Final answer:
Pernicious anemia is caused by a lack of intrinsic factor which is required for vitamin B12 absorption, leading to a deficiency in producing healthy red blood cells. It can be associated with certain diseases or surgical conditions. Iron deficiency anemia and megaloblastic anemia are also common forms of anemia related to nutrient deficiencies.
Step-by-step explanation:
A lack of intrinsic factor and/or vitamin B12 may cause the form of anemia called pernicious anemia. Pernicious anemia is characterized by the body's inability to absorb sufficient vitamin B12 due to the lack of intrinsic factor, which is crucial for vitamin B12 absorption in the intestine. Without adequate vitamin B12, the production of healthy red blood cells is impaired, leading to anemia. This condition can be seen in various circumstances, including individuals with Crohn's disease, post-surgery of the stomach or intestines, those with intestinal parasites, and AIDS patients.
It is also important to note that iron deficiency anemia and megaloblastic anemia are also related to deficiencies in essential nutrients such as iron, vitamin B12, and folate. These vitamin-deficient anemias can affect teens, children, vegans, and vegetarians more frequently due to dietary restrictions or lack of certain foods in their diet. Special attention is needed to ensure pregnant women receive sufficient folic acid to avoid the risk of neurological defects in the developing fetus