In the second story today on the role played by genes on health and risk of disease, the Fred Hutchinson Cancer Research Center is seeking volunteers for a study, called DIGEST (Dietary Influences on Glucuronidation), to see how the interplay of genes and diet - in particular, a diet rich in specific plant compounds - may affect the function of the body's detoxifying machinery.
The researchers said that previous studies have shown that compounds in certain fruits and vegetables can increase the activity of detoxifying enzymes that help rid the body of potentially harmful substances, including carcinogens. Genetic differences among individuals can play a role in how effectively these cancer-fighting enzymes work.
The results of this study, funded by the US National Cancer Institute, could be important in making recommendations about diets that prevent cancer, according to the organisers.
Researchers are currently looking for around 300 people, aged 20 to 40, for the first half of this two-part study. Participants will provide blood, urine and saliva samples, fill out dietary and health questionnaires and keep a food diary. They also will take acetaminophen (Tylenol) and aspirin (enzyme activity is measured by looking at the breakdown of these drugs).
Of those initially enrolled, 60 will be asked to participate in the second phase, a 28-day feeding study. Eligibility to participate in this phase will depend on the participants' genetic pattern of metabolic enzymes as determined by DNA analysis of a blood sample.
The feeding study, conducted in two 14-day sessions, will look at the influence of a diet high in fruits and vegetables on the function of metabolizing enzymes. Participants will eat dinner at the Hutchinson Center and take home breakfast, lunch and snacks. They will also provide blood and urine samples, take aspirin and Tylenol, keep a physical-activity record and be weighed several times. Women must track their menstrual cycles.