Abstract

The precise orosensory inputs engaged for dietary lipids detection in people are unknown. We evaluated whether a common SNP (rs1761667) in the CD36 gene that reduces CD36 expression and the addition of orlistat, a lipase inhibitor, to reduce fatty acids (FA) release from triacylglycerols (TG), the main component of dietary fats, would attenuate fat orosensory sensitivity in humans. Twenty one obese subjects with different rs1761667 genotypes (6 AA, 7 AG and 8 GG) were studied on two occasions in which oleic acid and triolein orosensory detection thresholds were measured using emulsions prepared with and without orlistat. Subjects homozygous for the G-allele had 8 fold lower oral detection thresholds for oleic acid and triolein than subjects homozygous for the A allele, which associates with lower CD36 expression (P=0.03). Thresholds for heterozygous subjects were intermediate. Addition of orlistat increased detection thresholds to triolein (log threshold = -0.3 ± 0.2 vs. 0.3±0.1; p<0.001) but not oleic acid (log threshold= -1.0±0.2 vs. -0.8±0.2; p>0.2). In conclusion, this is the first experimental evidence for a role of CD36 in fat gustatory perception in humans. The data also support involvement of lingual lipase and are consistent with the concept that FA and not TG is the sensed stimulus.