Micronutrient deficiencies after gastric bypass for morbid obesity.

Gastric stapling for morbid obesity has been popularized, in part, because of an apparent lack of metabolic sequelae. Of our series of prospectively studied gastric bypass patients, 74 patients have been followed for more than 1 year. Anemia developed in more than one-third of the patients. Nearly two-thirds of the patients developed decreased levels of vitamin B12, and other abnormalities were commonly seen (folate, 38%; iron, 49%; potassium, 56%). While prompt recognition and treatment has prevented development of a clinical deficiency syndrome in most patients, 12 per cent became anemic most likely because of micronutrient deficiency related to the bypass. More than 10,000 gastric restriction operations are carried out for morbid obesity each year in this country. Previous reports of thiamine deficiency-related neurologic sequelae, immune paralysis, and marrow suppression, together with the micronutrient deficiencies and anemia herein reported make long-term frequent metabolic assessment of these patients essential.