Two studies link broccoli sprouts and cruciferous vegetables to powerful anti-cancer benifits.  The studies were presented at the American Association for Cancer Research’s Sixth Annual International Conference.

Both studies focused on the impact on the risk of bladder cancer, and isothiocyanates (ITCs), a well-known class of cancer prevention agents. Cruciferous vegetables and broccoli sprouts contain relatively high amounts of ITCs.

Broccoli Sprouts

“The bladder is like a storage bag, and cancers in the bladder occurs almost entirely along the inner surface, the epithelium, that faces the urine, presumably because this tissue is assaulted all the time by noxious materials in the urine,” said senior author Yuesheng Zhang, M.D., Ph.D, professor of oncology at Roswell Park Cancer Institute. “The ITCs in broccoli sprout extracts after oral ingestion are selectively delivered to the bladder epithelium through urine excretion.”

Using a rat model of bladder cancer, Zhang and his colleagues found that freeze-dried aqueous extract of broccoli sprouts significantly inhibited bladder cancer development. Researchers also found that the higher the dose of the extract, the greater the protection. Importantly, the extract itself caused no observable changes in the bladder, yet it inhibited the incidence, multiplicity, size and progression of bladder cancer.

According to Zhang, the protective effect of the extracts was associated with a significant increase in the bladder of several enzymes that are known to protect against oxidants and carcinogens.

Within 12 hours after a dose, more than 70 percent of the ITCs present in the extracts were excreted into the urine, indicating high absorption by the body and rapid urinary excretion.

Researchers also found that ITCs “targeted” the high risk bladder epithelium. Concentrations of ITCs were higher in the urine than in the blood or liver indicating that the ITCs in the extracts are efficiently and selectively delivered to the bladder epithelium, where cancer usually occurs.

Cruciferous Vegetables

While researchers have long known that cruciferous vegetables are high in ITCs, how much one needed to eat to reap the protective benefits is not known.

Researchers from Roswell Park Cancer Institute report that just three or more servings a month of raw cruciferous vegetables like broccoli, cabbage and cauliflower, may reduce bladder cancer risk by approximately 40 percent, overall. Serve up the Chinese Chicken Salad please.

Roswell Park researchers reviewed lifestyle factors and dietary habits of 275 individuals with primary bladder cancer and 825 individuals without cancer. They found a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetable consumption.

Previous research had surveyed intake of any cruciferous vegetables, raw or cooked, and results were inconsistent. “Cooking can reduce 60 to 90 percent of ITCs,” says Li Tang, M.D., Ph.D. of Roswell Park Cancer Institute and lead researcher on this study. “Heating destroys the enzyme that converts the precursor glucosinolates into ITCs, and also destroys ITCs already formed, which is why you need to eat raw cruciferous vegetables to receive the food’s maximum benefit.”

A key factor in the research was that it’s a survey of raw cruciferous vegetables.

“Cooking can reduce 60 to 90 percent of ITCs,” says Li Tang, M.D., Ph.D. of Roswell Park Cancer Institute and lead researcher on this study. “Heating destroys the enzyme that converts the precursor glucosinolates into ITCs, and also destroys ITCs already formed, which is why you need to eat raw cruciferous vegetables to receive the food’s maximum benefit.”

Source
American Association for Cancer Research