Chocolate & Vitamin K

Vitamin K, associated with blood clotting, helps blood to coagulate. Cocoa powder, although not rich in vitamin K, contains trace amounts of the vitamin, and milk chocolate made with fortified dairy can contain a little more. Furthermore, chocolate cakes and brownies sometimes contain moderate sources of vitamin K, if they are made with fortified flour or egg yolks.

Functions of Vitamin K

Vitamin K represents five fat-soluble substances essential for blood clotting, also known as coagulation. Vitamins K1 and K2 are derived from plant and animal sources, while K3, K4 and K5 are synthetic versions used to fortify certain foods. Vitamin K is named after the German word, "koagulation," discovered by a Danish researcher in 1929, according to "The Vitamins." Specifically, vitamin K works as a cofactor for an enzyme that catalyzes glutamic acid into gamma-carboxyglutamic acid, which helps the coagulation cascade occur. Coagulation stops blood flow by forming clots, a process essential for healing injuries. Chocolate contains compounds that can affect blood platelets, but it does not interfere with the actions of vitamin K.

Recommended Level and Deficiency

In 2001, the Food and Nutrition Board of the Institute of Medicine established the adequate intake levels for vitamin K based on consumption levels of healthy individuals. The adequate vitamin K intake level for male adults is 120 mcg per day and 90 mcg per day for female adults, including those who are pregnant and breast feeding. Vitamin K deficiency can be found among malnourished children and can occur in adults who take anticoagulant drugs or have problems absorbing fat. According to "Human Biochemistry and Disease," symptoms of vitamin K deficiency include an increase in clotting time, bruising, nosebleeds, bleeding gums, anemia and heavy menstruation.

Nutritional Content of Chocolate

Chocolate, made from cocoa beans, grows on cacao trees and contains beneficial nutrients. Dark chocolate, for example, contains a higher percentage of cocoa powder and is considered a fairly good source of minerals and trace elements, especially magnesium, copper, iron and calcium. As a plant-derived substance, cocoa beans contain some vitamin K1, but only in trace amounts. Milk chocolate contains less cocoa powder, but more dairy products. As such, milk chocolate sometimes contains trace amounts of vitamin K2, depending on the amount of dairy ingredients used. Because egg yolks, vegetable oils and some flours are good sources of vitamin K, baked goods such as chocolate cake, chocolate muffins and brownies can provide moderate amounts of the vitamin.

Natural Sources

Rich sources of vitamin K1 include spinach, broccoli, Brussels sprouts, Swiss chard, avocado, parsley, kiwifruit and vegetable oils, such as soybean, canola and olive. Rich sources of vitamin K2 include meat, egg yolks and some cheeses.

References

• "The Vitamins, Third Edition"; Gerald F. Combs; 2007
• "Advanced Nutrition: Macronutrients, Micronutrients, and Metabolism"; Carolyn D. Berdanier; 2009
• "Human Biochemistry and Disease"; Gerald Litwack; 2008
• "American Dietetic Association Complete Food and Nutrition Guide"; American Dietetic Association; 2006