Effect of Kale Consumption on Human Xenobiotic Metabolizing Enzymes

The primary objective of this study is to determine how daily consumption of kale changes the activity of human xenobiotic metabolizing enzymes. Secondary objectives are to measure absorption and metabolism of kale phytonutrients, and to determine how kale consumption affects gene expression related to metabolism and lipid measures associated with cardiovascular health.

Study Overview

• Status: Completed
• Conditions: Healthy Volunteers
• Intervention / Treatment: Other: Base Diet; Other: Kale Treatment

Detailed Description

Consumption of Brassica vegetables (which include broccoli, cabbage, and kale) is inversely associated with the incidence of several cancers, including cancers 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 is their rich content of glucosinolates. Glucosinolates are sulfur-containing compounds that are converted to bioactive metabolites by a plant enzyme called myrosinase, which is released when the vesicles containing myrosinase are ruptured by chewing or cutting. These bioactive compounds are considered to be the active agent for cancer prevention. Their ability to reduce risk of cancer may derive in part from their ability to modulate foreign-substance metabolizing enzymes, which include enzymes called Phase I cytochrome P450s and Phase II enzymes.

The primary aim of this study is to investigate how daily consumption of kale influences foreign-substance metabolizing enzymes, which in turn may reduce cancer risk. Secondary aims of this study include measuring metabolism of kale nutrients, effect of kale consumption on fecal microbiota, and how kale consumption influences risk factors for cardiovascular disease.

• Study Type: Interventional
• Enrollment (Actual): 27
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Beltsville, Maryland, United States, 20705
      • USDA-ARS Beltsville Human Nutrition Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 5 years cancer free
• Not a tobacco product user
• Blood glucose less than 126 mg/dL
• Able to voluntarily agree to participate and sign an informed consent document

Exclusion Criteria:

• Brassica vegetable allergy or intolerance
• use of oral contraceptives
• Women who have given birth in the previous 12 months
• 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)
• 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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Base diet; Subjects will consume a base diet prepared using traditional American foods with a macronutrient composition representative of a typical American diet.	Other: Base Diet; Base Diet
Other: Kale Treatment; Subjects will consume 500 g of kale per 2000 kcal of food, split between breakfast and dinner, as a supplement to the base diet.	Other: Kale Treatment; Base Diet plus Kale

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CYP1A2 activity will be analyzed	Plasma will be analyzed for caffeine metabolite ratios	Day 7
CYP1A2 activity will be analyzed	Plasma will be analyzed for caffeine metabolite ratios	Day 14
CYP1A2 activity will be analyzed	Plasma will be analyzed for caffeine metabolite ratios	Day 42
CYP1A2 activity will be analyzed	Plasma will be analyzed for caffeine metabolite ratios.	Day 49

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The ability of fecal microbiota to metabolize glucosinolates will be determined	Fecal samples will be presented with glucosinolates to determine the change in the ability of fecal microbes to metabolize the glucosinolates.	Days 14 and 49.
Metabolites of Kale	Metabolites of Kale will be measured in plasma and urine.	On days 35 and 36
Fecal microbiota will be analyzed for microbial DNA	Fecal microbial communities will be determined using DNA extracted from fecal samples.	Days 0, 14, 35, and 49
UGT1A1 activity will be analyzed	Serum will be analyzed for bilirubin concentration to assess UGT1A1 activity	On days 7, 14, 42, and 49
Glutathione S-transferase alpha concentration	Glutathione S-transferase alpha concentration will be measured in serum	On days 7, 14, 42, and 49
Total cholesterol	Total cholesterol will be measured in serum	On days 0, 7, 14, 35, 42, and 49
LDL cholesterol	LDL cholesterol will be measured in serum	On days 0, 7, 14, 35, 42, and 49
HDL cholesterol	HDL cholesterol will be measured in serum	On days 0, 7, 14, 35, 42, and 49
Triacylglycerides	Triacylglycerides will be measured in serum	On days 0, 7, 14, 35, 42, and 49
Apolipoprotein A1	Apolipoprotein A1 will be measured in serum	On days 0, 7, 14, 35, 42, and 49
Apolipoprotein A2	Apolipoprotein A2 will be measured in serum	On days 0, 7, 14, 35, 42, and 49
Apolipoprotein B	Apolipoprotein B will be measured in serum	On days 0, 7, 14, 35, 42, and 49
Changes in gene expression	messenger RNA concentrations in whole blood will be measured	On days 0, 14, 35, and 49

Collaborators and Investigators

• Sponsor: USDA Beltsville Human Nutrition Research Center

Study record dates

Study Major Dates

• Study Start (Actual): April 18, 2018
• Primary Completion (Actual): August 1, 2018
• Study Completion (Actual): August 1, 2018

Study Registration Dates

• First Submitted: February 22, 2018
• First Submitted That Met QC Criteria: February 22, 2018
• First Posted (Actual): February 28, 2018

Study Record Updates

• Last Update Posted (Actual): September 12, 2018
• Last Update Submitted That Met QC Criteria: September 11, 2018
• Last Verified: September 1, 2018

More Information

Terms related to this study

• Other Study ID Numbers: HS60 - Kale Study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No