Malabsorption
From Wikipedia:
"Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal(GI) tract.
Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and variety of anaemias."
For a full medical explaination and breakdown of Malabsorption please check out the following page: Wikipedia
