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.
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
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
27
Base Diet
Base Diet plus Kale
USDA-ARS Beltsville Human Nutrition Research Center
Beltsville, Maryland, United States
CYP1A2 activity will be analyzed
Plasma will be analyzed for caffeine metabolite ratios
Time frame: Day 7
CYP1A2 activity will be analyzed
Plasma will be analyzed for caffeine metabolite ratios
Time frame: Day 14
CYP1A2 activity will be analyzed
Plasma will be analyzed for caffeine metabolite ratios
Time frame: Day 42
CYP1A2 activity will be analyzed
Plasma will be analyzed for caffeine metabolite ratios.
Time frame: Day 49
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.
Time frame: Days 14 and 49.
Metabolites of Kale
Metabolites of Kale will be measured in plasma and urine.
Time frame: 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.
Time frame: Days 0, 14, 35, and 49
UGT1A1 activity will be analyzed
Serum will be analyzed for bilirubin concentration to assess UGT1A1 activity
Time frame: On days 7, 14, 42, and 49
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Glutathione S-transferase alpha concentration
Glutathione S-transferase alpha concentration will be measured in serum
Time frame: On days 7, 14, 42, and 49
Total cholesterol
Total cholesterol will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
LDL cholesterol
LDL cholesterol will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
HDL cholesterol
HDL cholesterol will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
Triacylglycerides
Triacylglycerides will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
Apolipoprotein A1
Apolipoprotein A1 will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
Apolipoprotein A2
Apolipoprotein A2 will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
Apolipoprotein B
Apolipoprotein B will be measured in serum
Time frame: On days 0, 7, 14, 35, 42, and 49
Changes in gene expression
messenger RNA concentrations in whole blood will be measured
Time frame: On days 0, 14, 35, and 49