An important vitamin to lack is Vitamin C.

This vitamin does double-duty as an antioxidant: It helps block cell mutations triggered by dangerous free radical molecules.  It also aids wound healing cartilage, repair and the maintenance of strong bones and teeth. Studies show how people who take Vitamin C supplements on a regular basis have milder symptoms and shorter colds.  Signs you are lacking this vitamin: fatigue, muscle and joint pain, easy bruising, dry skin, swollen or discolored gums and poor wound healing.  Chronic deficiency (that lasts three months or more) can lead to an illness called scurvy.  This can cause lethargy and in advanced cases jaundice and fever.  Women need 75 milligrams a day.  Men need 90 milligrams a day.  You can get more of this vitamin from citrus fruits such as cantaloupe, kiwi, mango, papaya, pineapple and berries. Also from eating broccoli, Brussels sprouts, spinach, leafy greens, potatoes and winter squash.