Bioavailability of Phytonutrients From Novel Preparations of Broccoli

Bioavailability of Phytonutrients From Novel Preparations of Broccoli

The primary objective of this study is to determine the effects of different methods of broccoli preparation on levels of urinary glucosinolate metabolites. The secondary objective is to determine the effects of different methods of broccoli preparation on levels of plasma carotenoids.

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 including glucosinolates and carotenoids. Glucosinolates are sulfur-containing compounds that are converted to bioactive metabolites by an enzyme called myrosinase, which is released when the vesicles containing myrosinase are ruptured by chewing or cutting. These bioactive compounds are considered to be active agents 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. Carotenoids may also have a role in cancer prevention and other health benefits including reducing age-related macular degeneration, and therefore merit research to reveal factors that affect their presence in the body.

The primary aim of this study is to investigate how various preparations of broccoli impact levels of these healthful nutrients in humans.

Inclusion Criteria:

• Between 21 and 75 years old at beginning of study

Exclusion Criteria:

• Pregnant, lactating, or intending to become pregnant during the study period
• Women who have given birth during the previous 12 months
• Presence of kidney disease, liver disease, gout, certain cancers, gastrointestinal disease, hyperthyroidism, untreated or unstable hypothyroidism, pancreatic disease, other metabolic diseases, or malabsorption syndromes requiring special diets
• History of certain cancers within last 3 years
• Known allergy or intolerance to Brassica vegetables
• History of eating disorders or other dietary patterns which are not consistent with the dietary intervention (e.g., vegetarians, very low-fat diets, high-protein diets)
• Colonoscopy during three weeks prior to start of study
• Unwillingness to abstain from probiotics or vitamin, mineral, herbal and glucosinolate/isothiocyanate supplements for two weeks prior to the study and during the study
• Use of tobacco products within 6 months preceding study
• Crohn's disease or diverticulitis
• Suspected or known strictures, fistulas or physiological/mechanical GI obstruction
• 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
• Fasting glucose greater than or equal to 126 mg/dL
• 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 treatment 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