficient amount of vitamin K (Johnson, Larry). In order to combat the symptoms of vitamin K deficiency (hemorrhagic diseases and other clotting problems) newborns are injected with a shot of vitamin K to help with clotting in the first few weeks after birth (Turner, Elaine). For those who are at high risk for blood clots, including those with deep vein thrombosis, irregular rhythms of the heart, and pulmonary embolism your doctor may have prescribed anticoagulation medications such as Warfarin (Coumadin) for blood clot control (Johnson, Larry). It is important to know that these types of medications are vitamin K antagonists. This means that too much vitamin K in the diet may change the effectiveness of these specific medications. It is important to talk to your doctor about your diet to see what changes may be beneficial. There is no research thus far to indicate that the body can have too much vitamin K. The only problems that have surfaced have been in relation to those taking medications such as Coumadin for blood clot control (Turner, Elaine).
Vitamin K and Insulin
In a recent study it was found that Vitamin K additionally appeared to reduce resistance to insulin in men. Insulin moves sugar in the blood into cells, but for insulin resistant (those with diabetes) the sugar cannot be removed and, therefore, builds up. Unfortunately the same results were not found in women, as those administered the additional Vitamin K in the experiment showed no decrease in insulin resistance. It is not sure why the Vitamin K had no effect on women, but it is hypothesized that the extra vitamin amounts built up in the additional fatty tissue of the women rather than getting into the blood.
Effects of Aging
Vitamin K deficiency problems appear to be more common in the elderly than in the younger populations resulting in bone loss, osteoarthritis, hardening of the arteries, and fractures. This appears not to be a problem so much of lack of intake, but of inefficient metabolism of Vitamin K after menopause due to lower estrogen levels. Separately Vitamin K intake was analyzed for elderly men and appeared not to independently effect cardiovascular health, but did indicated a healthier lifestyle and diet, which reduced risk of hear disease.
Johnson, Larry. "Vitamin K". Merck Manual of Medical Information - Second Home Edition. 5/26/2010 http://www.merck.com/mmhe/print/sec12/ch154/ch154l.html
"The Nutrition Source; Vitamin K". Harvard School of Public Health. 5/26/2010 http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vitamin-k/index.html
Turner, Elaine. "Facts About Vitamin K". University of Florida; IFAS Extension. 5/26/2010 http://edis.ifas.ufl.edu/pdffiles/FY/FY20900.pdf
"Vitamin K". American Cancer Society. 5/26/2010 http://www.cancer.org/docroot/ETO/content/ETO_5_3X_Vitamin_K.asp?sitearea=ETO
“Vitamin K & Insulin”. Nutrition Action Health Letter 36.9 (2009): 11-11.
“Vitamin K Deficiency In the Elderly.” Nutrition Health Review: The Consumer’s Medical Journal .96 (2006): 16-16.