Links to Studies on Changes in Taste Perception after RNY

Bariatric surgery and taste: novel mechanisms of weight loss http://www.mendeley.com/research/bariatric-surgery-taste-novel-mechanisms-weight-loss/ Abstract PURPOSE OF REVIEW: The mechanisms by which obesity surgery and in particular gastric bypass cause weight loss are unclear. The review will focus on the concept of alterations in the sense of taste after obesity surgery. RECENT FINDINGS: Patients after obesity surgery and gastric bypass in particular change their eating behaviour and adopt healthier food preferences by avoiding high-calorie and high-fat foods. Patients find sweet and fatty meals less pleasant not due to postingestive side effects but through changes in the sense of taste. The acuity for sweet taste increases after gastric bypass potentially leading to increased intensity of perception. Obese patients experience higher activation of their brain taste reward and addiction centres in response to high calorie and fat tasting. Gastric bypass may reverse these taste hedonics, perhaps through the influence on gustatory pathways caused by enhanced gut hormone responses after surgery. SUMMARY: Elucidation of the metabolic mechanism behind the alterations in taste after obesity surgery could lead to the development of novel surgical and nonsurgical procedures for the treatment of obesity. ____________________________________________________________ Taste Acuity Of The Morbidly Obese Before and After Gastric Bypass Surgery http://scholar.google.com/scholar_url?hl=en&q=http://www.springerlink.com/index/v33hk5766341qn8j.pdf&sa=X&scisig=AAGBfm3MKIWbrYjkDlE3k-HC-IUp9DN-lw&oi=scholarr Abstract Obese individuals have an increased preference for high caloric foods, such as sweets and fats. However, following gastric bypass (GBP) surgery, morbidly obese patients tend to avoid these foods. We hypothesize that this aversion may occur, in part, from permutations in taste acuity. To test this hypothesis, taste detection and recognition thresholds for the four basic tastes (salt, sweet, sour, and bitter) were assessed using a modification of the Henkin forced choice three stimulus technique. Taste acuity measurements were obtained at baseline and at 30, 60, and 90 days post-operative for six morbidly obese GBP women and ten non-surgical, lean female controls. We found non-significant differences in taste detection and recognition thresholds between morbidly obese and lean control study subjects at baseline, and no significant correlation between taste acuity and body size. Furthermore, in our study population of lean and obese women, ages 26 to 52, there were no significant interrelationships between baseline taste thresholds and known effectors of taste acuity, i.e., zinc levels, glycemic status, liver and kidney function, or age. Following GBP surgery, a significant up-regulation in taste acuity for bitter and sour was observed along with a trend toward a reduction in salt and sweet detection and recognition thresholds. These findings would suggest the following: (1) taste acuity does not influence taste preferences of the obese individual who has not had bariatric surgery; (2) taste effectors such as zinc, when within the range of normal values, do not alter thresholds of the 4 basic tastes; and (3) weight loss following gastric bypass surgery is associated with an up-regulation in taste acuity in the morbidly obese. Studies are currently under investigation at our center to identify the specific etiology of taste acuity upregulation in the morbidly obese following GBP surgery. ___________________________________________________ Taste change after laparoscopic Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding http://scholar.google.com/scholar_url?hl=en&q=http://www.sciencedirect.com/science/article/pii/S1550728906001377&sa=X&scisig=AAGBfm0E3me9DwpuL3hs5nS7RVc5i1-4AQ&oi=scholarr F Abstract Background Many patients have described changes in taste perception after weight loss surgery. Our hypothesis was that patients develop postoperative changes in taste that vary by bariatric procedure. Methods Patients who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic adjustable gastric banding (LAGB) completed a 23-question institutional review board–approved survey postoperatively regarding their degree and type of taste changes and food aversion and how these influenced their eating habits. Results A total of 127 patients participated. After removing the inadequately completed surveys, 82 LRYGB and 28 LAGB patients were included. Of these, 87% of LRYGB and 69% of LAGB patients believed taste is important to the enjoyment of food. More LRYGB patients (82%) than LAGB patients (46%) reported a change in the taste of food or beverages after surgery (P <.001). In addition, 92% of LAGB versus 59% of LRYGB patients characterized the change as a decrease in the intensity of taste (P <.05). Additionally, 68% of LRYGB and 67% of LAGB patients found certain foods repulsive and had developed aversions. Also, 66% of LRYGB and 70% of LAGB patients believed the taste changes were greater than expected preoperatively. Most patients (83% of LRYGB and 69% of LAGB patients) agreed that the loss of taste led to better weight loss. Conclusion Although most LRYGB and many LAGB patients experienced taste changes and food repulsion postoperatively, procedural differences were found in these taste changes. Taste changes need to be investigated further as a possible mechanism of weight loss after bariatric surgery. MY APOLOGIES FOR THE LACK OF FORMATTING. THIS WAS DONE FROM MY iPad.