Final answer:
Iron Deficiency Anemia in adults is most commonly due to inadequate dietary iron intake or malabsorption issues. Chronic liver failure and surgery affecting the GI tract also contribute to the condition. It is not typically caused by excessive iron absorption or genetic predispositions.
Step-by-step explanation:
Adults most often contract Iron Deficiency Anemia (IDA) due to inadequate dietary iron intake. This condition arises when the body doesn't have enough iron to produce the required amount of heme for red blood cells. Certain groups are more susceptible to IDA, including those with dietary restrictions like vegans and vegetarians. This is because the iron in plant-based foods is less readily absorbed by the body due to the presence of phytates. Additionally, malabsorption syndromes can prevent iron from being absorbed properly even if dietary intake is sufficient.
Chronic conditions such as chronic liver failure, which can be caused by cirrhosis from various factors including hepatitis and excessive alcohol intake, can contribute to IDA. Removal of significant sections of the gastrointestinal tract or stomach also impairs the body's ability to absorb iron. Though iron overload conditions such as hemosiderosis and hemochromatosis exist, they do not cause IDA; instead, they involve the deposition of excess iron in body tissues.
Iron deficiency anemia is the most common nutritional deficiency worldwide and unlike IDA caused by genetic predispositions, chronic infection, excessive iron absorption, or conditions such as siderosis and nutritional siderosis, the main cause for most adults is a lack of dietary iron or issues with absorption.