The Association Between Olfaction and Taste Functions with Serum Ghrelin and Leptin Levels in Obese Women.

To investigate the olfaction and taste functions in obese female patients and the association between serum ghrelin and leptin levels compared with healthy controls. Fifty-two obese women, who have a body mass index >30 kg/m, and 15 healthy women were included in the study. After 8 hrs fasting, blood samples were taken for serum biochemical parameters, ghrelin, and leptin level measurement. For the quantitative assessment of olfactory function, all participants underwent an N-butanol threshold test and odor identification test using 12 Sniffin' Sticks fragrance sticks. The gustatory function was tested by administering a whole-mouth above threshold test using sucrose solutions. The sucrose taste threshold score in obese women was significantly higher than the controls ( = 0.004). We found positively significant correlation between serum ghrelin levels and n-butanol threshold scores in obese women ( = 0.300,  = 0.031). N-butanol smell threshold was not significantly different between the two groups ( = 0.149), while the Sniffin' Sticks smell test scores were significantly lower in obese women compared with the controls ( = 0.007). Serum leptin levels were also significantly higher in obese women ( < 0.001) although there was no significant difference in serum ghrelin levels between the two groups ( = 0.768). There was no correlation between serum leptin levels and Sniffin' Sticks scores, n-butanol, and sucrose taste threshold scores in obese women. These results might suggest that leptin, which is an anorexigenic peptide, may have a negative effect on taste and smell functions. More studies are warranted to elucidate the exact role of ghrelin secretion on olfaction and taste functions.