Evidence supporting oral sensitivity to complex carbohydrates independent of sweet taste sensitivity in humans

Abstract

Compared to simple sugars, complex carbohydrates have been assumed invisible to taste. However, two recent studies proposed that there may be a perceivable taste quality elicited by complex carbohydrates independent of sweet taste. There is precedent with behavioural studies demonstrating that rats are very attracted to complex carbohydrates, and that complex carbohydrates are preferred to simple sugars at low concentrations. This suggests that rats may have independent taste sensors for simple sugars and complex carbohydrates. The aim of this paper is to investigate oral sensitivities of two different classes of complex carbohydrates (a soluble digestible and a soluble non-digestible complex carbohydrate), and to compare these to other caloric and non-nutritive sweeteners in addition to the prototypical tastes using two commonly used psychophysical measures. There were strong correlations between the detection thresholds and mean intensity ratings for complex carbohydrates (maltodextrin, oligofructose) (r = 0.94, P < 0.001). There were no significant correlations between the detection thresholds of the complex carbohydrates (maltodextrin, oligofructose) and the sweeteners (glucose, fructose, sucralose, Rebaudioside A, erythritol) (all P > 0.05). However, moderate correlations were observed between perceived intensities of complex carbohydrates and sweeteners (r = 0.48–0.61, P < 0.05). These data provide evidence that complex carbohydrates can be sensed in the oral cavity over a range of concentrations independent of sweet taste sensitivity at low concentrations, but with partial overlap with sweet taste intensity at higher concentrations.

The Associations Between Oral Complex Carbohydrate Sensitivity, BMI, Liking, and Consumption of Complex Carbohydrate Based Foods

“…In this study, Low et al. () reported high retest correlations for measures of oral complex carbohydrate sensitivity.…”

“…Our recent research provides support for this proposition as we have established significant differences in oral complex carbohydrate sensitivity (maltodextrin, oligofructose) among 32 participants with smaller and larger waist circumference measurements (Low et al., ). That is, more sensitive participants or those who experienced high intensity towards both complex carbohydrates (maltodextrin, oligofructose) had on average more than 10 cm differences in terms of waist circumference measurements in comparison to less sensitive participants or those who experienced low intensity (Low et al., , ). These differences were, however, not found for BMI measurements (Low et al., , ), suggesting that oral sensitivity towards complex carbohydrate (maltodextrin) is associated with excess intra‐abdominal fat mass specifically but not weight and height measurements.…”

“…That is, more sensitive participants or those who experienced high intensity towards both complex carbohydrates (maltodextrin, oligofructose) had on average more than 10 cm differences in terms of waist circumference measurements in comparison to less sensitive participants or those who experienced low intensity (Low et al, 2017a(Low et al, , 2017b). These differences were, however, not found for BMI measurements (Low et al, 2017a(Low et al, , 2017b, suggesting that oral sensitivity towards complex carbohydrate (maltodextrin) is associated with excess intra-abdominal fat mass specifically but not weight and height measurements. Although BMI measurements are widely used for the evaluation of obesity both in adults (Krauss, Winston, Fletcher, & Grundy, 1998;Rosenbaum et al, 1997), and children (Barlow, Dietz, Klish, & Trowbridge, 2002;Savva et al, 2000), body fat distribution and abdominal fat mass can vary substantially across populations and can differ greatly within a narrow range of BMI (WHO, 2008).…”

“…Finally, there is a lack of test‐retest data for taste function and liking measures in this study. However, in one recently published work on evidence supporting oral sensitivity to complex carbohydrates in humans, oral complex carbohydrate sensitivity thresholds were measured for up to seven times for each participant (repeated measures; Low et al., ). In this study, Low et al.…”

“…It is widely believed that the human taste system consists of five basic tastes: sweet, sour, salty, bitter, umami, and much recent evidence supports a sixth taste responsive for fatty acids (Chalé‐Rush, Burgess, & Mattes, ; Mattes, , ; Newman, Haryono, & Keast, ; Newman, Bolhuis, Torres, & Keast, ; Newman & Keast, ; Running, Craig, & Mattes, ; Stewart & Keast, ; Stewart et al., ; Stewart, Feinle‐Bisset, & Keast, ; Tucker, Edlinger, Craig, & Mattes, ). More recent psychophysical studies suggest that humans may perceive complex carbohydrates, independent of sweet taste (Lapis, Penner, Balto, & Lim, ; Lapis, Penner, & Lim, , ; Low, Lacy, McBride, & Keast, ). That is, sensitivity of simple carbohydrates (glucose and sucrose) were significantly correlated with each other, but not with sensitivity of complex carbohydrates (Lapis et al., , ).…”