USDA - Diet-Genetic Interactions - Examine Absorption of Isothiocyanates & Carotenoids Derived from Freeze-Dried Broccoli

National Cancer Institute, Frederick MD

Investigators

Abstract

The purpose of this research is to investigate the absorption of isothiocyanates and carotenoids derived from freeze-dried broccoli. A secondary objective is to evaluate the palatability of freeze-dried broccoli as a snack product. Demonstration of palatability of freeze-dried broccoli as well as ability to provide bioavailable phytonutrients will provide incentive for the food industry to consider increasing development and production of freeze-dried broccoli snacks. Availability of such snacks in the marketplace could potentially reduce consumption of snacks with ?empty calories? as they are replaced with more healthful snacks, thereby reducing risk of cancer and other chronic diseases. This Inter-Agency Agreement will capitalize on joint expertise of the NCI DCP NSRG and the USDA Beltsville Human Nutrition Research Center to conduct a human feeding study to better evaluate absorption of phytonutrients from freeze-dried broccoli stems and florets. The study will be conducted as a randomized, controlled clinical trial with two treatment arms that are 3 weeks in length. During both treatment arms, volunteers will consume a self-selected, free-living Brassica-free diet that is also low in carotenoids. For one treatment arm volunteers will consume 30 g of freeze-dried broccoli daily (the equivalent of 300 g of raw broccoli, or 2 servings) for 3 weeks. The control food will be white popcorn and will be consumed in place of the broccoli during the control arm. At the beginning and end of each treatment period, volunteers will provide a 24-hour urine collection and a fasting blood sample. The urine will be evaluated for isothiocyanates and flavonoids, and carotenoid levels will be measured in blood samples. Volunteers will also participate in a food acceptability evaluation at the beginning and end of each treatment period. Bio-specimens will also be collected for ancillary measures, which may include oral microbiome, metabolomics and gene expression after consumption of freeze-dried broccoli stems and florets and compared to control, with a focus on cancer pathways.