The five possible causes of all nutrient deficiency: illustrated by deficiencies of vitamin B 12 and folic acid.
D001646:Bile / Q000032:analysis; D001693:Biological Transport, Active; D004798:Enzymes / Q000378:metabolism; D005492:Folic Acid / Q000378:metabolism; D005494:Folic Acid Deficiency / Q000201:enzymology / Q000209:etiology*; D005508:Food Deprivation; D005750:Gastric Juice / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D007411:Intestinal Diseases, Parasitic / Q000150:complications; D009748:Nutrition Disorders / Q000175:diagnosis / Q000209:etiology; D009751:Nutritional Requirements; D010672:Phenytoin / Q000378:metabolism; D011086:Polycythemia / Q000097:blood; D014805:Vitamin B 12 / Q000378:metabolism; D014806:Vitamin B 12 Deficiency / Q000201:enzymology / Q000209:etiology*
D004798:Enzymes; D010672:Phenytoin; D005492:Folic Acid; D014805:Vitamin B 12