Vegetables join bladder cancer fight

Dominion Post

THEY ARE GOOD FOR YOU: Vegetable extracts may reduce the incidence of bladder cancer.

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New Zealand researchers have proven generations of mothers are right and United States president George Bush was wrong ... now, eat up your greens!

The first president Bush took broccoli off the White House menu in 1990 with the declaration that he hadn't liked it since his mother made him eat it as child: "And I'm President of the United States and I'm not going to eat any more broccoli".

But the New Zealand researchers have now shown natural chemicals in broccoli sprouts may curb bladder cancer.

Laboratory rats exposed to a chemical that causes bladder cancer are more resistant to the disease if freeze-dried broccoli sprout extract has been added to their food.

Agresearch senior scientist Rex Munday led an international team of researchers which discovered that the broccoli extract can reduce the incidence of bladder cancer -- in an animal "model" - by more than 50 per cent.

The credit may go to nutrients called isothiocyanates, especially one called sulforaphane, which the researchers call "a highly promising cancer chemopreventive agent," according to the study published in the latest edition of Cancer Research.

Sulforaphane is found in cruciferous vegetables, including broccoli and cauliflower, note the researchers, who made their own broccoli sprout extract for the study.

According to the researchers, the findings may explain why people who eat lots of fruits and vegetables - especially cruciferous vegetables - tend to have lower risk of bladder cancer.

Bladder cancer is a major problem, particularly in Western countries, and is diagnosed in more than 300,000 people every year worldwide, and is the fourth commonest cancer in men, and the eighth commonest in women.

Approximately 580 New Zealand men and women are diagnosed with bladder cancer annually, while 170 die from the disease each year.

"It appears that increased consumption of certain vegetables could reduce the incidence of this disease," said Dr Munday.

The broccoli sprout extract did not hurt the rats' bladder cells.

The rats that ate the broccoli sprout extract gained less weight overall but wound up with heavier bladders than rats that didn't get the broccoli sprout extract. Those weight changes were reversed by halting the broccoli sprout extract.

Collaborating with Dr Munday on the project were researchers from Massey University and Crop and Food Research in New Zealand and the Roswell Park Cancer Institute and the Johns Hopkins University in the United States.

In an earlier study supported by the Waikato Medical Research Foundation, the researchers found that rats fed with vegetables of the cabbage family, such as broccoli, cauliflower, Brussels sprouts and watercress, showed an increase in tissue enzymes that protect against chemicals that cause cancer.

"The greatest effect was seen in the bladder, suggesting that such vegetables would protect against bladder cancer," said Dr Munday.

The latest experiment proved the effect.

"This result is consistent with epidemiological studies showing that people who have a high dietary intake of plants of the cabbage family are less likely to develop bladder cancer than those who eat only small amounts of these vegetables," he said.

The researchers are now working on other vegetables and vegetable components to find even more effective materials for the prevention of bladder cancer.

Crop and Food Research nutritional biochemist Dr Carolyn Lister said scientific knowledge about the beneficial effects of vegetables and their components was increasing daily.

"Hopefully these results will encourage people to eat more vegetables that are naturally rich in glucosinolates, particularly those of the cabbage family."

Separately, New Zealand epidemiologists at Massey University have found that peope in sales, particularly women, may have a higher risk of bladder cancer.

Studies have found higher bladder cancer rates among people in various occupations, including hairdressers, textile workers, truck drivers and workers in the rubber, leather and chemical industries. In most cases it is thought that long-term chemical exposures are to blame.

Dr Andrea Mannetje and Dr Neil Pearce of Massey University found that when other factors were considered -- including smoking, a major risk for bladder cancer -- women in sales occupations have an 18 percent higher risk of developing the disease than those in other jobs.

For men, there was no clear overall association between sales jobs and bladder cancer. There was, however, some suggestion that men in car sales had an elevated risk.

- NZPA