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JULY/AUGUST 2004 VOLUME 31 / NUMBER 6
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Photo: VVG/Science Photo Library.
H ARRY BELAFONTE, Colin Powell, John Kerry, Bob Dole, Arnold Palmer, Norman
Schwarzkopf, and Robert Goulet chose surgery. Rudolph Guiliani, Nelson
Mandela, Richard Riordan, Charlton Heston, 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.
Death rates are down 20 percent since the peak in the early 1990s. But prostate cancer is
still expected to strike 230,100 men and claim 29,900 lives this year.
Here’s the latest on what may—or may not—keep your name off the list.
(Continued on page 3)
Photo: A prostate cancer cell divides.
C O V E R S T O R Y
More Questions than Answers
t’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-1970s. That’s a higher
survival rate than for any common cancer (except non-melanoma skin). After ten
years, 84 percent of patients are still alive.
Nevertheless, prostate cancer is a source of immeasurable suffering and loss. And
& Flaxseed while researchers have stepped up their efforts to find foods or supplements that
It seems contradictory. might keep tumors from starting or spreading, their findings have yet to yield a
In studies of thousands of men, the
risk of prostate cancer is 70 percent slam dunk. Here’s an A-to-Z guide to what they’ve learned so far.
higher in those who consume more
alpha-linolenic acid, or ALA—an
omega-3 fat found in meat, vegetable that was a study done in cell lines, not Demark-Wahnefried suggests several
oils, and other foods.1 (The body may in people or even animals. And they mechanisms to explain why flaxseed
convert ALA to the longer-chain used purified ALA, which is devoid of might work. “The lignans could be act-
omega-3s that are found in fish oil.) antioxidants and is kept at high tem- ing like estrogen,” which slows prostate
“At first we thought that ALA was peratures, not ALA as it is found in the cell growth. “Or they could bind to
associated with a higher risk of prostate body.” testosterone in the GI tract, just as the
cancer because men who consumed Demark-Wahnefried’s studies have beta-glucan fiber in oat bran binds to
more ALA also consumed more meat,” found that flaxseed slows the growth of cholesterol. That would enhance
says Walter Willett, who chairs the prostate tumors in mice.3 “Those testosterone excretion.”
nutrition department at the Harvard results, plus the slower cancer growth But until more research results are in,
School of Public Health in Boston. and the drop in PSA we found in men it makes sense to avoid too much ALA,
“But now it looks like the ALA in oils who ate flaxseed during the month especially from concentrated sources
like soy and canola are also linked to before surgery, are compelling,” she like flaxseed oil supplements.
prostate cancer.” says. “But I wouldn’t stand on a soap- “We found an increased risk of pros-
So it seems surprising that flaxseed, box and tell men to eat flaxseed. We tate cancer in men who consumed
one of the richest sources of alpha- first need well-controlled trials to find 1.5 grams of ALA a day compared to
Photos: VVG/Science Photo Library (top); Nick Waring (bottom).
linolenic acid, lowered PSA levels (from out if it can help.” those who got 0.7 grams,” says Ed
8.5 to 5.7, on average) in a pilot study She has now started a clinical Giovannucci of the Harvard School
of 15 men who were scheduled to have trial that will give a low- of Public Health. Every 1,000 mg of
a repeat biopsy.2 (The men added an fat diet supplemented flaxseed oil in a typical supplement
ounce a day of ground flaxseed to a with flaxseed to cancer contains roughly 500 mg (0.5
lower-fat diet for six months.) patients who are sched- grams) of alpha-linolenic acid.
“The findings are conflicting, but uled to have their pros- His advice: “ALA is a tough
people don’t eat isolated nutrients— tate glands removed. one because we have good
they eat foods,” says researcher Wendy (Most men have to wait evidence that it’s beneficial
Demark-Wahnefried of Duke Univer- several weeks before the for heart disease, but men
sity in Durham, North Carolina. “We surgery can be per- can certainly reduce the ALA
tested the whole flaxseed, which has a formed.) they consume by eating less
host of nutrients—not just ALA, but “Then when the pros- red meat.” That might pro-
lignans, which are fiber-rich plant tate comes out, we can tect the prostate without
estrogens.” measure the cell prolifer- jeopardizing the heart.
A recent study at the University of
Michigan found that ALA promoted
ation rate,” she says.
“That’s more reliable than
prostate cell growth, she notes. “But measuring PSA.” Until researchers know more,
hold off on taking flaxseed oil.
NUTRITION ACTION HEALTHLETTER ■ J U L Y / A U G U S T 2 0 0 4 3
C O V E R S T O R Y
Calcium men since 1986. Those who
reported eating fish more
Calcium is everywhere—fruit juices, than three times a week
breakfast cereals, pancake mixes, and had a 44 percent lower risk
dozens of other foods. You’d never of metastatic prostate can-
guess that too much calcium may raise cer over the next 12 years
a man’s risk of prostate cancer. Yet compared with those who
that’s what several studies show.4 reported eating fish less
“In earlier studies, we saw roughly than twice a month.5 (Fish
four times the risk of advanced prostate oil supplements had no
cancer only in men who consumed at impact on risk.)
least 2,000 mg of calcium a day, com- It’s unclear why fish (a good
pared with men who consumed less source of long-chain omega-3 fats) Green tea slowed the spread of
than 500 mg a day,” says Giovannucci. might protect the prostate, while prostate cancer in mice, but not men.
“But now that we have more precise alpha-linolenic acid (a shorter-chain
measurements, we see that the risk is omega-3 fat) might increase the risk. tea a day (each made with one gram of
roughly double in men who exceed Fish may appear protective because green tea powder) to 42 cancer patients
1,500 mg,” he adds, referring to a new, people who eat more seafood often eat whose PSA levels hadn’t dropped
unpublished study. That’s more than less red meat, which is linked to a despite treatment with hormones.8
the 1,200 mg a day that experts recom- higher risk of prostate cancer in some Their PSAs kept rising.
mend for men, but it’s not much more. studies.6 “It’s hard to tease that out,” “It’s possible that green tea might
How could calcium harm the says Giovannucci. work at earlier stages,” says Jatoi. “But
prostate? Some researchers believe that If meat does promote cancer, it’s not it wasn’t effective in patients with
a high calcium intake lowers levels of clear how. “It could be related to meat advanced cancer.”
vitamin D in the blood. (Taking extra fat, or the nitrites in processed meats, Since then, a study found that
vitamin D doesn’t help.) Less D may or cooking meat at high temperatures,” Chinese men who had prostate cancer
make it easier for cells to lose their nor- he explains. “At this point we can’t say were less likely to be tea drinkers than
mal structure and to proliferate, two for sure.” men without cancer.9 But researchers
hallmarks of cancer cells. He’s more sure about what men need far more evidence to reach any
Photos: StockFood/Susie M. Eising FoodPhotography (top); StockFood/Shipes Shooter (bottom).
“That’s far from proven,” says should eat. conclusions.
Giovannucci. “But there’s no benefit “Only a few studies suggest that fish “It would be wonderful if everything
from getting 1,500 mg or more of cal- may protect against advanced prostate that works in cell lines also worked in
cium a day anyway.” cancer, but it’s still prudent to increase people,” says Jatoi. “We need more
And with the food industry fortifying fish and to decrease red meat to reduce clinical trials to find out.”
so many foods with calcium, consum- the risk of heart disease.”
ing that much isn’t hard. “Ten years Low-Fat Diet, etc.
ago, it wasn’t a problem,” says Green Tea
Giovannucci, “but now you can get a “We put men on a vegan diet of fruits,
lot of calcium from different sources American men are three times more vegetables, whole grains, beans, and soy
without thinking about it.” likely than Japanese men—and 18 products instead of dairy,” says Dean
times more likely than Chinese men— Ornish, describing a study he conducted
Fish vs. Red Meat to die of prostate cancer. Why? with Peter Carroll and their colleagues
One theory is that green tea may pro- at the Preventive Medicine Research
Go with surf, not turf. tect Asian men. When researchers gave Institute in Sausalito and the University
The Health Professionals Follow-up green tea extracts—equal to six cups of of California at San Francisco.
Study has tracked more than 47,000 tea a day—to mice that spontaneously “They exercised three hours a week
get metastatic prostate cancer, it and did an hour of meditation or other
stopped the spread of cancer cells.7 stress-management techniques every
But mice aren’t people. day. They also took part in a weekly
“We tested green tea on men with support group.”
advanced prostate cancer because Ornish studied 90 men who had cho-
we had data showing that green sen to “watch and wait” rather than
tea components were effective have surgery or other treatment for
in killing prostate cancer their early-stage prostate cancer. After
cells in the laboratory,” one year, the men on the vegan diet
explains Aminah Jatoi, an (who were getting 10 percent of their
oncologist at the Mayo Clinic calories from fat) had a small but statis-
in Rochester, Minnesota. tically significant drop in PSA levels,
Jatoi and other physicians while the control group had a rise in
Eating more fish
in the North Central Cancer PSA, Ornish reported at a recent scien-
may protect the
Treatment Group gave six cups of tific meeting. But until the study is
4 NUTRITION ACTION HEALTHLETTER ■ J U L Y / A U G U S T 2 0 0 4
C O V E R S T O R Y
published, the results are difficult to It’s too early to know if Lee is right. “There’s no question that if a prostate
evaluate. But the buzz about selenium may be cancer patient’s PSA goes up quickly—
“It’s encouraging that Ornish saw a causing other problems. say, if it doubles in three to six
drop in PSA,” says Mark Moyad, direc- “We’ve got a population of men months—especially after treatment,
tor of complementary and alternative overdosing on the stuff,” says Moyad. they’re in trouble,” Lee explains.
Medicine at the University of Michigan Too much selenium is toxic, he points “But if you slow down the doubling
Urology Center in Ann Arbor. “But out. “We’ve seen some men showing time, say, from three to four years to
cancer is difficult to fight, especially up with hair loss and dizziness.” (To five to eight years, we don’t know what
when it’s aggressive.” avoid toxicity, don’t exceed 200 mcg a that means. It’s too much of a stretch
When it comes to healthy men, simi- day, the dose used in most studies.) to say that PSA doubling time is a sur-
lar but less drastic diet changes had no “Men should have a blood test before rogate for time to death.”
impact on PSA levels. they start taking a selenium supple- PSA isn’t a perfect measure of a can-
In a four-year study of 1,350 healthy ment to see if their levels are low,” says cer’s growth, says Lee. “If you do noth-
men, researchers at Sloan-Kettering Moyad. “Taking selenium without a ing, PSA can sometimes go up or down.
Memorial Hospital in New York found blood test ignores all we know about For example, bike riding, a biopsy, pro-
that those who ate a low-fat diet (20 the mineral and could be dangerous.” statitis, catheterization, urinary reten-
percent of calories from fat) high in tion, or trauma can raise PSA.”
fiber, fruits, and vegetables had no Soy On the other hand, some researchers
lower PSAs than those who were simply think that traditional soy foods are
given a brochure on a healthy diet.10 The soy story is still unfolding. worth the gamble. “Soy is heart-
Still, says Moyad, any diet that pro- “Prostate cancer rates are low in Asia, healthy and the number-one cause of
tects against heart disease is worth eat- though they’re increasing dramati- death in men is heart disease,” says Lee.
ing. cally,” says Mark Messina, an adjunct But there’s a catch. “The problem
“The worst-case scenario is that you professor at Loma Linda University in with soy is that people get fixated on
only reduce the risk of the number-one California who has consulted for the bars and pills,” says Moyad. “Some
cause of death. We have plenty of men soy industry. bars have 250 calories and some are
who have beaten prostate cancer only high in saturated fat. And they may
to die of something else. The goal is to So far, soy hasn’t cut PSA levels not have the isoflavones and proteins
live long—not to beat just one disease.” in healthy men or prostate that are in traditional soy foods.”
Selenium Tomato Sauce & Lycopene
The good news: the National Cancer “A new study says men who eat ten
Institute is testing whether selenium pizzas a week are less likely to develop
(and vitamin E) can prevent prostate prostate problems,” joked Jay Leno in
cancer in more than 32,000 men December 1995. “They’re more likely
nationwide. The bad news: results to develop size 54 pants.”
are not expected until 2013. It’s been nearly a decade since Ed
Selenium was thrust into the spot- Giovannucci and colleagues at the
light in 1996 when researchers looked Harvard School of Public Health discov-
at its ability to prevent recurring skin “But we have no ered that men who eat tomatoes at
cancers in the southeastern U.S., where large studies in the U.S. because Ameri- least twice a week have a lower risk of
levels of selenium in the soil—and cans don’t eat enough soy.” A recent prostate cancer. Dozens of studies
therefore in locally grown foods—are Asian study suggests that soy protects followed.18
low. the prostate, he adds.13 “Researchers recently looked at all
“In the initial report on the study, Without large numbers of soy eaters the literature and found a 20 percent
they found no difference in skin can- to track, researchers have instead tested reduced risk in studies that looked at
cer, but they noticed a decrease in soy—or isoflavones extracted from cooked, not raw, tomatoes,” says
Photo: StockFood/Leigh Beisch Photography.
prostate cancer incidence,” says W. soy—on PSA levels. (In animal studies, Giovannucci.
Robert Lee of the Wake Forest Univer- the estrogen-like isoflavones curb the Lycopene may explain why cooked
sity Baptist Medical Center in Winston- growth of prostate tumors.) tomatoes seem to be more protective
Salem, North Carolina. Soy failed to lower PSA levels in three than raw. “One serving of tomato
Since then, other studies have found studies on men, and slowed the rise in sauce has much more lycopene than a
a higher risk in men with low selenium PSA in a fourth.14-17 tomato or a glass of tomato juice,” says
levels in their blood or toenails.11 “So far, it looks like not a lot hap- Giovannucci.
“Selenium holds the most promise for pens to PSA when people eat soy,” says Lycopene—the pigment that gives
men who are deficient in selenium,” Wake Forest’s Lee. Many doctors tomatoes, pink grapefruit, watermelon,
says Lee. “In subsequent analyses of the don’t consider a treatment effective and guava their red color—is also an
skin-cancer trial, only those men bene- unless it lowers PSA levels by at least antioxidant that’s concentrated in the
fited from selenium.”12 50 percent. Smaller changes are diffi- prostate gland. When Giovannucci
cult to interpret. looked at men who were older than 65
NUTRITION ACTION HEALTHLETTER ■ J U L Y / A U G U S T 2 0 0 4 5
C O V E R S T O R Y
Meanwhile, Aminah Jatoi and In the SELECT trial, healthy men are
the North Central Cancer taking 400 IU of vitamin E (alpha-
Treatment Group at the Mayo tocopherol) every day for seven to 12
Clinic are testing lycopene in years. That’s considerably higher than
patients with advanced cancer. the U.S. Recommended Daily Allowance
“The dose—30 milligrams a (30 IU), or the 50 IU that seemed to cut
day—is comparable to a diet the risk of prostate cancer in smokers.
with a lot of spaghetti sauce,” she High doses may not be harmless,
explains. In fact, her patients will notes Moyad. “They may increase the
take their lycopene in tomato sauce. risk of bleeding in people who take
She expects results in about two aspirin or other blood-thinning drugs.”
years. In the meantime, says Giovan-
Men who eat nucci, “we don’t have enough evidence Zinc
tomato sauce at least twice a to recommend that men take lycopene,
week have a lower risk of prostate cancer. but we do have enough to recommend “Zinc deficiency results in prostate en-
that they eat tomato products twice a largement…larger supplemental doses,
and had no family history of prostate week.” commonly between 50 and 100 mg
cancer, those with higher blood levels Just remember that you don’t need daily, may help shrink a swollen
of lycopene had roughly half the risk of cheese-heavy dishes like pizza or prostate,” says www.doctoryourself.com.
getting the disease than those with lasagna to enjoy tomato sauce. Yet researchers found more than
lower blood levels.19 double the risk of advanced prostate
“In younger men with a family his- Vitamin E cancer in men who got more than
tory, the risk might be more related to 100 mg a day from supplements, com-
genetics,” he explains. “But those men Vitamin E, once the darling of antioxi- pared with those who got less than
comprise only about 10 percent of peo- dant enthusiasts, has lost its luster 25 mg.21 Either the zinc takers had
ple with prostate cancer, so lycopene when it comes to staving off heart prostate problems to begin with or zinc
may still be protective for the majority.” attacks. “It’s been a bust in studies on damages the prostate.
It’s too early to know, though, more than 55,000 people and cardio- “Zinc is concentrated in the prostate,
whether it’s the lycopene or something vascular disease,” notes the University so some people say that it’s bad if
else in tomatoes that matters. When of Michigan’s Mark Moyad. you’re not getting enough,” says Gio-
researchers recently gave rats a carcino- It’s too early to say whether the vannucci. “But we found an increased
gen, they found fewer prostate tumors antioxidant will prevent prostate can- prostate cancer risk at intakes well
if the animals were fed tomato powder, cer. Most of the promising evidence beyond the U.S. Recommended Daily
but not if they were fed lycopene.20 comes from research in smokers. Allowance,” which is only 15 mg.
“We always inferred that lycopene “Smokers are notorious for low levels “Zinc is a disaster,” says Moyad.
explained the link between tomatoes of vitamin E and other antioxidants,” “Large doses increase bad cholesterol,
and prostate cancer,” says Giovannucci. says Moyad. “What do you tell a non- decrease good cholesterol, suppress the
“Lycopene may be a factor, but it may smoking man about vitamin E? No immune system, interfere with some
also be a marker for something else in one has any idea what it can do in non- bone-building drugs, and potentially
tomatoes that’s beneficial.” smokers.” raise testosterone levels.
“It’s the number-one touted product
for the prostate, and there’s no good
evidence for taking it.”
Journal of Nutrition 134: 919, 2004.
■ Cut back on red meat and shoot for two or three servings of fish a week. 2
Urology 63: 900, 2004.
Urology 60: 919, 2002.
■ Try for at least two servings a week of tomato sauce (preferably on pasta or 4
Epidemiol. Rev. 23: 87, 2001.
other dishes that aren’t smothered in cheese). Cancer Epidemiol. Biomarkers Prev. 12: 64, 2003.
Cancer Causes Control 12: 557, 2001.
■ Take a multivitamin with roughly a day’s worth of vitamin E (30 IU) and Proc. Nat. Acad. Sci. 98: 10350, 2001.
Cancer 97: 1442, 2003.
selenium (55 mcg). 9
Int. J. Cancer 108: 130, 2004.
J. Clin. Oncol. 20: 3592, 2002.
■ Don’t take more zinc than you’d get in an ordinary multivitamin (15 mg). 11
J. Nat. Cancer Inst. 96: 696, 2004.
Photo: StockFood/Lisa Koenig.
BJU Int. 91: 608, 2003.
■ Don’t assume that more calcium is better. Don’t exceed the recommended 13
Cancer Epidemiol. Biomarkers Prev. 12: 665, 2003.
calcium intakes (1,200 mg a day for men over 50 and 1,000 mg a day for 14
Cancer Epidemiol. Biomarkers Prev. 13: 644, 2004.
men 50 and under, from food and supplements combined). Journal of Urology 169: 507, 2003.
Prostate 59: 141, 2004.
■ Until researchers know more about alpha-linolenic acid (ALA), avoid flaxseed Nutr. Cancer 47: 111, 2003.
Cancer Epidemiol. Biomarkers Prev. 13: 340, 2004.
oil supplements. 19
Cancer Epidemiol. Biomarkers Prev. 13: 260, 2004.
J. Nat. Cancer Inst. 96: 554, 2004.
J. Nat. Cancer Inst. 95: 1004, 2003.
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