The number one cause of this type of anemia, however, is iron deficiency.An insufficient intake of iron, Vitamin B12, and folic acid impairs the bone marrow function. The lack of iron within a person’s body can also stem from ulcer bacteria. These microbes live in the digestive tract and after many years cause ulcers in the lining of the stomach or small intestine. Therefore, a high percentage of patients with nutritional anemia may have a potential gastrointestinal disorder that causes chronic blood loss. This is common in immunocompromised, elderly, and diabetic people. High blood loss can also come from increased loss of blood during menstruation, childbirth, cancers of the intestines, and disorders that hinder the blood’s ability to coagulate. Medications can have adverse effects and cause nutritional anemia as well. Medications that stop the absorption of iron in the gut and cause bleeding from the gut (NSAIDs and Aspirin) can be culprits in the development of this condition. Hydrocortisones and valproic acid are also two drugs that can cause moderate bleeding from the gut. Amoxicillin and phenytoin have the ability to cause a vitamin B12 deficiency. Other common causes are thyroid disorders, lead toxicity, infectious diseases (e.g malaria), alcoholism, and vitamin E deficiency. Diagnosis
Complete blood count. Acute phase reactants
Serum iron studies 
Peripheral blood morphology

Types of nutritional anemia
Iron Deficiency Anemia
It is the last stage of iron deficiency and it is characterized by the production of small (microcytic) erythrocytes and diminished level of circulating hemoglobin. It represents the end point of a long period of iron deprivation.
Megaloblastic Anemia
It reflects DNA disturbance which affects the blood cells (erythrocytes, leukocytes, platelets) and the bone marrow, and it is characterized by large and immature blood cells in the bone marrow (macrocytic anemia), mainly caused by both vitamins B9 (Folic Acid) and B12. Anemia of Protein-Energy Malnutrition
As explained before, hemoglobin is a protein which means that its production requires adequate and enough intake of protein from the diet, but in case of protein-energy malnutrition, hemoglobin will not be produced sufficiently leading to anemia. As a result there is a reduction in cell mass and thus fewer RBCs are required to oxygenate the tissue ( reduced number of RBCs with a low hemoglobin). Copper Deficiency Anemia
Copper and copper proteins are needed for adequate hemoglobin formation, use of iron by the developing erythrocyte (ceruloplasmin), optimal functions of the erythrocyte membrane. Ceruloplasmin (copper containing protein) is required for normal mobilization of iron from its storage sites. Thus, in a copper- deficient state; iron cannot be released à low serum iron and hemoglobin levels (even in the presence of normal iron stores). Sideroblastic Anemia
It is an inherited defect of heme synthesis enzyme which results in derangement in the final pathway of heme synthesis and buildup of immature Fe- containing RBCs. It is classified as microcytic and hypochromic type of anemia and it is nutritional because it is Vitamin B6-responsive. Hemolytic Anemia
A defect in RBC membranes causes oxidative damage and lysis the cells. Vitamin E has shown to be protective as it has an antioxidative function.