To the Editor:  

We have treated several patients who had undergone laparoscopic gastric bypass or gastric banding surgery and later presented to our emergency department with intolerance to food intake because of nausea and vomiting. After radiologic examinations showed no obstructions, we interviewed these patients and discovered that their food intolerance was related to parosmia or nausea after smelling foods that had given them no problems before surgery. The onset of symptoms in these patients varied from a few months to several years after the bariatric operations. 

Postbariatric-surgery parosmia is a problem that occurs when patients are trying to maintain their nutritional intake but are having trouble doing so because of nausea brought on by the smell of liquids, foods, and oral dietary supplements. Discussions with surgical attending physicians at the hospital revealed that this problem has a low overall rate of occurrence, with most cases happening after gastric bypass rather than gastric banding. Time of onset of symptoms varies from a few months to several years after surgery. In general, the duration of the adverse effects is about 3 months for patients treated at our institution. 

We conducted an extensive search of the literature for studies of changes in eating habits and olfactory function in patients after gastric bypass or gastric banding surgery. We used the MED-LINE and PubMed databases, as well as Google, in our literature search. 

Adami et al¹ discussed food aversion resulting from distension of the gastric pouch above the Roux-en-Y limb or above the gastric band. Scruggs et al,² Benson-Davies and Quigley,³ and Tichansky et al⁴ described changes in taste acuity after gastric bypass and adjustable gastric banding, but they noted no definite etiologic factor or mechanism for these changes. Richardson et al⁵ reported increased olfactory dysfunction in patients with a body mass index greater than 45, relative to patients with a body mass index less than 45. However, they did not address postoperative changes in olfactory acuity. Leopold⁶ noted that causes of olfactory distortion may include upper respiratory infections, head trauma, allergic rhinitis, and chronic rhinosinusitis. Teruhiro et al⁷ added zinc deficiency and medication adverse effects to that list. We found no articles specifically addressing the occurrence of parosmia or the etiologic factors or mechanisms of parosmia after gastric bypass or gastric banding. 

The purpose of this letter is to bring to light the occurrence of postbariatric-surgery parosmia and the need for studies to find an etiologic factor and mechanism for this condition. At our institution, antiemetic agents are used along with a consultation with the dietary services department to treat patients with postbariatric-surgery parosmia. The typical dietary services recommendation in such cases has been for the patient to mix and match liquid and food intake until an appropriate combination is found that will not cause nausea.