Hemoglobin binds to oxygen, enabling red blood cells to supply oxygenated blood throughout the body. Women of child-bearing age, children, and people with poor diet are most susceptible to the disease. Most cases of iron-deficiency anemia are mild, but if not treated can cause problems like an irregular heartbeat, pregnancy complications, and delayed growth in infants and children that could affect their cognitive development and their behavior. Signs and symptoms
Symptoms of iron deficiency can occur even before the condition has progressed to iron deficiency anemia. Symptoms of iron deficiency are not unique to iron deficiency (i.e. not pathognomonic). Iron is needed for many enzymes to function normally, so a wide range of symptoms may eventually emerge, either as the secondary result of the anemia, or as other primary results of iron deficiency. Symptoms of iron deficiency include:
fatigue
dizziness/lightheadedness
pallor
hair loss
twitches
irritability
weakness
pica
brittle or grooved nails
hair thinning
Plummer–Vinson syndrome: painful atrophy of the mucous membrane covering the tongue, the pharynx and the esophagus
impaired immune function
pagophagia
restless legs syndromeContinued iron deficiency may progress to anemia and worsening fatigue. Thrombocytosis, or an elevated platelet count, can also result. A lack of sufficient iron levels in the blood is one reason that some people cannot donate blood. Signs and symptoms in children
pale skin
fatigue
slowed growth and development
poor appetite
decrease in the size of testes
behavioral problems
abnormal rapid breathing
frequent infection

Iron requirements in young children to teenagers
Causes
blood loss (hemoglobin contains iron)
donation
excessive menstrual bleeding
non-menstrual bleeding
bleeding from the gastrointestinal tract (anus) (ulcers, hemorrhoids, ulcerative colitis, stomach or colon cancer, etc.)
Low serum ferritin (see below)
Low serum iron
High TIBC (total iron binding capacity), although this can be elevated in cases of anemia of chronic inflammation. It is possible that the fecal occult blood test might be positive, if iron deficiency is the result of gastrointestinal bleeding; although the sensitivity of the test may mean that in some cases it will be negative even with enteral blood loss.As always, laboratory values have to be interpreted with the labs reference values in mind and considering all aspects of the individual clinical situation. Serum ferritin can be elevated in inflammatory conditions; so a normal serum ferritin may not always exclude iron deficiency, and the utility is improved by taking a concurrent C-reactive protein (CRP). The level of serum ferritin that is viewed as "high" depends on the condition. For example, in inflammatory bowel disease the threshold is 100, where as in chronic heart failure (CHF) the levels are 200. Treatment
Before commencing treatment, there should be definitive diagnosis of the underlying cause for iron deficiency. This is particularly the case in older patients, who are most susceptible to colorectal cancer and the gastrointestinal bleeding it often causes. In adults, 60% of patients with iron-deficiency anemia may have underlying gastrointestinal disorders leading to chronic blood loss. It is likely that the cause of the iron deficiency will need treatment as well. Upon diagnosis, the condition can be treated with iron supplements. The choice of supplement will depend upon both the severity of the condition, the required speed of improvement (e.g.