Taste Changes after Bariatric Surgery: What to Do when Your Patients Cannot Stand the Taste of Their Food

| May 16, 2012

Nutritional Considerations in the Bariatric Patient

This month: Taste Changes after Bariatric Surgery:  What to Do when Your Patients Cannot Stand the Taste of Their Food

This Month’s Contributor: Jennifer Traub, RD, CNSC, Clinical Dietitian, Hurley Bariatric Center, Flint, Michigan

Bariatric Times. 2012;9(5):14–15

Abstract
After undergoing bariatric surgery, some patients have reported that their foods and/or beverages smell or taste bad or different to them. While taste and smell dysfunction might actually help prevent postoperative overeating in the bariatric surgery patient, it can also lead to anxiety and depression as well as anorexia and nutritional deficiencies. This article reviews the available literature on taste changes after bariatric surgery and discusses treatment considerations for the clinician working with such patients.

Introduction
Complaints of taste changes after bariatric surgery, especially following Roux-en-Y gastric bypass (RYGB), are nothing new. Nearly 17 years ago, in a 1995 issue of the Journal of the American Dietetic Association, findings from a study designed to assess changes in taste acuity following RYGB demonstrated all participants reported a heightened sensitivity to sweet tastes.[1] Since then, there have been several investigations into the variance in sense of taste, as well as sense of smell, that sometimes follow bariatric surgery. One study[2] found that RYGB decreased preference for sweet-tasting substances in obese rats, however, it is interesting to note that researchers did not observe a similar decrease in preference for salty, sour, or bitter substances.

Findings reported in a 2006 issue of Surgery for Obesity and Related Diseases also support that many patients experience taste changes and food repulsion following bariatric surgery.[3] Such disorders of taste and smell, referred to as dysguesia and dysosmia, respectively, have the potential to dramatically affect an individual’s ability to get adequate nutrition following bariatric surgery.[4]

In the following sections, I will discuss possible causes of these sensory changes and make suggestions on how can we help our patients experiencing them.

Possible Causes
Disorders of taste and smell may be overlooked in aspects of medical practice because these senses are not considered critical to life. However, it is important to diagnose and treat dysguesia and dysosmia because these disorders could possibly lead to nutritional deficiencies (which in turn could cause other more severe problems), if they prevent a patient from consuming adequate food and/or supplements.

Before diagnosing a patient with dysguesia and dysosmia, the clinician should review current laboratory data to rule out possible mineral deficiencies (e.g., zinc, copper, nickel) and investigate medication side effects as potential etiologies for their symptoms.[4]

Ghrelin, an appetite-stimulating hormone primarily secreted by cells in the stomach and proximal small intestine, is significantly reduced following RYGB and sleeve gastrectomy (SG).[5] In a 2011 study, Tong et al[6] described the survival-based role ghrelin plays in enhancing exploratory sniffing and olfactory sensitivity in order to locate, identify, and select foods. They found that lower ghrelin production equaled increased satiety, and that “pleasantness ratings” for food odors are significantly and specifically reduced in satiated humans. Tong et al also studied ghrelin receptors in olfactory bulbs and in the brain centers that process olfactory signals, and reported that there was clearly detectable binding of biotinylated ghrelin in the olfactory bulb, suggesting that ghrelin is involved in olfactory processing. Biotinylated ghrelin binding was also detected in the hippocampus. Tong et al concluded that ghrelin modulates olfactory behavior and was shown to enhance sniffing and odor detection in rats as well as exploratory sniffing in humans.

Effects
While there is a lack of literature available describing the long-term effects on sensory changes following weight loss surgery, in my practice, I find such changes often bring about feelings of anxiety and frustration as patients might not understand why their sense of taste and/or smell has changed, or they may worry about being able to meet their nutritional needs due to aversions to various foods or supplements.

Treatment Suggestions
As a clinician, I often hear from patients post RYGB and SG complaints that their foods and/or beverages smell or taste “foul,” “bad,” or “strong.” I have found that directing patients to focus on enhancing salty, acidic, or bitter foods helps. For example, patients might consider consuming plain versus fruit-flavored yogurt; using lemon juice to season vegetables, meat, and fish; or adding unflavored protein powder to low-sodium broths or naturally bitter herbal teas, such as chamomile and mint. These substitutions and additions to a patient’s diet may help to ensure adequate protein and fluid intake throughout the day.

There are numerous protein supplement products on the market today. It is important that the clinician suggest that the patient try more than one brand or flavor of protein drink/powder, in order to find one he or she likes, or at least can tolerate reasonably well. Some manufacturers sell samples of their flavor varieties so less cost is expended in pursuit of a tolerable protein supplement.

Because taste is very subjective, I also encourage patients to find spices or seasonings they find the least offensive and rely on them daily to prevent malnutrition associated with food avoidance.

In 2008, a case study on RYGB[7] detailed how postoperative food aversions, taste changes, and loss of appetite affected one patient and described nutrition intervention techniques employed by the treating clinician. At seven weeks post-RYGB, the patient had lost 47 pounds, but due to lack of appetite, the result of a “phobia” of food textures and taste alterations, her dietary intake had not progressed beyond clear liquids. The patient complained of a “gag response” when eating, or even thinking about eating, certain foods. The nutritional intervention employed by the treating registered dietitian (RD) focused on adding all textures and types of foods back into the diet with sips of water to cleanse the mouth after eating. Additionally, the patient adhered to bi-weekly and eventually monthly phone visits with the RD to review oral intake. During these phone calls, the RD provided encouragement and emotional support to the patient. At one year postoperative, the patient had achieved a total weight loss of 109 pounds and was tolerating all foods with the exception of hamburger and breads.[7]

Conclusion
There is still much to learn about post-bariatric-surgery dysguesia and dysosmia. Until more long-term studies are done to help us further understand the root cause(s) and the effectiveness of treatment strategies, we must rely heavily on our own experience and critical thinking skills if we are to help those patients who are struggling with taste and/or smell dysfunction. Due diligence in ruling out any nutritional deficiencies or medication side effects that might be contributing to the sensory dysfunction should be performed and addressed if indicated. In the end, prompt nutritional intervention, using the suggestions listed in this article, can make all the difference in the health and quality of life of the surgical weight loss patient dealing with these issues.

References
1.    Burge J, Schaumburg J, Choban P, et al. Changes in patients’ taste acuity after Roux-en-Y gastric bypass for clinically severe obesity. J Am Diet Assoc. 1995;95:666–670.
2.    Gastric bypass alters sweet taste function; finding could lead to safer treatments for morbid obesity. Science Daily. Nov 2, 2010. http://www.sciencedaily.com/releases/2010/11/101102130949.htm Accessed 1/18/2012.
3.    Tichansky DS, Boughter JD, Madan, AK. Taste change after laparoscopic Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding. Surg Obes Relat Dis. 2006; 2(4):440–444.
4.    Leopold D. Disorders of taste and smell. Medscape Reference. 2012. http://emedicine.medscape.com/article/861242-overview. Accessed 2/6/2012.
5.    Cummings D, Shannon M. Ghrelin and gastric bypass: Is there a hormonal contribution to surgical weight loss? J Clin Endocrinol Metab. 2003;88(7):2999–3002.
6.    Tong J, Mannea, E, Aime P, et al. Ghrelin enhances olfactory sensitivity and exploratory sniffing in rodents and humans. Journal of Neuroscience. 2011;31(15):5841–5846.
7.    Benson-Davies S, Quigley D. Food aversions and taste changes following Roux-en-Y gastric bypass surgery. Topics in Clinical Nutrition. 2008;23(4):357–363.

Funding: No funding was provided in the preparation of this manuscript.

Financial disclosures: The author reports no conflicts of interest relevant to the content of this article.

Category: Nutritional Considerations in the Bariatric Patient

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