PTC/PROP tasting: anatomy, psychophysics, and sex effects

Area of Science:

• Genetics
• Human Physiology
• Sensory Science

Background:

• Individual differences in taste perception, particularly for phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP), influence dietary behaviors.
• Early studies suggested variations in taste perception, but lacked modern statistical rigor and detailed classification.

Purpose of the Study:

• To re-evaluate early phenylthiocarbamide (PTC) tasting studies using contemporary statistical methods.
• To investigate the characteristics of 6-n-propylthiouracil (PROP) supertasters, including their sensory perception and anatomical correlates.
• To examine sex differences in taste perception and the underlying anatomical basis.

Main Methods:

• Statistical re-analysis of historical PTC tasting data.
• Sensory scaling of PROP bitterness to identify supertasters.
• Psychophysical testing of supertasters' perception of various tastes and oral irritants.
• Anatomical analysis of fungiform papillae and taste bud density in relation to taste perception.

Main Results:

• Modern statistical analysis confirmed a higher frequency of women tasting PTC and being classified as tasters.
• Identification of supertasters who perceive PROP as intensely bitter and exhibit heightened sensitivity to other bitter, sweet, and oral irritant stimuli.
• Significant correlation between fungiform papilla and taste bud density and PROP bitterness perception, supporting the supertaster concept.
• Women were found to be supertasters more frequently, with greater fungiform papillae and taste bud density.

Conclusions:

• Sex differences exist in PTC and PROP taste perception, with women more frequently exhibiting supertaster phenotypes.
• Taste receptor density in fungiform papillae is a significant anatomical correlate of PROP bitterness perception.
• Future research on taste perception and food behavior should incorporate supertaster identification and analysis of sex effects.