Olfactory and gustatory functions and its relation to body weight.

In the present study we investigated the influence of body weight as defined by BMI on gustatory and olfactory perception. A total of 66 healthy adults (41 females; 25 males) participated in psychophysical measurements using the "Sniffin' Sticks" test and "Taste Strips" test. Odor thresholds as well as discrimination and identification performance were determined. Tests of gustatory function involved the identification and thresholds of sweet, sour, salty, or bitter taste. In this study, all subjects were healthy participants in a middle age range (between 20 and 56 years of age). Persons with an extreme BMI value were excluded. Subjects were classified according to their BMI in four groups: (1) 15-19.9 kg/m, (2) 20-24.9 kg/m, (3) 25-29.9 kg/m, and (4) >30 kg/m. We did not observe an overall effect of BMI on general sensory sensitivity. There was a significant influence of BMI on olfactory thresholds (F(3,62)=2.79; p<0.047) which increased with increasing BMI. In a similar line, the gustatory thresholds for "salty" were significantly higher with higher BMI (F(3,62)=3.06; p<0.035). Olfactory discrimination and identification was not affected by BMI. Thresholds for odor and sweet or salty taste were also correlated. Our data show that body weight influences gustatory and olfactory perception in healthy adults. Increasing BMI is associated with a decrease in olfactory and taste sensitivity. These findings may have implications for the understanding of pathophysiological mechanisms in patients.