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YOU ARE WHAT YOU EAT
During this, the last decade of the Twentieth Century, scientists appear
to be locked on “fast forward” in a global quest for the secrets of life
before we cross the threshold into the Millennium. Concepts that
were the science fiction of our childhood are today’s realities.
We’ve met a sheep named “Dolly,” astronomers “saw” a big bang that
could be the birth of a new universe, genetic engineering stories are news
instead of fiction, and medical discoveries and breakthroughs in this country
are coming at a pace previously unimagined.
In the midst of this almost overwhelming information overload, we have
come home to a very simple, basic fact: what mothers have known
intuitively for generations, scientists are now deciphering in the laboratory.
Mother was certainly right on target, for example, about vegetables and
fruit being good for us. As it turns out, we have had access to some
of the most powerful “medicines” in the world to arm us in the war against
cancer...right at the dinner table.
There is some pretty compelling evidence that there are cancer-fighting
substances in everything from “apples to yams.” Everyday fruits and
vegetables contain hundreds of chemicals that work together to help us
fight disease; some are even credited with preventing cancer from forming
in the first place. Some may help the body get rid of cancer-causing
substances that do form, and some starve out wayward cells by cutting off
their vital supply of blood before they can grow into tumors.
We have a whole new lexicon to describe these cancer fighters, with
words like antioxidants, beta-carotene, indoles, lycopenes, nutraceuticals,
and phytochemicals to learn. But, in spite of the volumes of studies
and ongoing research, scientists still don’t know exactly how the chemicals
in fruits and vegetables interact inside the human body to keep us healthy.
In recent years, there has been an almost unending flood of headlines
and hype promoting one food group over another, or touting the properties
of this vegetable or that for “curing” some specific cancer. With
the media solidly on the fresh produce bandwagon, the burgeoning market
for supplements and “turned-on” foodstuffs in this country is estimated
to be a whopping $77 billion a year. It is not especially surprising
that we would be hungry for quick nutritional fixes, since experts figure
that only about one fourth of us bother to eat the minimum daily requirements
for fruits and veggies recommended by the FDA. We have been warned
to take vitamin E to fight heart disease and prostate cancer, to take calcium
to fend off osteoporosis, and vitamin C to keep colds away, so why not
also eat whatever foods that are supposed to fight cancer, too?
What Research
Has Revealed...
For more than 30 years, scientists have been trying to isolate
enzymes that can prevent cancer from forming in the first place.
They have studied patterns in the human population, they have done research
on animals and microorganisms, and they have completed clinical trials
to evaluate the impact of nutritional and lifestyle changes in people.
Some of the studies attracted a great deal of public attention and excitement.
Back in the 1960s, a researcher at the University of Minnesota was studying
what warded off cancer in animals. After switching the animals’ diet
in laboratory experiments, Lee Wattenberg discovered that alfalfa meal
kicked off some kind of enzyme production that afforded the animals some
protection against cancer. More than 15 years later, his group had
also announced the startling fact that indoles — found in broccoli — helped
keep the lab animals free of breast and stomach tumors. President
Bush notwithstanding, the strong flavored, green vegetable suddenly appeared
on dinner tables around the country.
In 1992, a scientist at the University of California at Berkeley reviewed
more than 200 published epidemiological studies and concluded that a diet
high in fruits and vegetables “almost always” cut the risk of a variety
of cancers (e.g., lung, colon and stomach). People who ate the most
of these foods apparently cut their risk in half.
In 1994, scientists at Johns Hopkins School of Medicine isolated a chemical
(sulforaphane) found in broccoli and other cruciferous vegetables that
triggers the carcinogen clean up they had been hoping to find. Even
in reporting the finding, however, the scientists still had insufficient
information to go beyond the advice to eat broccoli — it is good for you.
Whether or not it proves to be better at protecting people
from cancer than other cruciforms has yet to be demonstrated.
What scientists are finding in study after study is that differences
in diet and lifestyles may play a significant role in the prostate cancer
rates in one country compared to another. Consider, for example,
that less than 1 per 100,000 men in Qidong, China is diagnosed with prostate
cancer versus 55 per 100,000 men in Sweden and 102 men in the United States.
Nutrition — of all the risk factors — seems to account for the distinct
difference in the rate of occurrence in countries around the world. While
it is generally agreed that prostate cancer occurs as a result of both
environmental and inherited factors, some experts are going so far as to
estimate that 75 percent of all cases of prostate cancer could be prevented
by changes in diet and lifestyle.
Studying these global differences has produced some intriguing results.
Japanese men have a low incidence of clinical prostate cancer, and they
also appear to have a less aggressive form of the disease if it does develop.
While they have the same 60 percent chance of getting the clinically silent
prostate cancer as their American counterparts, when Japanese men
move to the U.S., their incidence of clinically detected prostate cancer
increases within one generation.
Another startling fact is that countries that have a high incidence
of cardiovascular disease also have a high incidence of prostate cancer.
While no single factor accounts for this, diet appears to be a major variable.
By the 1980s, there was more public awareness about the risk factors for
heart disease, so when people changed their lifestyles accordingly, there
was a corresponding 30 percent decrease in the incidence of heart disease.
If diet modifications proved to be so successful in fighting heart disease,
perhaps the right nutritional prescription will be discovered for
prostate cancer, as well.
Cooking Up Prevention
Let’s face it. We eat a lot of fast food in this country that
is just packed with fat to boost the taste. A lot of the fats we
consume is hidden in vegetable oil, margarine, butter, and processed baked
goods. And then there’s the obvious fat in red meat and snack foods.
Considering the way we eat, few are surprised that there’s an epidemic
of obesity in this country; the number of people clinically overweight
increased 30 percent in the last ten years. Obesity in Japan has
also increased over the past 20 years, and their rate of prostate cancer
has increased markedly, as well.
According to three major national cancer surveys, African American men
have a 34 percent greater chance of being diagnosed with prostate cancer
and a 123 percent greater chance of dying from it than White men.
While the exact reason for this disparity is not known, new studies indicate
that African Americans consume more saturated fat than Whites, Chinese
Americans or Japanese Americans.
Assuming that the mountains of research data are correct, and we can
modify risk factors for cancer and other diseases by changing what we eat,
just what changes do we make? Arriving at a reasonable answer to
this question calls for “digesting” some basic facts about nutrition and
reviewing what researchers are finding in their laboratories...if one can
possibly keep up with the innumerable studies.
Let’s take a look at some prostate “cancer-fighters” that have made
headlines recently:
VITAMIN E — In March of this year
an article appeared in the Journal of the National Cancer Institute suggesting
that 50 mg a day of vitamin E might favorably affect men’s risk for contracting
prostate cancer and from dying of it. The study, however, provided
no proof of such dramatic results publicized by the media. The results
of this investigation (conducted among Finnish men who smoked) contradict
an earlier study of American men which showed no impact of vitamin E at
all. Vitamin E, a fat-soluble antioxidant, does offer some potential
benefits in reducing the risk for heart disease. Vitamin E is inexpensive
and the dose of 50 mg/d has shown no negative side effects, so it probably
won’t hurt those who want to take it.
SOYBEANS are rich in a chemical
which has been found to fight cancer in several ways, most notably by keeping
small blood vessels from forming around cancer cells, cutting off the supply
of oxygen rich blood (angiogenesis) and nutrients the cells need to survive.
Recent research indicates that consumption of soy products may actually
contribute to the relatively low rates of breast, colon and prostate cancers
in the Orient. The staple diet in Japan, for example, contains soy-based
foods like tofu, tempeh and soy milk. The beneficial effect may come
from isoflavones, a plant pigment found in soybeans. Two of these
isoflavones — genistein and daidzein — have been shown to inhibit
the growth of prostate cancer cell lines. In a laboratory study of
immune-deficient mice implanted with human prostate cancer cells, genistein
has been shown to slow tumor growth. The way genistein works is still
under active study, but since it is virtually absent from the American
diet but significant in an Asian diet, it may indeed have cancer-preventing
capabilities.
TOMATOES — A 1997 Harvard University
study reported that men who eat at least 10 servings a week of tomato-based
foods are up to 45 percent less likely to develop prostate cancer.
Based on six years of research into the dietary habits of 47,000 men in
health professions, between the ages of 40 and 75, the study announced
in the Journal of the National Cancer Institute that pizza, spaghetti sauce
and other foods rich in tomato substantially lowered the risk of prostate
cancer.
While spaghetti sauce was the most common tomato-based food on the men’s
diet, the benefits appeared to come from eating tomatoes raw, cooked, as
a juice, or in a sauce — even made into catsup or when cooked on a pizza.
Tomatoes are rich in lycopene, another anti-oxidant, as well as in vitamin
C. Earlier studies had found that prostate cancer was less common
in southern Mediterranean countries, where tomato-based foods appear on
every table. Tomatoes also contain p-coumaric acid and cholorogenic
acid which bond to nitric oxides and flush them out of the body before
they can form cancer-causing nitrosamines. Watermelons, red peppers
and carrots also contain lycopene, and green peppers, strawberries and
carrots contain the beneficial acids.
CRUCIFERS (BROCCOLI ET AL) — Study
after study have shown these strong-tasting veggies — broccoli, cabbage,
Brussels sprouts, kale, cauliflower — to have cancer-fighting properties.
They contain a compound that inactivate cancer-causing chemicals and some
also contain compounds that affect estrogen metabolism. Most of the
crucifer research has been associated to breast or colon cancer, and there
is no specific evidence that a diet rich in these vegetables will decrease
the risk for or prevent prostate cancer. Nevertheless, they should
certainly be a part of any general dietary program for cancer prevention.
GARLIC & ONIONS — No one is
quite certain why garlic may inhibit tumor growth in humans and in animals,
but its extracts have been found to accomplish this in culture. Garlic,
onions — and its close relatives leeks, shallots and chives — contain some
compounds that have been associated with lower incidence of gastric and
colorectal cancers. Garlic is one of the oldest natural medicines
known to man and can be eaten in meals prepared for just about any diet
program. People living in China’s Shandong Province who eat large
amounts of garlic and onions are said to cut their risk of stomach cancer
by as much as 40 percent. Here at home, 41,000 women in an Iowa study
who added garlic to their daily menu, cut their risk of colon cancer by
35 percent. Garlic has not, however, been proven in the laboratory
to prevent either cancer or heart disease.
GREEN TEA is another staple in Asian
diets, so drinking it may be another reason why they enjoy lower cancer
rates. Under an American Institute for Cancer Research grant, scientists
at Case Western Reserve University, Ohio, are exploring the effect of green
tea on prostate cancer. Apparently, the green tea leaves contain
antioxidants called polyphenols which may prevent damage to DNA.
One group of polyphenols — catechins — seem to prevent cancer cells from
multiplying if they do form, and help speed them out of the body.
One research study did show an increased risk of esophageal cancer among
tea-drinkers though, and scientists put the blame for this on the habit
of drinking the beverage boiling hot. Let it cool off, first.
While the scientists sort out all their antioxidants and
lycopenes,
and search for new strategies to use diet and lifestyle modifications to
prevent the progression of prostate cancer, there are some basic nutritional
concepts that can be incorporated into just about anyone’s diet.
You can’t go wrong if you: 1) eat no more than 20 percent of your
daily calories as fat; 2) eat at least 25 grams of fiber a day to ward
off bacteria and sweep cancer-causing substances out of the body; and,
3) eat five to nine servings of fruits and vegetables every day. Remember,
the goal is to change for life so that unhealthy eating habits disappear
altogether. |
