This research study will compare participants on a diet rich in whole grains versus those on a typical American diet rich in refined grains, and determine the effects of these diets on intestinal health and immune response in adults, including those taking cholesterol-lowering drugs .
Men and women 40-65 years of age (women must be >1 yr post-menopausal or had both ovaries removed, if premenopausal)
Smoking or use of nicotine containing products in the last 6 months
BMI<20 or BMI>35kg/m2
Currently on a vegetarian diet
Not willing to be randomized to either the whole grains or refined grains group, or the negative control group
Length of Study
About 8 weeks
# of Visits
1 screening visit. If randomized to the whole grains and refined grains group, participants will be required to make up to 3 visits each week to the HNRCA over a period of about 8 weeks to pick up Center- prepared foods, as well as make additional visits for data and sample collections at the beginning and end of study. If randomized to the negative control group, participants will visit the HNRCA at the beginning and at the end of the study period to pick-up stool collection materials and deliver stool samples collected.
If randomized to the whole grains and refined grains group participants, consume the Center-provided study foods and beverages, which will consist of regular meals and snacks, exclusively for 8 weeks. If randomized to the negative control group, participants will consume own diet.
$25 for screening visit, and up to $1400 if you qualify and complete the study if randomized to the whole grains or refined grains group, and $200 if you qualify and complete study if randomized to the negative control group.
Can I work?
Please refer to the FREQUENTLY ASKED QUESTIONS section below, if you would like more information about the study. Or, if you prefer, please e-mail: firstname.lastname@example.org or call 1-800-738-7555; please refer to Study #2720.
FREQUENTLY ASKED QUESTIONS:
What is the purpose of this study?
Previous studies have suggested that whole grains can protect against obesity, diabetes, heart disease, and certain cancers. The purpose of this study is to determine the impact of consuming a diet rich in whole grains on immunity and gut health in adults.
What does participating in the study involve?
This study will compare the effects of whole grains and refined grains on your immune system and on the bacteria in your large intestine which may influence your immune system. To do this, we need to have 3 different groups in the study. Two of the three groups will be randomly assigned to a study diet (a diet containing either the whole grains or refined grains) and the other (control group) will continue following their normal diet. If you are assigned to one of the 2 diet groups you will receive a typical American diet for the first 2 weeks. After the second week, you will be assigned to either the whole grain group or the refined grain group for 6 weeks. The whole grain group will receive all their meals from the center and the grains will be whole grains (for example brown rice, whole wheat pasta, whole wheat bread). The refined grain group will also receive all their meals from the center and the grains will be refined grains (for example white rice, regular pasta, white bread). The control group will be asked to continue consuming their regular diet and no food will be provided to them by the center. The assignment to any of the 3 groups is random (like flipping a coin) and neither you nor the investigators have a choice as to which group you will be assigned to.
If you are assigned to the whole grain or refined grain group, you will be asked to consume only study foods and beverages for 8 weeks, visit the center 27 times, and do the following at week 2 and at week 8 of study:
1. complete several questionnaires
2. have your blood drawn on two consecutive days, collect 1 urine sample, and 1 saliva sample
3. collect all of the stool you produce over 3 consecutive days
4. come to the center up to 3 times per week to pick up study foods and beverages,
5. undergo an immune test on your skin (similar to a Tb test)
6. undergo measurements to determine your percent body fat and how many calories you burn at rest
If you are assigned to the control group, you will consume your regular diet throughout the 8-week study, and no food will be provided to you by the study. You will be asked to do the following at week 2 and at week 8 of study:
1. collect all of the stool that you produce for 3 consecutive days, and
2. have your body weight measured when you deliver your stool samples.
Where is the study located?
The study is being conducted at the Jean Mayer Human Nutrition Research Center on Aging (HNRCA) at Tufts University. We are located in downtown Boston at 711 Washington St. We are near the Tufts Medical Center T-stop on the Orange line, the Boylston St T-stop on the Green line, the South Station and Park St T-stops on the Red line, and the Tufts Medical Center T-stop on the Silver line.
Is there parking at the center?
There is metered parking on the surrounding streets and garage parking. We do not reimburse for parking and recommend taking public transportation if possible. However, if you park at the Tufts Medical Center garage (located at 274 Tremont Street), your parking ticket can be validated upon request for discounted parking by the security guard at the front desk in the HNRCA lobby.
Can I work during the study?
Yes you can. We will make every effort to coordinate the study schedule with your work schedule. However, you must be available to come to the center up to 3 times per week to pick up your meals and for other study-related activities if you are assigned to one of the 2 diet groups. If assigned to the control group you must come to the center to deliver your stool and have your weights measured according to the control study schedule.
What do I get for my time and participation?
You will receive a stipend for participating in the study. If you complete the entire study as a participant in one of the diet groups, the stipend is $1,200. You will also have all your foods and beverages provided for 8 weeks, so will save a lot in grocery money. If you complete the study as a participant in the control group, the stipend is $200, and no food will be provided to you.
How much time will the study take?
This study will take 8 consecutive weeks. If you are assigned to a diet group, most weeks you will visit the center up to 3 times per week for about 30 min per visit to pick up study foods and beverages, and get your weight measured. Duringweek 2 and week 8 of the study you will come to the center every weekday morning. During these 2 weeks you can expect to be at the center for 30 min to 2 hr depending on the activities for that day.
Can I choose which group I want to participate in?
No. You will be randomly assigned to a group. Like flipping a coin, neither you nor the research staff will get to choose which group you will be assigned to. You will not be able to switch to a different group.
If assigned to one of the diet groups, will I be able to eat my own food?
No. You will have to consume only the foods provided to you. The only exception is if you are assigned to the control group. In that case you will not receive food from the study, and will continue eating your regular diet.
If assigned to one of the diet groups, will I be able to substitute food items given to me for similar items that I like better?
No. If you choose to participate you must commit to consuming only the foods provided to you.
What kind of food do I have to eat?
The food is probably similar to your typical diet. Breakfast includes cereal, muffins, waffles, milk, juice, fruit and coffee or tea. Lunch includes sandwiches, pretzels, salads… Dinner includes pasta, burgers, vegetables…. Snacks are included as well.
What if I do not like the food?
We understand that everyone has different tastes. However, it is very important that everyone in the study eats only foods provided by the study. You will be ineligible to participate if you are not willing to eat foods provided by the study.
Do I really have to collect my stool?
Yes. This is a very important part of the study. We will provide you with all of the supplies you will need to collect, store and transport your stool. If you choose to participate in the study you are committing to collecting all of the stool you produce over 3 consecutive days during week 2 and week 8 of the study.
How do I bring my stool to the center?
We will provide you with a cooler, and clear instructions, to store and carry your stool samples.
Can I just collect stool at the center?
Yes, you can collect your stool at the center. However, you may not be at or near the center when nature calls, so you have to be willing to collect samples wherever you may be during your stool collection days.
Can I go on vacation while in the study?
If you participate in this study, you must plan your vacation around week 2 and week 8 of the study. A long weekend can usually be accommodated if arranged in advance. Other arrangements may also be possible if arranged ahead of time with study staff. Remember, it is important that you consume only study foods and beverages throughout the 8 week study period.
Can I smoke during the study?
No. Eligible participants must not have smoked or used any nicotine containing products 6 months prior to participating in the study nor during the 8 week study period.
Can I take diet supplements or vitamins while in the study?
No. You must agree to stop taking any supplements or vitamins you may be taking (except for calcium and vitamin D) 30 days prior to participating in the study and throughout the study as well. The study diets have been designed to provide the recommended amounts of all nutrients.
Will I lose/gain weight during the study?
To participate, you must be willing to maintain your current body weight throughout the duration of the study. We will closely monitor your weight during the study. We will change the amount of food we require you to eat if your weight increases or decreases to ensure maintenance of your body weight.
Can I participate in the study if I am not sure I can commit to do the study for 8 consecutive weeks?
Please consider all commitments that you may have prior to participation (travel, work and family obligations, etc). We need you to commit fully to the study for 8 consecutive weeks, so please plan accordingly. If you inform our study staff ahead of time, we will be happy to schedule your participation around these commitments.
Who can I call for answers to other questions I have about the study?
Please do not hesitate to call our study telephone number at 1-800-738-7555 or email
email@example.com if you have any other questions about the study. We are recruiting a total of 130 participants, so we would appreciate it if you are able to help inform others (your husband/wife, friends, colleagues, etc) about the study. Thank you.
I am interested in participating in this study. What should I do?
Thank you for your interest in our study. Please click on the link below to review our Online Prescreening Questionnaire Consent Form. Following your online consent, you will be directed to our Online Prescreening Questionnaire. The questionnaire will take about 30 min to complete. Your responses will help us determine if you might be eligible to participate in the study. If you prefer to complete the questionnaire over the phone with one of our staff members please call 1-800-738-7555 and request study #2720.