Harry Belafonte, Colin Powell, John Kerry, Bob Dole, Arnold Palmer, Norman Schwarzkopf, and Robert Goulet chose surgery. Rudolph Guiliani, Nelson Mandela, and Rupert Murdoch went with radiation. Gregory Hines, Linus Pauling, Frank Zappa, Telly Savalas, and Timothy Leary died of the disease. Anyone who’s past middle age can add the names of friends, fathers, brothers, and others who have or had prostate cancer. That’s what happens when a disease hits one in six men.
Yet, it’s not the worst cancer you can get. The odds of surviving prostate cancer for five years are 98 percent, up from 67 percent in the mid-’70s. That’s a higher survival rate than for any common cancer (except non-melanoma skin). After 10 years, 84 percent of patients are still alive. Nevertheless, prostate cancer is a source of immeasurable suffering and loss. And while researchers have stepped up their efforts to find foods or supplements that might keep tumors from starting or spreading, their findings have yet to yield a slam dunk. Here’s an A-to-Z guide to what they’ve learned so far.
| Alpha-Linoleic Acid And Flaxseed |
The findings are contradictory. In studies of thousands of men, the risk of prostate cancer is 70 percent higher in those who consumed alpha-linolenic acid, or ALA – an omega-3 fat found in meat, vegetable oils, and other foods. So, it seems surprising that flaxseed, one of the richest sources of ALA, lowered PSA levels in a pilot study of 15 men last year. But until more research results are in, it makes sense to avoid too much ALA, especially from concentrated sources like flaxseed oil supplements.
Calcium is everywhere – with dozens of foods now fortified with this mineral. You’d never guess that too much calcium may raise a man’s risk of prostate cancer. Yet, that’s what several researches show. "In earlier studies, we saw roughly four times the risk of advanced prostate cancer only in men who consumed at least 2,000 mg of calcium a day, compared with men who consumed less than 500 mg a day," says Ed Giovannucci of the Harvard School of Public Health. That’s more than the current 1,200 mg a day that experts recommend for men.
How could calcium harm the prostate? Some researchers believe that a high calcium intake lowers levels of vitamin D in the blood. (Taking extra vitamin D doesn’t help.) Less D may make it easier for cells to lose their normal structure and to proliferate, two hallmarks of cancer cells. "That’s far from proven," says Giovannucci. "But there’s no benefit for men to take 1,500 mg or more of calcium a day anyway."
The Health Professionals Follow-up Study has tracked more than 47,000 men since 1986. Those who reported eating fish more than three times a week had a 44 percent lower risk of metastatic prostate cancer over the next 12 years compared with those who reported eating fish less than twice a month. (Fish oil supplements had no impact on risk.) Fish may appear protective because people who eat more seafood often eat less red meat, which is linked to a higher risk of prostate cancer in some studies. "It’s hard to tease that out," says Giovannucci. "Only a few studies suggest that fish may protect against prostate cancer, but it’s still prudent for you to increase fish and to decrease red meat intake," advises Giovannucci.
American men are three times more likely than Japanese men – and 18 times more likely than Chinese men – to die of prostate cancer. Why? One theory is that green tea may protect Asian men. Research, however, has produced conflicting results. In one study, green tea components were effective in killing prostate cancer cells in the laboratory. However, in one clinical study, the PSA levels of prostate cancer patients continued to rise despite an intake of six cups of green tea a day. "We need more clinical trials to find out," concludes Amina Jator, an oncologist at the Mayo Clinic.
Dean Ornish, MD, head of the Preventive Medicine Research Institute at the University of California in San Francisco, studied 90 men who had chosen to "wait and see" rather than have surgery or other treatment for their early-stage prostate cancer. After one year, the men who were placed on a vegan diet (who were getting 10 percent of their calories from fat), had a small but statistically significant drop in PSA levels, while the control group had a rise in PSA. The study hasn’t been replicated. Still, says Mark Moyad of the University of Michigan Urology Center, "Any diet that protects against heart disease is worth eating. The worst-case scenario is that you only reduce the risk of the No. 1 cause of death. We have plenty of men who have beaten prostate cancer only to die of something else. The goal is to live long – not to beat just one disease."
"Studies have found a higher risk in men whose levels of selenium in their blood are low," says W. Robert Lee of Wake Forest University in North Carolina. But the buzz about selenium may be causing other problems. "We’ve got a population of men overdosing on the stuff," says Moyad. Too much selenium is toxic, he points out. "We’ve seen some men showing up with hair loss and dizziness." (To avoid toxicity, don’t exceed 200 mcg a day, the dose used in most studies.)
The good news: The US National Cancer Institute is testing whether selenium (and vitamin E) can prevent prostate cancer in more than 32,000 men. The bad news: Results are not expected until 2013.
The soy story is still unfolding. A recent Asian study does suggest that soy protects the prostate. And prostate cancer rates are low in Asia, but "they’re increasing dramatically," says Mark Messina, a professor at Loma Linda University. Soy has failed to lower PSA levels in three studies in men, and slowed the rise in PSA in a fourth. "So far, it looks like not much happens to the PSA when people eat soy," says Wake Forest’s Lee. But there are some researchers who think that traditional soy foods are worth the gamble. "Soy is heart-healthy and the No. 1 cause of death in men is heart disease," says Lee.
| Tomato Sauce and Lycopene |
It has now been almost 10 years since it was discovered that men who eat tomatoes at least twice a week have a lower risk of prostate cancer. "Researchers recently looked at all the literature and found a 20 percent reduced risk in studies that looked at cooked, not raw, tomatoes," says Harvard’s Giovannucci. Lycopene may explain why cooked tomatoes seem to be more protective than raw. "One serving of tomato sauce has much more lycopene than a fresh tomato or a glass of tomato juice," says Giovannucci. Lycopene – the pigment that gives tomatoes, pink grapefruit, watermelon, and guava their red color – is also an antioxidant that’s concentrated in the prostate gland.
Summing it up, Giovannucci concludes, "We don’t have enough evidence to recommend that men take lycopene, but we do have enough to recommend that they eat tomato products twice a week."
Zinc is concentrated in the prostate, so some people say that it’s bad if you’re not getting enough. But it has been found that at intakes well beyond the US Recommended Daily Allowance (which is only 15 mg), it increases prostate cancer risk. "Zinc is a disaster," says Michigan’s Moyad. "Larger doses increase bad cholesterol, decrease good cholesterol, suppress the immune system, interfere with some bone-building drugs, and potentially raise testosterone levels."
"It’s the No. 1 touted product for the prostate, and there’s no good evidence for taking it!"
• Cut back on red meat and shoot for two or three servings of fish a week.
• Try for at least two servings a week of tomato sauce (preferably on pasta or other dishes that aren’t smothered in cheese).
• Take a multivitamin with roughly a day’s worth of vitamin E (30 IU) and selenium (55 mcg).
• Don’t take more zinc than you’d get in an ordinary multivitamin (15 mg).
• Don’t assume that more calcium is better. Don’t exceed the recommended calcium intakes (1,200 mg a day for men over 50 and 1,000 mg a day for men 50 and under, from food and supplements combined).
• Until researchers know more about alpha-linoleic acid (ALA), avoid flaxseed oil supplements.
