Vitamin K is a fat-soluble micronutrient that your body requires to produce blood-clotting proteins. The form of vitamin K in food is called K1, or phylloquinone. Because vitamin K does not dissolve in water, it can only be absorbed from your small intestine in combination with fat. Fat malabsorption describes any medical condition that interferes with fat digestion and absorption. Deficiencies of the fat-soluble vitamins, including vitamin K, can develop if you have a medical condition that causes fat malabsorption.
Absorption of dietary vitamin K from your small intestine depends on normal fat digestion. As food containing vitamin K and fats enters your small intestine, your pancreas and gallbladder release digestive enzymes and bile, respectively. Bile emulsifies dietary fats and fat-soluble vitamins, breaking large fat globules into tiny droplets that remain suspended in the water-based mixture of food in your intestine. The result is similar to what happens when you shake oil and vinegar together for salad dressing; the oil breaks into tiny droplets that mix with the vinegar. Enzymes from your pancreas attach to the tiny fat droplets and digest them into minute fat molecules that your intestinal cells can absorb. Inadequate secretion of bile or fat-digesting enzymes leads to incomplete fat digestion, with a related decrease in absorption of both dietary fat and any accompanying fat-soluble vitamins. Severe liver, gallbladder or pancreatic disease can lead to fat malabsorption and deficiencies of the fat-soluble vitamins K, A, D and E.
In some cases, fat digestion proves normal, but absorption by your intestinal cells is impaired. This may occur with inflammation caused by Crohn's disease, ulcerative colitis or celiac disease. Surgical removal of a large segment of your small intestine and certain types of weight-loss surgery can also interfere with your absorption of dietary fat and fat-soluble vitamins.
Signs and Symptoms
Significant fat malabsorption typically causes distinct gastrointestinal symptoms, including bloating of your abdomen, excess intestinal gas, diarrhea, greasy or oily stools, an intensely foul odor associated with your stools, and unintentional weight loss. A vitamin K deficiency caused by fat malabsorption may disrupt normal blood clotting, potentially leading to easy bruising, frequent nosebleeds, bleeding from your gums, heavy menstrual bleeding, and prolonged bleeding with minor cuts or scrapes.
A vitamin K deficiency caused by fat malabsorption typically requires a two-pronged treatment approach. In the short term, your doctor may prescribe vitamin K supplements to correct the deficiency and restore your normal blood-clotting capacity. Treatment of the underlying condition causing the fat malabsorption also proves important for your overall health. The specific treatment plan varies, depending on the nature of your underlying disease. With chronic fat malabsorption, you may need to take vitamin K supplements indefinitely.
- "The Merck Manual for Healthcare Professionals"; Vitamin K; Larry E. Johnson, M.D., Ph.D.; April 2007
- Colorado State University Pathophysiology Hypertext; Vitamin K; Richard Bowen, D.V.M., Ph.D.; July 1999
- Colorado State University Pathophysiology Hypertext; Absorption of Lipids; Richard Bowen, D.V.M., Ph.D.; August 2007
- NYU Langone Medical Center: Malabsorption
- "Harrison's Principles of Internal Medicine, 16th Edition"; Dennis L. Kasper, M.D., et al., Editors; 2004