AACR Prevention: Raw Cruciferous Vegetables Cut Bladder Cancer Risk


PHILADELPHIA, Dec. 6 -- Uncooked broccoli or other cruciferous vegetables significantly reduce the risk of bladder cancer, epidemiologists said here today.
Action Points --->
Explain that the study found that nonsmokers who ate three or more servings per month of raw broccoli, cauliflower, or cabbage had a reduced risk of developing bladder cancer.
Point out that this was a case-control study, not a randomized, prospective trial, so that a direct cause-and-effect relationship cannot be proven.
This study was published as an abstract at a conference. These data and conclusions should be considered to be preliminary as they have not yet been reviewed and published in a peer-reviewed publication.
The greatest benefit was for nonsmokers who consumed three helpings per month or more, they said.
So it appeared from a hospital-based, case-control study of 275 patients with bladder cancer and 825 age- and sex-matched people without cancer, Susan McCann, Ph.D., of Roswell Park Cancer Institute in Buffalo, N.Y., and colleagues reported at the American Association for Cancer Research's prevention conference.
"We observed a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetables," said Dr. McCann.
The adjusted odds ratio for developing bladder cancer for the most frequent consumers of raw cruciferous vegetables versus the least frequent was 0.64 (95% CI: 0.42 to 0.97), Dr. McCann said. The protective effect of raw cruciferous vegetables was greatest in nonsmokers claiming three or more servings per month (adjusted odds ratio: 0.27, 95% CI: 0.13 to 0.56).
From 1982 through 1998, the participants completed questionnaires on demographics, lifestyle factors such as alcohol and tobacco use, occupation, medical history, reproductive status (women only), and the frequency with which they consumed different kinds of foods in the past.
"This particular questionnaire asked about both raw and cooked vegetables [separately]," said Dr. McCann. Most food consumption surveys don't distinguish between cooked and uncooked foods, she noted.
Li Tang, M.D., Ph.D., of Roswell Park, a co-investigator, said cooking reduces availability of isothiocyanates, the compounds in cruciferous vegetables thought to be responsible for the protective effect.
The participants estimated their consumption of specific raw and cooked cruciferous vegetables, including broccoli, cauliflower, and cabbage, as well as total fruits, total vegetables, and total cruciferous vegetables (cooked and uncooked combined).
The study found no association with bladder cancer occurrence for any food category other than raw cruciferous vegetables.
The dose-response trend toward decreased bladder cancer incidence with increasing frequency of eating raw cruciferous vegetables was clearly significant (P=0.003), Dr. McCann said.
Bladder cancer patients reported eating raw cruciferous vegetables 4.5 times per month on average prior to their diagnosis, she said, whereas the frequency for controls was 5.9 per month.
Dr. McCann noted that, while nonsmokers appeared to get the most benefit from raw cruciferous vegetables, "we also saw a protective effect for heavy smokers."
Smokers with lifetime exposure of more than 33 pack-years showed a 40% reduction in bladder cancer risk with high consumption of raw cruciferous vegetables, Dr. McCann said.
Among all current smokers, she added, the risk reduction with high raw cruciferous vegetable intake was 50%.
Dr. McCann said that participants' actual consumption of particular foods may differ from what they reported because they were recalling what they ate years earlier.
"You can't really estimate exact nutrient intake," Dr. McCann said. "But you can rank people, so you can get an idea of who is high or low in a certain food group or a certain nutrient intake. That will allow you to estimate associations with disease."
She said the group's epidemiological results were in line with experimental data showing extracts from cruciferous vegetables to block cancer development in cell lines and animal models.
The study was funded by the National Cancer Institute.
No conflicts of interest were reported.
Primary source: American Association of Cancer Research: PreventionSource reference:Tang L, "Consumption of raw, but not cooked, cruciferous vegetables and reduction of bladder cancer risk" AACR Prevention Meeting 2007.

Vitamin D cuts cancer risk in study of U.S. women

By Will DunhamFri Jun 8, 2:16 PM ET
Large doses of vitamin D may reduce the risk of cancer, according to a four-year U.S. study published on Friday involving nearly 1,200 women over the age of 55 in rural Nebraska.
Women who took calcium and a dose of vitamin D almost three times the U.S. government's recommended daily intake for middle-aged adults saw a 60 percent lower incidence of all cancers than women not taking the vitamin, the study found.
The study, conducted by researchers at the Creighton University School of Medicine in Omaha, Nebraska, was published in the American Journal of Clinical Nutrition.
Joan Lappe, a Creighton professor of medicine who led the study, said vitamin D may be an effective way to guard against cancer but many people worldwide do not get enough of it.
"I'm really very excited because I think the vitamin D deficiency issue is a major health concern that we need to address, and perhaps this will bring it to the forefront," Lappe said in a telephone interview.
Lappe said additional research is needed to figure out whether the protective effect seen in the older white women also applied to men, younger women and other ethnic groups.
The American Cancer Society reacted cautiously, calling it a small study. Only 50 of the 1,179 women developed cancer, making broad conclusions difficult, said Dr. Michael Thun, who heads epidemiological research for the society.
Thun said another weakness was that the researchers initially did not set out to examine the effect of vitamin D on cancer, but on bone health in post-menopausal women.
"The results are provocative" but not sufficient for the society to recommend people take vitamin D supplements to ward off cancer, Thun said in a telephone interview.
A number of studies have found protective properties from higher intake of vitamin D for cancers and other ailments. For example, other researchers in December found people with higher levels of vitamin D had a lower risk of multiple sclerosis.
SUNLIGHT EXPOSURE
The body makes the vitamin after being exposed to sunlight. Not many foods are naturally rich in it. It is found in fatty fish such as salmon and milk commonly is fortified with it.
Vitamin D promotes absorption of calcium necessary for healthy teeth and bones. It is also important to nerve cells, including the brain, and seems to act as a regulator of the immune system.
The women in the study were from a nine-county area of rural eastern Nebraska and had no known cancers for at least a decade before it began in 2000.
They were broken into three groups, either getting 1,400 to 1,500 mg of a calcium supplement daily, getting that calcium plus 1,100 IU (international units) of vitamin D3, or getting placebos.
After four years, 20 women in the placebo group got cancer, 17 in the calcium-only group got cancer and 13 in the vitamin D3 and calcium group got cancer.
Figuring some women may have entered the study with undiagnosed cancer, the researchers excluded the results in the first year and assessed only the final three. The findings became even more powerful, with the women getting calcium and vitamin D3 experiencing a 77 percent lower cancer risk.
The researchers found no statistically significant difference in cancer risk for the groups getting calcium alone or placebos.
(Additional reporting by Natasha Elkington)

Early menopause related to bladder cancer risk

NEW YORK (Reuters Health) - Women who are relatively young when they go through menopause seem to be at increased risk of developing bladder cancer, researchers from the University of Minnesota School of Public Health in Minneapolis report.
Bladder cancer is quite common in the U.S., representing about 6 percent of all new cancer cases among men and 2 percent among women, Anna E. Prizment and colleagues point out in the International Journal of Cancer. It's well known that smoking and chemical carcinogens increase the risk, and that it goes up with age.
The researchers looked for factors associated with bladder cancer in a study of 37,459 women between the ages of 55 and 69 years from Iowa. The women were initially free from cancer in 1986, and they were followed through 2003.