It turns out Mom was right – you should eat your broccoli. But what Mom may not have known is why broccoli is so healthy, and how its lesser known, younger offshoot may be a powerful anti-cancer agent.

Researchers at the Linus Pauling Institute at Oregon State University have found that sulforaphane – a compound found in cruciferous vegetables such as broccoli, bok choy and brussels sprouts – has strong anti-cancer properties.

Even more promising results have been found in broccoli sprouts. The tiny, thread-like broccoli sprouts sold at stores next to alfalfa sprouts have more than 50 times the amount of sulforaphane than found in mature broccoli.

Emily Ho, a researcher with the Linus Pauling Institute and an assistant professor in the Department of Nutrition and Exercise Sciences at OSU, will describe these dietary inhibitors for cancer prevention at the conference on “Diet and Optimum Health,” organized by the Linus Pauling Institute. The conference will be held May 16-19 at the Hilton Hotel in Portland. Ho will speak at 10:30 a.m. Friday, May 18.

Ho’s main area of research is on the dietary prevention of prostate cancer. The Asian diet could be a key in this prevention. White males born in the United States have dramatically higher rates of prostate cancer than Asian men. But when Asian men live in the U.S. for five years or more, their rates of prostate cancer rise significantly, Ho says.

Past studies in Ho’s lab have focused on dietary elements in cancer prevention such as green tea and soy.

In her new study, which was published in the Journal of the Society of Experimental Biology and Medicine, Ho and her colleagues at Linus Pauling Institute looked at cruciferous vegetables. While many cruciferous vegetables have sulforaphane, broccoli and broccoli sprouts have the highest amount and thus could be a major player in the prevention of prostate and colon cancer.

Ho said drugs classified as histone deacetylase (HDAC) inhibitors are being looked at as potentially preventing cancer. She said their research shows that these same effects of inhibiting HDAC might be obtained by consumption of cruciferous vegetables.

“I would say if you’re at all worried about cancer or at high risk of cancer, especially of prostate or colon cancer, then increasing your dietary intake of broccoli and other vegetables could be a good idea,” Ho said.

“It certainly can’t hurt. And drugs can have negative side effects and be difficult to administer.”

While Ho said the research is not at the point where she can make a specific recommendation on how much broccoli or bok choy to eat, she personally tries to have two servings of cruciferous vegetables a day.

In human subjects, just eating some broccoli sprouts on top of a bagel with cream cheese resulted in HDAC inhibition.

“The compound in broccoli may be one of the strongest anti-cancer fighters we have,” Ho said.

Oregon State University (2007, May 18). Eat Your Broccoli: Study Finds Strong Anti-Cancer Properties In Cruciferous Veggies. ScienceDaily. Retrieved July 25, 2010, from http://www.sciencedaily.com­ /releases/2007/05/070517100315.htm

A compound derived from broccoli could help prevent or treat breast cancer by targeting cancer stem cells — the small number of cells that fuel a tumor’s growth — according to a new study from researchers at the University of Michigan Comprehensive Cancer Center.

The study tested sulforaphane, a component of broccoli and broccoli sprouts, in both mice and cell cultures. Researchers found sulforaphane targeted and killed the cancer stem cells and prevented new tumors from growing.

“Sulforaphane has been studied previously for its effects on cancer, but this study shows that its benefit is in inhibiting the breast cancer stem cells. This new insight suggests the potential of sulforaphane or broccoli extract to prevent or treat cancer by targeting the critical cancer stem cells,” says study author Duxin Sun, Ph.D., associate professor of pharmaceutical sciences at the U-M College of Pharmacy and a researcher with the U-M Comprehensive Cancer Center.

Results of the study appear in the May 1 issue of Clinical Cancer Research.

Current chemotherapies do not work against cancer stem cells, which is why cancer recurs and spreads. Researchers believe that eliminating the cancer stem cells is key to controlling cancer.

In the current study, researchers took mice with breast cancer and injected varying concentrations of sulforaphane from the broccoli extract. Researchers then used several established methods to assess the number of cancer stem cells in the tumors. These measures showed a marked decrease in the cancer stem cell population after treatment with sulforaphane, with little effect on the normal cells. Further, cancer cells from mice treated with sulforaphane were unable to generate new tumors. The researchers then tested sulforaphane on human breast cancer cell cultures in the lab, finding similar decreases in the cancer stem cells.

“This research suggests a potential new treatment that could be combined with other compounds to target breast cancer stem cells. Developing treatments that effectively target the cancer stem cell population is essential for improving outcomes,” says study author Max S. Wicha, M.D., Distinguished Professor of Oncology and director of the U-M Comprehensive Cancer Center.

The concentrations of sulforaphane used in the study were higher than what can be achieved by eating broccoli or broccoli sprouts. Prior research suggests the concentrations needed to impact cancer can be absorbed by the body from the broccoli extract, but side effects are not known. While the extract is available in capsule form as a supplement, concentrations are unregulated and will vary.

This work has not been tested in patients, and patients are not encouraged to add sulforaphane supplements to their diet at this time.

Researchers are currently developing a method to extract and preserve sulforaphane and will be developing a clinical trial to test sulforaphane as a prevention and treatment for breast cancer. No clinical trial is currently available.

Journal Reference:

1. Y. Li, T. Zhang, H. Korkaya, S. Liu, H. F. Lee, B. Newman, Y. Yu, S. G. Clouthier, S. J. Schwartz, M. S. Wicha, D. Sun. Sulforaphane, a Dietary Component of Broccoli/Broccoli Sprouts, Inhibits Breast Cancer Stem Cells. Clinical Cancer Research, 2010; 16 (9): 2580 DOI: 10.1158/1078-0432.CCR-09-2937

Light has been cast on the interaction between broccoli consumption and reduced prostate cancer risk. Researchers writing in BioMed Central’s open access journal Molecular Cancer have found that sulforaphane, a chemical found in broccoli, interacts with cells lacking a gene called PTEN to reduce the chances of prostate cancer developing.

Richard Mithen, from the Institute of Food Research, an institute of BBSRC, worked with a team of researchers on Norwich Research Park, UK, to carry out a series of experiments in human prostate tissue and mouse models of prostate cancer to investigate the interactions between expression of the PTEN gene and the anti-cancer activity of sulforaphane. He said, “PTEN is a tumour suppressor gene, the deletion or inactivation of which can initiate prostate carcinogenesis, and enhance the probability of cancer progression. We’ve shown here that sulforaphane has different effects depending on whether the PTEN gene is present.”

The research team found that in cells which express PTEN, dietary intervention with SF has no effect on the development of cancer. In cells that don’t express the gene, however, sulforaphane causes them to become less competitive, providing an explanation of how consuming broccoli can reduce the risk of prostate cancer incidence and progression.

According to Mithen, “This also suggests potential therapeutic applications of sulforaphane and related compounds.”

Journal Reference:

1. Maria H. Traka, Caroline A. Spinks, Joanne F. Doleman, Antonietta Melchini, Richard Y. Ball, Robert D. Mills and Richard F. Mithen. The dietary isothiocyanate sulforaphane modulates gene expression and alternative gene splicing in a PTEN null preclinical murine model of prostate cancer. Molecular Cancer, 2010; (in press) [link]