URBANA - A new University of Illinois study shows that tomatoes and broccoli--two vegetables known for their cancer-fighting qualities--are better at shrinking prostate tumors when both are part of the daily diet than when they're eaten alone.
"When tomatoes and broccoli are eaten together, we see an additive effect. We think it's because different bioactive compounds in each food work on different anti-cancer pathways," said University of Illinois food science and human nutrition professor John Erdman.
In a study published in the January 15 issue of Cancer Research, Erdman and doctoral candidate Kirstie Canene-Adams fed a diet containing 10 percent tomato powder and 10 percent broccoli powder to laboratory rats that had been implanted with prostate cancer cells. The powders were made from whole foods so the effects of eating the entire vegetable could be compared with consuming individual parts of them as a nutritional supplement.
Other rats in the study received either tomato or broccoli powder alone; or a supplemental dose of lycopene, the red pigment in tomatoes thought to be the effective cancer-preventive agent in tomatoes; or finasteride, a drug prescribed for men with enlarged prostates. Another group of rats was castrated.
After 22 weeks, the tumors were weighed. The tomato/broccoli combo outperformed all other diets in shrinking prostate tumors. Biopsies of tumors were evaluated at The Ohio State University, confirming that tumor cells in the tomato/broccoli-fed rats were not proliferating as rapidly. The only treatment that approached the tomato/broccoli diet's level of effectiveness was castration, said Erdman.
"As nutritionists, it was very exciting to compare this drastic surgery to diet and see that tumor reduction was similar. Older men with slow-growing prostate cancer who have chosen watchful waiting over chemotherapy and radiation should seriously consider altering their diets to include more tomatoes and broccoli," said Canene-Adams.
How much tomato and broccoli should a 55-year-old man concerned about prostate health eat in order to receive these benefits? The scientists did some conversions.
You'd need to eat a cup and a half of broccoli and a half cup of tomato paste to get a similar dose scaled up to human size. I do not see consumption of so much tomato paste as a problem. But the broccoli? Ugh.
"To get these effects, men should consume daily 1.4 cups of raw broccoli and 2.5 cups of fresh tomato, or 1 cup of tomato sauce, or ½ cup of tomato paste. I think it's very doable for a man to eat a cup and a half of broccoli per day or put broccoli on a pizza with ½ cup of tomato paste," said Canene-Adams.
What I want to know: Can cabbage serve in place of broccoli as a prostate cancer risk reducer?
Tomatoes reduce testosterone in rats. Do they have this effect in humans?
Another recent Erdman study shows that rats fed the tomato carotenoids phytofluene, lycopene, or a diet containing 10 percent tomato powder for four days had significantly reduced testosterone levels. "Most prostate cancer is hormone-sensitive, and reducing testosterone levels may be another way that eating tomatoes reduces prostate cancer growth," Erdman said.
I've long suspected that many common foods have pharmacological efffects. If a large study systematically put people on a variety of controlled diets with few foods each diet and then measured many hormones and other blood markers my guess is all sorts of interactions would pop up from the data. Lots of compounds in foods accidentally bind in locations in human bodies and cause changes in how our metabolisms function.
|Share |||Randall Parker, 2007 January 23 11:20 PM Aging Diet Cancer Studies|