Anemia results from reduced red blood cells. It is caused due to various reasons like:

• Reduced production of red blood cells as in iron deficiency anemia or megaloblastic anemia
• Excess blood loss: blood loss can be due to external bleeding like in road traffic accidents or internal bleeding as in hookworm infection, Excess bleeding during periods (menstruation), long term use of drugs like aspirin or pain killers, etc
• Destruction of the red blood cells: Hemolytic anemias
• Autoimmune conditions like rheumatoid arthritis, systemic lupus erythematosus, etc

Risk factors include:

• Malnutrition - low iron diet, Vitamin B12 and folate
• Problems in absorption of nutrients due to conditions like Crohn's disease or Celiac disease
• Excessive bleeding during menstruation
• Lack of balanced diet during pregnancy
• Family history

Few of the causes of anemia like iron deficiency anemia or megaloblastic anemia can be prevented by:

• Consuming healthy diet rich in iron
• Consuming Vitamin B12 and folic acid
• Increasing the intake of vitamin C, as it helps in better absorption of iron from food
• Reducing tea and coffee intake as it reduces the absorption of iron from food