Association between 6-n-propylthiouracil (PROP) bitterness and colonic neoplasms

Dig Dis Sci. 2005 Mar;50(3):483-9. doi: 10.1007/s10620-005-2462-7.


Inadequate vegetable intake appears to increase colon cancer risk. Since genetic variation in taste influences vegetable preference, we tested associations between bitterness of 6-n-propylthiouracil (PROP), a measure of taste genetics, and number of colonic polyps, a measure of colon cancer risk, in 251 men who underwent screening lower endoscopy. Patients used the general Labeled Magnitude Scale to rate bitterness of 1.6 mg PROP delivered via filter paper. A subset of 86 patients reported weekly vegetable intakes, excluding salad or potatoes. PROP bitterness correlated significantly with polyp number, an effect separate from age-associated increases in polyp number. The PROP-polyp relationship was strongest in men over 66 years, and older men with polyps were most likely to be overweight or obese. In the subset reporting vegetable intake, men who tasted PROP as more bitter consumed fewer vegetables. These preliminary findings suggest that taste genetics may influence colon cancer risk, possibly through intake of vegetables.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Age Distribution
  • Aged
  • Aged, 80 and over
  • Chi-Square Distribution
  • Cohort Studies
  • Colonic Neoplasms / epidemiology
  • Colonic Neoplasms / genetics*
  • Colonic Neoplasms / pathology
  • Colonic Polyps / epidemiology
  • Colonic Polyps / genetics*
  • Colonic Polyps / pathology
  • Diet*
  • Feeding Behavior
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Probability
  • Prognosis
  • Risk Assessment
  • Sensitivity and Specificity
  • Sigmoidoscopy
  • Survival Rate
  • Taste / genetics*
  • Taste Threshold
  • Uracil / analogs & derivatives*
  • Uracil / metabolism*
  • Vegetables*


  • 6-n-propyluracil
  • Uracil