View clinical trials related to Diet.
Filter by:This study will examine the risks and protective effects of dietary factors on temporary genetic damage to cells lining the gastrointestinal tract and to blood cells. Some foods, including very well done meat, may increase genetic damage in cells, while others, such as yogurt and vegetables, may reduce genetic damage. This study may provide new information on the influence of diet on increasing or decreasing the risk of developing cancer, particularly colorectal cancer. The study is conducted at the General Clinical Research Center (GCRC) of the University of North Carolina. Nonsmoking, English-speaking, healthy adults between 18 and 45 years of age may be eligible for this 4-week study. Participants undergo the following tests and procedures: - Interview: Participants complete questionnaires including information on their diets, habits, past and present health, and family histories. - Diet: Participants adhere strictly to the diet provided by the dietician at the GCRC for all 4 weeks of the study. All meals are provided by the GCRC. All meals contain well-done meat and some contain yogurt, cruciferous vegetables, including broccoli and cabbage, and chlorophyllin tablets. Chlorophyllin is a compound in some foods that protects against genetic damage. - Urine sampling: Participants collect a urine sample each morning except Saturday and Sunday. - Stool sampling: Participants collect two stool samples during the study, one during the second week and another during the fourth week. - Blood draw: About 2-1/2 tablespoons of blood are drawn once a week for research purposes. The blood is tested for the effects of eating foods in the different diets used in the study. - Rectal biopsies: Four pinch biopsies, each about the size of a grain of rice, are taken from the rectum once a week for research purposes. For this procedure, forceps are inserted shallowly into the rectum to collect the tissue. The effects of the different diets on the colon cells are measured.
This study will evaluate the structure of error in self-reporting instruments on diet, in following up the Observing Protein and Energy Nutrition Study (OPEN) conducted in 1999 and 2000. The OPEN study, the largest of its kind, resulted in a wealth of nutritional biomarker data-measurable indicators of changes in organisms at the level of molecules or cells. A biomarker could help in understanding how environment and disease are related and about disease risks. Furthermore, its findings showed that the relative estimates of disease risk may be weakened by a food frequency questionnaire and a 24-hour questionnaire. Scientists have long recognized that self-reported information from questionnaires and interviews contains errors, but there has been uncertainty about the structure of such errors. For the proposed study, a food record and a food checklist-adjusted food frequency questionnaire will be compared with the previously used questionnaires, to determine whether the newer study instruments present less chance of measurement error. The results may provide better tools for a study on nutritional epidemiology, that is, the incidence and other aspects of disease and nutrition. OPEN study participants will be invited for follow-up. Patients who completed the 1999-2000 study who are not currently pregnant or a liquid weight loss diet may be eligible for this study. The original study recruited men and women 40 to 69 years of age. A letter with summary results from the original OPEN study will be sent to each of the 482 participants. Both the Food Record and the food checklist, called the Daily Food List, are instruments to be given. The Food Record asks the participant to record all foods and beverages consumed. The Daily Food List asks respondents to write in to the number of times a limited number of food categories are consumed. In addition, respondents will be asked to complete the National Cancer Institute Diet History Questionnaire (DHQ), identical to the one that they completed in the original OPEN study, regarding the previous 12 months. Participants will randomly be assigned to one of two groups. All will receive four study mailings over a 3-month period: the DHQ, First 4-Day Food Record (4-day FR), Second 4-day FR, and Booklet of 7-Day Food Lists (7-day FL), the latter listing selected foods that the participants will mark if consumed on the reporting day. Study Group A will receive the DHQ, first 4-day FR, second 4-day FR, and 7-day FL. Study Group B will receive the DHQ, 7-day FL, first 4-day FR, and second 4-day FR. Within 10 days after receiving the DHQ, participants will be called to schedule an appointment for a 30- to 45-minute visit. Participants will undergo the following procedures: - Complete the Physical Activity Questionnaire (by telephone for those who have moved out of the local area or are unable to attend the visit) - Have weight measured - Be asked about whether he or she has recently developed certain medical conditions, experienced dramatic changes in diet, or gained special education in nutrition The completion time for each instrument in dietary assessment is approximately as follows: - DHQ-60 minutes. - Each 4-day FR-80 minutes (20 minutes a day). - 7-day FL-35 to 49 minutes (5 to 7 minutes a day).
The primary objective of the Poly Prevention Trial (PPT) is to determine whether a low fat, high fiber, high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel. Secondary objectives of the PPT include 1) evaluating the effectiveness of the intervention program with respect to participant achievement of dietary goals; 2) examining the relation of dietary change and biochemical markers in blood; and 3) assessing the impact of the intervention on quality of life indicators.
This study, sponsored by the National Cancer Institute and Penn State University, will examine how a diet high in legumes (dried beans) influences risk factors for colon cancer and polyps. Many scientists believe that colon and rectal cancers develop from polyps (tumors of the lining of the large bowel). This study will test whether a high-legume diet can reduce levels of certain factors (blood insulin, blood glucose, and markers of inflammation such as C-reactive protein) that at elevated levels are known to increase the risk of colorectal polyps and colon cancer. Healthy men between 35 and 75 years of age may be eligible for this study, conducted at Penn State University in University Park, Pennsylvania. Candidates are screened with blood tests and measurements of height, weight, and blood pressure. All candidates must have had a colonoscopy within 2 years of entering the study. They may or may not have had adenomas and may or may not be insulin-resistant. Candidates must not have cancer, heart disease, kidney disease, diabetes, or other serious medical condition, and they must have no history of colorectal cancer, polyp removal, bowel surgery, polyposis syndrome, or inflammatory bowel disease. Participants undergo the following tests and procedures: - Caloric requirement testing: The subject's resting metabolic rate is measured while fasting and in the early morning at rest to determine daily calorie requirement before beginning the study diet. A special clear plastic hood is placed over the subject's head while his breathing is measured. He can communicate with the technician at all times during the 30-minute test. - Study diet: Subjects follow two required 4-week diets with a 3-week break in between, followed by an optional third 4-week diet. Subjects eat a healthy American diet for both of the required 4-week diet periods; about 1-1/2 cups of cooked legumes, such as pinto, baked, and navy beans are added to one of the two required diets. For the third (optional) diet period, subjects are given the same 1-1/2 cups of legumes, but are allowed to lose weight. Participants are given packages with all of the food they are to consume during the three diet periods. They may add up to five caffeine-containing beverages per day and up to two alcoholic drinks per week. They must eat all of the food they are given and only the food they are given. Subjects are expected to maintain a constant body weight during the two 4-week required diets, and their caloric intake may be increased or decreased as needed to maintain their screening weight. - Weight measurements: Subjects are weighed regularly at the clinic. - Blood samples: Subjects have blood samples drawn at the mid-point of each of the two required 4-week diets and at the beginning and end of each of the three 4-week diets. - Urine and stool samples: Urine and stool samples are collected at the beginning and end of the two required 4-week diets.
The investigators propose to conduct a randomized controlled trial at the patient level of the Telephone Linked Care - Behavioral Change (TLC-BC) system, which is designed to promote smoking cessation, reduce risky drinking, and improve physical activity and diet. They expect to: 1. successfully integrate an automated telephone behavior change intervention into primary care practices; 2. demonstrate improvement in health behaviors for individuals randomized (assigned by systematic chance) to use the TLC-BC system compared to individuals who receive written health education informational packets; and 3. evaluate the direct costs associated with the use and operation of the TLC-BC system. Project aims and hypotheses follow: Aim 1: Integrate a proven, totally automated computer telephone intervention, Telephone Linked Care - Behavior Change (TLC-BC), into primary care practices. This will be assessed by the patient and clinician/staff surveys at the end of data collection. Aim 2: Demonstrate an improvement in health behaviors for individuals randomized to use the TLC-BC system compared to individuals who receive written informational packets. Aim 3: Evaluate the direct costs associated with the use and operation of the TLC-BC system within the primary care setting. Hypothesis 1: The Telephone Linked Care - Behavioral Change system will be successfully implemented by patients and practices. Hypothesis 2: At 6 months a clinically significant improvement in behavioral change rates will be demonstrated for diet, physical activity, and smoking in the intervention group compared to patients in the control group. Hypothesis 3: At baseline, 3, 6, and 9 months risky drinking will be identified, but there will be no difference in improvement between the study groups.