Studying the relationship between taste thresholds and blood glucose in patients with severe obesity: new insights for the management and improvement of comorbidities in obesity?

Obesity is now considered a multifactorial disease, where various metabolic, functional, and socio-environmental components contribute to the development of the disease. Despite extensive research in obesity disease, comprehensive studies examining taste perception and its association with obesity remain scarce. Researchers have suggested that there may be taste alterations in patients with obesity, suggesting that an increase in BMI is associated with a decrease in taste perception (i.e., an increase in sensory thresholds). It is still not clear whether is the state of obesity that leads to a change in taste thresholds or vice versa. Moreover, it remains unclear whether there is a relationship and causal link between taste thresholds for sweet and blood glucose levels. The sense of taste, especially sweet taste, is linked to brain-reward processes which drive eating behavior, food choices and consumption. The aim of this work is to investigate, in a sample of obese subjects, the relationship between sweet taste thresholds and blood levels of glucose and glycated hemoglobin. Methods: A sample of 103 severe obese subjects were recruited. An ISO13301:2018 (E) methodology (3-Alternative-Forced-Choice, 3-AFC), was used to determine subjects’ sweet taste thresholds. Results: results showed that the sweet taste threshold correlated positively with the blood glucose concentrations (mg/dL) of the study sample (R= 0.203 p< 0.05). This means that subjects with higher sweet taste thresholds (lower sensitivity) also have higher blood concentrations of glucose. Accordingly, plasma concentrations of glycated hemoglobin correlated positively with sweet taste thresholds (R= 0.23 p< 0.05). Finally, there was a positive correlation between taste thresholds and blood levels of triglycerides (R= 0.32 p< 0.05). Discussion: these data, although preliminary, can be considered an insight into the relationship between taste thresholds and certain blood parameters. Further studies could highlight whether taste thresholds could be considered as a predictor of prediabetes, impaired fasting blood glucose or dietary diabetes. It also could be a modifiable factor on which to intervene on nutritional rehabilitation in severe obesity.