A patient with a history of gastrointestinal surgery presents with symptoms of megaloblastic anemia. Which of the following nutrients is most likely deficient in this patient?

A Vitamin B12
B Folate
C Iron
D Vitamin C
Gastrointestinal surgery can lead to impaired absorption of vitamin B12, resulting in megaloblastic anemia.
Guyton and Hall Textbook of Medical Physiology
Metabolic and Nutritional Disorders Nutrition and Health Nutrient Deficiencies and Disorders Medium MEDICAL Confidence: high