We are more vulnerable to anemia in certain phases of our life such as adolescence, since it need a high intake of iron, an essential element for the production of hemoglobin. A lack of sufficient, not only of iron but of vitamins and trace elements necessary for optimal assimilation will happen inevitably a decrease in the number of red cells in blood, which carry oxygen to tissues.
Even earlier, during lactation, the lack of variety in the diet often does require intervention by the doctor who can prescribe extra-complex vitamins or iron inputs. Children are also susceptible population by the tremendous needs precise iron accelerated growth.
Women during their menstrual period are also at risk population for anemia, especially those with heavy periods, due to its periodic loss of blood, and therefore iron. Even in this period in the only time they stop menstruating, during pregnancy, is even more necessary to monitor levels of hemoglobin, since the mother must not only maintain their own body, but must also provide all the nutrients the fetus.
People who follow vegetarian diets in which not consuming vitamin B12 (essential for red blood cells) that only provides the meat, or dieting without medical criteria, are also a population at risk of anemia.
The red blood cells are responsible for transporting oxygen from lungs to different tissues. When for any reason reduces the number of red blood cells, also decreases the oxygen supply to the various organs of our body, causing the sensation of fatigue so characteristic of anemia.