Do you bruise easily? Have trouble seeing at night? It could be signs that your body needs more of the fat-soluble vitamins. Deficiency is common and those of us on a special diet due to food allergies or celiac disease may be at increased risk. There are two types of vitamins: water soluble, such as B vitamins and C, and fat soluble, such as vitamins A, D, E and K. Fat-soluble vitamins are essential for normal functioning of the immune system, digestive system, blood clotting mechanisms and more. Absorption of fat-soluble vitamins requires lipase, a digestive enzyme secreted at the tips of the intestinal villi. Symptoms of deficiency are often overlooked.