Table 5.

Operations in the gastrointestinal tract – sequelae which can trigger micronutrient deficiencies and/or an increased requirement of micronutrients

Organ/affected micronutrient group	Deficiency of/elevated requirement for
Stomach (e.g. gastrectomy)
Vitamins	vitamin B12 (from intrinsic factor deficiency), vitamins A, D, E, K, carotinoids (e.g. lycopene), folie acid (as a result of reduced pH gradients in the duodenum), vitamin C
Minerals	calcium (as a result of lactose intolerance, anacidity), magnesium
Trace elements	zinc, iron (as a result of anacidity), selenium
Small intestine (e.g. small bowel resection)
Vitamins	vitamin B12 (resulting from microbial imbalance/dysbiosis); vitamins A, D, E, K, carotinoids (as a result of steatorrhea)
Pancreas (e.g. pancreatectomy)
Vitamins	vitamins A, D, E, K, carotinoids (from steatorrhea), vitamin B12
Vitaminoids	coenzyme Q10
Essential fatty acids	omega 3 fatty acids (from steatorrhea)