Healthy Volunteers
Conditions
Brief summary
The objectives of the study are 1) to determine the influence of daily consumption of well-cooked broccoli on plasma and urinary glucosinolate metabolites, and 2) to determine inflammatory marker changes consistent with decreased cancer risk.
Detailed description
Consumption of Brassica vegetables is inversely associated with incidence of several cancers, including cancer of the lung, stomach, liver, colon, rectum, breast, endometrium, and ovaries. Brassica vegetables are a good source of many nutrients, but the unique characteristic of Brassicas (Broccoli in particular) is their rich content of glucosinolates. Glucosinolates are sulfur-containing compounds that are converted to isothiocyanates (ITC) by an enzyme in the plant called myrosinase, which is released when the vesicles containing myrosinase are ruptured by chewing or cutting. The isothiocyanates are considered to be the active agent for cancer prevention. Some of the mechanisms by which isothiocyanates likely inhibit cancer include modulation of cytochrome P450 enzymes, induction of phase II enzymes, and apoptosis. The aim of this study is to investigate how daily consumption of broccoli with myrosinase inactivated by cooking influences glucosinolate metabolism and absorption, and consequent regulation of inflammatory markers.
Interventions
OTHERControl Diet
Participants will receive a controlled diet with 0 g/d of broccoli. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet.
OTHERBase Diet with Broccoli
Participants will receive a controlled diet with 100 g of broccoli at both breakfast and dinner daily. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet.
Sponsors
USDA Beltsville Human Nutrition Research Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
21 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* Non tobacco user * Cancer Free * Not currently taking glucosinolate/isothiocyanate containing supplements
Exclusion criteria
* 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 (anisinidione) * History of bariatric surgery or nutrient malabsorption disease * Pregnant, lactating, or intending to become pregnant during the study period * Crohn's disease or diverticulitis * Suspected or known strictures, fistulas or physiological/mechanical GI obstruction * 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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The change in glucosinolate metabolites will be measured in blood plasma and urine | At end of diet period 1 (week 3) and at the end of diet period 2 (week 12) | To track the change of endogenous broccoli isothiocyanates in this crossover study, glucosinolate metabolites will be measured in both blood plasma and urine |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Body composition will be determined by dual energy x-ray absorptiometry (DEXA) | Day 0, just prior to beginning the controlled diet | Determine fat, lean, and bone mineral mass, and visceral fat deposition in our subjects |
| The ability of fecal microbiota to metabolize glucosinolates will be determined | once per week during diet periods 1 and 2 (weeks 1, 2, 3, 10, 11, and 12) | Fecal samples will be presented with glucoraphanin to determine the ability of fecal microbes to metabolize it |
| Fecal microbiota will be analyzed for microbial DNA | once at the beginning and end of diet periods 1 and 2 (weeks 1, 3, 10, and 12) | Fecal microbial communities will be determined using DNA extracted from fecal samples |
| Markers of gut health will be analyzed in blood | once in the third week of diet periods 1 and 2 (weeks 3 and 12) | Zonulin in blood serum will be measured by ELISA |
| Markers of inflammation will be measured in blood | at end of diet period 1 (week 3) and at end of diet period 2 (week 12) | Cytokines and acute phase proteins will be measured in blood |
Countries
United States
Outcome results
None listed