Brassica Intake and Isothiocyanate Absorption

USDA Beltsville Human Nutrition Research Center18 enrolled

Overview

Healthy individuals (n=18) will participate in 2 controlled-feeding study periods that are 3 weeks each in length: 1) Control diet 2) Brassica diet. The control diet will consist of typical American foods and will be free of Brassica vegetables and free of glucosinolates and isothiocyanates. The Brassica diet will contain the control diet plus glucosinolate/isothiocyanate treatment foods. There will be a break of 3 weeks in between study periods. Blood, urine, and fecal samples will be collected at the end of each study period. Eligible participants will be selected based on genotype for glutathione S-transferase (GST), which has been shown to influence the potential protective role of dietary Brassicas. Half the participants (n=9) will be GSTM1-positive individuals and half (n=9) will have the GSTM1-null genotype.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Masking

SINGLE

Enrollment

Conditions

Healthy Volunteers

Interventions

Eligibility

Sex: ALLMin age: 21 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Between 21 - 70 years of age * Not currently taking glucosinolate/ITC containing supplements * Voluntarily agree to participate and sign an informed consent document * Free of cancer (never diagnosed or cancer-free for at least 5 y) Exclusion Criteria: * Pregnant, lactating, or intend to become pregnant during the study period * Known allergy or intolerance to Brassica vegetables * History of bariatric surgery or nutrient malabsorption disease (such as celiac disease) or other metabolic disorders requiring special diet recommendations * Use of tobacco products * Use of certain medications (prescription or over-the-counter) that may interfere with the study objectives * Type 2 diabetes requiring the use of diabetes pills, insulin, or non-insulin shots * Use of blood-thinning medications such as Coumadin (warfarin), Dicumarol, or Miradon (anisindione) * Unable or unwilling to give informed consent or communicate with study staff * Self-report of alcohol or substance abuse within the past 12 months and/or current acute treatment or rehabilitation program for these problems (long-term participation in Alcoholics Anonymous is not an exclusion) * Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol

Outcomes

Primary Outcomes

Total isothiocyanates (ITC)

At the end of each study period, total ITC equivalents will be measured in blood and urine over a 24-hour period.

Time frame: 24-hr

Secondary Outcomes

Fecal microbiota

Fecal microbiota will be measured at the end of each 3-week study period.

Time frame: End of 3-week study period

Gastrointestinal health

At the end of each 3-week study period, urine will be collected for 8 hours as part of the lactulose-mannitol test, which is a measure of gastrointestinal health.

Time frame: 8-hr