The CARB Study

Carbohydrates and Related Biomarkers Study

A feeding study to examine the effect of high and low glycemic carbs and weight on cancer biomarkers

Marian Neuhouser, PhD, RD and Johanna Lampe, PhD, RD, Principal Investigators

John Brunzell, MD, University of Washington, Co-Investigator
Gloria Coronado, PhD, Fred Hutchinson Cancer Research Center, Co-Investigator
Michael Pollak, MD, McGill University, Co-Investigator

If you have questions, please call or email:
Yvonne Schwarz, RD
Study Coordinator
Phone: (206) 667-7804
E-mail: yschwarz@fhcrc.org

Get the complete Carb Study Booklet and Postprandial Test info booklet.

Scientific Basis of the CARB Study

Doctors cannot always explain why one person gets cancer and another does not. Scientists at Fred Hutchinson Cancer Research Center have studied general patterns of cancer to learn about "risk factors" — things in our lives that may increase our chances (or risk) of developing cancer. Risk factors may include a person's weight, the amount of exercise they usually get or the type of foods they eat.

To better understand how foods relate to cancer risk, scientists at the Hutchinson Center want to study the biological markers (biomarkers) of foods that people eat. These biomarkers found in blood an urine, can be levels of nutrients from foods, such as glucose (sugar). They can also include products our bodies make when we eat such as insulin.

The CARB Study is a feeding study. It tests how carbohydrates and other foods you eat affect biomarkers in your blood and urine. We also want to see if people's weight affects their biomarkers

What are carbs?

Carbohydrates (carbs) are foods made of flour, starch or sugar. Carbs include

• pasta, bread, and cake
• grains like rice and barley
• starchy vegetables like potatoes and corn
• foods with natural or added sugar, like fruit and candy

When we eat carbs, our body breaks them down into glucose (sugar). This glucose then goes into the blood. Some carbs, called refined or high glycemic carbs, break down into a high amount of glucose. Other carbs, called complex or low glycemic carbs, break down into a low amount of glucose.

The Feeding Study — a short explanation

We will test 88 men and women between 18 and 45 years old. About half of them will be normal weight and the other half will be overweight. We will test:

• How your body processes high and low glycemic carbs
• If the different types of carbs affect people's biomarkers
• If there is any difference in carb response between people who are normal weight and people who are overweight.

We will give you all your food to eat and drink (except water) for two 28-day feeding periods (a total of 56 days). You will eat dinner at the Hutchinson Center Monday through Friday. Each evening we will give you your breakfast, lunch and snacks for the next day. On Friday evenings we will give you the food for the week-end. There will be at least four weeks between the feeding periods when you will go back to eating your own food. This period could be longer — it will depend on your schedule. Thus you will be part of this study for at least 12 weeks.

We will take samples of your blood after an overnight fast at the beginning and the end of each feeding period. We will ask you to collect all your urine for 24 hours at the end of each feeding period. We will also ask you to complete a number of questionnaires during each diet period. You will be asked to collect a small stool sample, in your own home, before the first feeding period, and once during each feeding period. The stool sample collection is optional. You can decide not to provide a stool sample and still participate in the study. There is also an optional 8-hour Postprandial Test (PPT) on the last day of each feeding period. If interested, see the PPT information booklet.