GENETIC AND BIOBEHAVIORAL MARKERS OF DIETARY COMPLIANCE

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Increased risk of breast cancer in women has been associated with increased consumption of fats and inadequate consumption of vegetables and fruits. Dietary guidelines aimed at cancer prevention recommend a reduced-fat diet and/or the consumption of at least five servings of fruits and vegetables per day (5-A-Day program). However, dietary behaviors tend to be firmly established, and little is known about barriers to dietary change and the predictors of compliance with dietary cancer prevention regimes. We have identified two separate taste markers that may be associated with differential consumption of vegetables and fats, respectively. The first marker is the genetically-mediated sensitivity to the bitter taste of n-propylthiouracil (PROP). In past studies, the rejection of bitter-tasting foods, notably cruciferous vegetables, has been linked to PROP taster status. Our hypothesis is that PROP "supertasters" will be characterized by a habitually low vegetable consumption, and will prove resistant to the 5-A-Day diet plan. The second taste marker is the sensory preference profile for sugar/fat mixtures. Response to sweetened dairy products in a model system is thought to predict preferences for dairy fats, a major source of saturated fat in women. If the two factors can be linked to consumption patterns, they may serve as markers of dietary exposure to substances that alter cancer risk. We will therefore examine taste marker status and fat and carotenoid intakes in patients undergoing breast biopsy procedure. Dietary intake assessment will employ an FFQ instrument and 4 days of telephone-administered 24-hr recalls. Preferences for vegetables and high-fat foods will be established using a questionnaire instrument. The study will further link carotenoid intakes with plasma and tissue carotenoid levels (obtained under IRPU-2), and examine their impact on the expression of estrogen receptors and gap-junction proteins (IRPG-4 and IRPG-5). This project will also monitor compliance with a diet based on the 5-A-Day program and supplemented with 30 mg/day beta-carotene. We hypothesize that PROP taster status and fat preference profiles will predict dietary compliance, serving as genetic and biobehavioral markers of success or failure in dietary cancer prevention.