First, let's define some terms. Iron deficiency anemia, or IDA, is a common type of anemia. In fact, about 5% of American women and 2% of American men overall have it.1 It's a condition in which blood lacks an adequate supply of healthy red blood cells. These cells carry oxygen to tissues and cells. It is oxygenated blood that sustains life as well as gives your body energy and your skin a healthy color.
As the name suggests, IDA results from insufficient iron. Your body needs iron to make a substance called hemoglobin. It's the hemoglobin in red blood cells that enables them to carry oxygen.
Some of the more common reasons for low iron are heavy menstrual bleeding, pregnancy (when the need for iron is especially high), as well as chronic gastrointestinal bleeding and malabsorption syndromes.
1 Johnson-Wimbley TD, Graham DY. Diagnosis and management of iron deficiency anemia in the 21st century. Therap Adv Gastroenterol. 2011;4(3):177-184.