Progress 12/01/00 to 09/30/04
Outputs
The objective of this project is to link genetic variation in bitter taste perception to food preferences, dietary habits and body weight. Studies have shown that those who are taste blind to 6-n-propylthiouracil (i.e., non-tasters) are less sensitive to the oral sensation of fat among other taste qualities. Non-tasters have been shown to prefer higher fat foods and to have higher body weights than tasters. Thus, using PROP as a screening tool, we can identify individuals who may be at risk for excess weight gain due to dietary causes. Studies conducted during the course of this project have examined this relationship in different age groups including preschool children, young adults and middle-aged adults. In a recent study, 40 overweight, middle-aged women were recruited from the local community. They were classified as non-tasters (n=8), medium tasters (n=18) or super-tasters (n=14) of PROP using a filter paper screening procedure. Anthropometric measures included,
height, weight, body fatness (biological impedance analysis), triceps skinfold thickness and waist circumference. Dietary restraint and disinhibition were also measured to assess cognitions associated with body weight. Resulls showed that BMI was 6.2 units higher in non-taster women as compared to super-taster women (29.7 + 0.9 vs. 23.5 + 0.9, respectively; p<0.05). Body fatness (p<0.01) and triceps skinfold thickness (p< 0.05) were also higher in these women. Waist circumference showed a trend in the appropriate direction. Although disinhibition (emotional overeating)was associated with greater adiposity, the relation between PROP status and adiposity was not altered after controlling for disinhibition. These data suggest that the PROP non-taster phenotype was strongly associated with several measures of adiposity in middle-aged women including BMI, overall body fatness and triceps skinfold. These data confirm our previous findings and suggest that the PROP polymorphism may be a
reliable indicator of weight gain susceptibility.
Impacts
Current findings suggest that genetic taste differences (as measured by taste sensitivity to the bitterness of 6-n-propylthiouracil) play a role in the development of eating patterns in children and may make an important contribution to differences in adiposity later in life. PROP status may help to predict those who may be at risk for excess weight gain and obesity.
Publications
- Ullrich NV, Touger-Decker R. O Sullivan Maillot J, Tepper BJ. PROP taster status and self-perceived food adventurousness influence food preferences. Journal of the American Dietetic Association, 2004; 104:543-549.
- Keller KL, Tepper BJ. Inherited taste sensitivity to 6-n-propylthiouracil and diet and body weight in children. Obesity Research, 2004; 12:904-912.
- Kirkmeyer SV, Tepper BJ. Consumer reactions to creaminess in dairy products and genetic taste sensitivity to 6-n-propylthiouracil: A multidimensional study. Food Quality & Preference, 2004, in press.
- Goldstein GL, Daun H, Tepper BJ. Adiposity in middle-aged women associates with genetic taste blindness to 6-n-Propylthiouracil. Obesity Research, 2004, in press.
|
Progress 01/01/03 to 12/31/03
Outputs
The objective of this project is to link genetic variation in bitter taste perception to food preferences, dietary habits and body weight. Studies have shown that those who are taste blind to 6-n-propylthiouracil (i.e., non-tasters) are less sensitive to the oral sensation of fat among other taste qualities. Non-tasters have been shown to prefer higher fat foods and to have higher body weights than tasters. Thus, using PROP as a screening tool, we can identify individuals who may be at risk for excess weight gain due to dietary causes. Studies conducted during the course of this project have confirmed this relationship in different age groups including preschool children, young adults and middle-aged adults. Current studies are investigating the influence of PROP taster status and maternal variables on food intake and body weight parameters in 7-11 yr. old children. Variables of interest include: PROP taster status; adiposity measures; maternal dietary restraint
(conscious control of eating) and disinhibition (loss of control over eating); and child feeding attitudes and practices. Children also completed 3-day food records to assess habitual dietary intakes. Non-taster children consumed more daily energy than medium taster or super-taster children (p<0.01). Daughters of disinhibited mothers also consumed more daily energy than daughters of mothers who were not disinhibited (p<0.01). These data suggest that PROP taster status, gender, and maternal disinhibition play a role in the development of eating habits of children. However, these differences in energy consumption could not be linked to variations in macronutrient intake. PROP taster groups did not vary in %BMI-for-age, but children in this sample were in the normal weight range (<85th percentile). Regression analysis revealed that %BMI-for-age in children was a function of maternal BMI, and several child feeding practices including concern about child weight, pressure to eat and food
restriction (all positive predictors in the model). Maternal restraint had a marginal influence on % BMI-for-age, in the negative direction. The adjusted R2 of the model was 0.59. PROP status was not a significant predictor of adiposity in these children. Nevertheless, PROP status had a robust effect on adiposity of the mothers. Non-taster mothers had higher BMI, % body fatness and triceps skinfold thickness than super-taster mothers (<0.001). BMI was 6.2 units higher in non-taster mothers as compared to super-taster mothers. Together these data suggest that current energy intakes were higher in non-taster children than taster children, but differences in adiposity were not evident at this time. Our findings in mothers strongly suggest that PROP-related adiposity differences are likely to appear in these children later in their development. Follow-up studies in these children will investigate this possibility.
Impacts
Current findings suggest that genetic taste differences (as measured by taste sensitivity to the bitterness of 6-n-propylthiouracil) play a role in the development of eating patterns in children and may make an important contribution to differences in adiposity later in life. PROP status may help to predict those who may be at risk for excess weight gain and obesity.
Publications
- Zhao L, Kirkmeyer SV, Tepper BJ. A paper test for assessing genetic taste sensitivity to 6-n-propylthiouracil. Physiology & Behavior, 2003; 78:625-633.
- Kirkmeyer SV, Tepper BJ. Understanding creaminess perception in dairy products using free-choice profiling and genetic responsivity to 6-n-propylthiouracil (PROP). Chemical Senses, 2003; 28:527-536.
- Tepper BJ, Keller KL, Ullrich NV. Genetic taste markers and preferences for bitter and pungent foods. In: Challenges in Taste Chemistry and Biology. American Chemical Society Symposium Series 867, Hofmann, T, Pickenhagen W, Ho C-T (eds.), pp. 60-74, 2003.
|
Progress 01/01/02 to 12/31/02
Outputs
The data collected in this project provide evidence that genetic differences in taste as determined by 6-n-propylthiouracil (PROP) screening are associated with differences in food preferences and body weight in both adults and children. Individuals who are PROP non-tasters have higher fat intake and body weights than those who are PROP sensitive.
Impacts
Results from this project show that the inherited ability to taste the bitter compound 6-n-propylthiouracil (PROP) serves as a genetic taste marker for fat intake and body weight. Screening for PROP status may be useful in epidemiological studies as a predictive marker for obesity, and other chronic diseases such as heart disease and cancer.
Publications
- No publications reported this period
|
Progress 01/01/01 to 12/31/01
Outputs
The ability taste bitter, thiourea compounds such as phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) is an inherited trait. About 70% of the U.S. population is sensitive to the bitterness of PTC and PROP (they are called 'tasters'); the remaining individuals perceive PTC/PROP as weak or tasteless and are called 'non-tasters'. PROP tasters can be further divided into medium tasters and super tasters, with the latter group being the most sensitive to PROP bitterness. Results of our earlier work showed that PROP tasters (medium and super tasters) were more sensitive to the texture of fat in salad dressing. Although tasters perceived more fattiness in a 40% fat vs. a 10% fat salad dressing, they showed no preference for either sample. Non-tasters could not distinguish between the two samples but preferred the 40% fat sample. Among young, adult males, those who were non-tasters also maintained slightly higher body mass indices than those who were tasters. Based
on these data, we hypothesized that taste blindness to PROP might be a marker for individual differences in fat preference and fat intake, dietary behaviors that ultimately influence body weight. Current studies are investigating the association between PROP status and body weight in women who have been characterized by dietary restraint (conscious control of eating) and disinhibition (emotional overeating). By including these variables we hope to tease out the separate effects of genetic taste background and cognitive factors on body weight in women. Thus far, studies investigating associations among PROP status, taste and body weight have been small in scale, typically involving 75-200 subjects. In order to better understand these relationships, much larger population-based studies are needed. To that end, two brief screening methods were developed for classifying individuals by PROP taster status. The two methods are modifications of a commonly-used, suprathreshold procedure. Adult
subjects rated the perceived intensity of solutions of 0.032, 0.32, and 3.2 mmol/L PROP and 0.01, 0.1, 1.0 mol/L NaCl (3-solution test) as well as solutions of 0.32 mmol/L PROP and 1.0 mol/L NaCl (1-solution test) using the Labeled Magnitude Scale (LMS). Subjects were classified as PROP non-tasters, medium tasters, or super-tasters by the 3-solution test. Taster status was independently determined by the 1-solution test using numerical cutoff scores, which were determined by calculating the +95% confidence interval around the group means for PROP taste intensity. Super-tasters gave PROP a rating of >51 ('very strong' on the LMS) and nontasters gave PROP a rating of <15.5 (approximately 'moderate' on the LMS). Medium tasters fell between these two limits. 91% of nontasters, 82% of medium tasters and 89% of super-tasters were classified in a similar way by the two methods. Agreement between methods was high [Coefficient of association (P)=0.74; p<0.001]. These data suggest that 3- and
1-solution methods can reliably classify subjects by taste sensitivity to PROP. The procedures are quick and easy to administer and will be extremely useful for screening subjects in future studies in this project.
Impacts
The methods described here will permit PROP screening to be utilized in a wide range of scientific and technical applications including studies on human perception, consumer acceptance and epidemiological and health outcomes.
Publications
- Tepper BJ, Christensen CM, Cao J. Development of brief methods to classify individuals by PROP taster status. Physiology & Behavior, 2001;73;571-77.
|
|