Genetic Sensitivity to 6- n-Propylthiouracil Has No Influence on Dietary Patterns, Body Mass Indexes, or Plasma Lipid Profiles of Women

Abstract

Background Genetic sensitivity to the bitter taste of 6- n-propylthiouracil (PROP) has been reported to determine preferences for bitter, sweet, and fat-containing foods, affect dietary habits, influence body weight, and modify chronic disease risk. Objective To examine associations between PROP responsiveness, food choices, dietary intakes, and plasma chemistries in a clinical sample of adult women. Subjects/design This nested case-control study was based on female breast cancer patients (n=179) and cancer-free controls (n=179). Main outcome measures Taste responsiveness measure was based on a 25:50:25 split of summed bitterness ratings of five PROP solutions. Food preferences were based on a 171-item checklist. Food and nutrient intakes were assessed using a food frequency questionnaire. Heights and weights were measured and plasma cholesterol and triglyceride levels were obtained. Results High PROP response was unrelated to reported preferences for sweet or high-fat foods. PROP responsiveness was unrelated to the reported frequency of food use, or to macronutrient composition of the diet. In regression models, PROP responsiveness had no influence on percent of dietary fat, body mass index, or plasma cholesterol, after adjusting for covariates. Conclusions In this study PROP responsiveness was not associated with diets lower in sugar and fat, more favorable plasma lipid profiles, or with lower body mass indexes. The study provided no evidence to suggest that genetic PROP taster status had a measurable influence on health outcomes. The clinical utility of PROP taster screening is not supported by these study results.