General Decrease of Taste Sensitivity Is Related to Increase of BMI: A Simple Method to Monitor Eating Behavior

Abstract

Background and Objectives. The present study was conducted to evaluate the relationship between taste identification ability and body mass index (BMI) by studying the response to the administration of different taste stimuli to both sides of the tongue in three different groups of subjects. Subjects and Methods. Thirty healthy normal-weight volunteers, 19 healthy overweight subjects, and 22 obese subjects were enrolled. For each subject, the lateralization Oldfield score, body weight, height, and blood pressure were determined. The taste test is based on filter paper strips soaked with 4 taste stimuli presented at different concentrations to evoke 4 basic taste qualities (salty, sour, sweet, and bitter); pure rapeseed oil and water were also administered to evoke fat and neutral taste qualities. The stimuli were applied to each side of the protruded tongue. Subjects were asked to identify the taste from a list of eight descriptions according to a multiple choice paradigm. Results. The results showed a general lowering of taste sensitivity with the increase of BMI, except for the taste of fat with rapeseed oil as the stimulus. Other variables affecting taste sensitivity are age (negative association), gender (women generally show higher sensitivity), and taste stimuli concentration (positive association). Conclusions. Our findings could provide important insights into how new therapies could be designed for weight loss and long-term weight maintenance and how diets could be planned combining the correct caloric and nutritional supply with individual taste preferences.

A Study on the Relationship between Type 2 Diabetes and Taste Function in Patients with Good Glycemic Control

“…While we previously identified some gender-related differences in taste function among healthy and diseased individuals [15,27], in the present study, we did not show any significant effect of gender on the differences in taste function between healthy subjects and T2DM patients.…”

“…The taste test, performed at the Diabetology Unit, was based on filter paper strips [14], modified as described in our previous work [15]: cotton pads, soaked with four substances (sodium chloride, citric acid, sucrose, and quinine hydrochloride) were applied to the protruded tongue, immediately posterior to its first third, either to the left or right side, in order to study lateralization too; each basic taste quality (salty, sour, sweet, and bitter) was presented at 4 different concentrations (Table 1); in addition, pure rapeseed oil and water were administered to evoke fat and neutral taste, respectively. Rapeseed oil is a neutral oil which has a pale yellow color and is almost odorless; rapeseed oil was chosen instead of olive oil since the latter has a specific texture and increased volatility in the oral cavity, making it easily recognizable.…”

Taste Responses in the Nucleus of the Solitary Tract of Awake Obese Rats Are Blunted Compared With Those in Lean Rats

“…Collectively, these data suggest that the shorter duration of taste responses in obese subjects, both rodents (present data), and humans (Hardikar et al, 2018) might underlie the lower hedonic responses to palatable taste stimuli in overweight subjects that have been reported previously (Bartoshuk et al, 2006). In addition, lower taste sensitivity has been reported to correlate with a higher basal metabolic index (Overberg et al, 2012; Vignini et al, 2019).…”

Extra-oral bitter taste receptors: New targets against obesity?

“…At least in human fungiform taste papillae, a recent RNA-seq study showed that the expression of type II taste-related genes, including α-gustducin and hTAS2R31, was reduced in obese subjects compared to the lean group [61]. This may result in the reduced sensitivity to bitter taste observed in obese subjects and may affect food choices [61][62][63][64][65][66].…”