A Systematic Review of Salt Taste Function and Perception Impairments in Adults with Chronic Kidney Disease

Abstract

Individuals with chronic kidney disease (CKD) experience physiological changes that likely impair salt taste function and perception. Sodium restriction is a cornerstone of CKD management but dietary sodium plays an important role in food enjoyment and may interfere with compliance to this intervention. Therefore, confirming that taste deficits are present in CKD will improve our understanding of how taste deficits can affect intake, and inform dietary counselling in the future. A systematic review was conducted. Studies that included adults with CKD and healthy controls, and assessed salt taste sensitivity, perceived intensity, and/or hedonic ratings were included. Study quality was assessed using the Academy of Nutrition and Dietetics Evidence Analysis Library Quality Criteria Checklist: Primary Research. Of the 16 studies, the majority reported decreased salt taste sensitivity, but no consistent differences in intensity or hedonic ratings were observed. Higher recognition thresholds in CKD patients were associated with higher sodium intake, but results should be interpreted with caution as the measures used were subject to error in this population. In conclusion, salt taste sensitivity is decreased in CKD, but intensity and hedonic evaluations appear to be more robust. Given that hedonic assessments are better predictors of intake, and that salt taste preferences can be changed over time, dietary counselling for low-sodium intake is likely to be effective for this population.

Aversion to a High Salt Taste is Disturbed in Patients With CKD

“…Taste impairment is common in patients with CKD and its causes include aging, uremia, neuropathy in patients with diabetes mellitus, medications, a low serum zinc concentration, and impaired oral health. 17 , 23 , 26 Uremic toxins in saliva have been suggested to damage taste cells in patients with CKD. 38 …”

“…They were asked whether they tasted anything; if they replied affirmatively, they were asked the taste type and whether they disliked the taste or not. We asked the “dislike or not” question because, in contrast to taste preference tests using foods or beverages, 17 , 29 , 30 we predicted that few people would “like” flavored filter paper; therefore, we decided to ask “dislike or not” instead of “like or not”. We defined the detection threshold for the lowest concentration sensed when participants tasted the reagents as the recognition threshold for the concentration that may be perceived as the taste type (salt, sweet, sour, and bitter tastes) and the aversion threshold as the concentration that was initially unpleasant.…”

“…Based on these findings, salt intake in mammals is assumed to be affected by the appetitive-aversive balance, for example, for low salt concentrations (accelerator) and the avoidance of high salt concentrations (decelerator). Most of the taste tests previously conducted on humans analyzed salt taste recognition or preferences under specific disease conditions 17 ; however, not many quantitatively examined aversive responses to a high concentration of salt. 18 To elucidate the aversive behavior of salt, it is necessary to study not only the salt taste, but also its interactions with other tastes.…”

“…In the present study, we attempted to quantitatively evaluate aversive behavior to high salt concentrations in healthy subjects by adding the concepts of the preference for and aversion to salt. Moreover, because taste disorders are common in patients with CKD, 17 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 we performed taste tests on patients with CKD.…”