Food for Life: How the New Four Food Groups Can Save Your Life (15 page)

Just as countries differ markedly in the prevalence of breast cancer, this hormone-related cancer varies in exactly the same way. Asian and Latin American countries have a much lower prevalence of prostate cancer, while it is very common in Europe and America. Ten men die of prostate cancer in Western Europe for every one who dies in Asia.
³⁵

Cancer of the prostate is strongly linked to what men eat. Again, animal products are consistently indicted. Milk, meat, eggs, cheese, cream, butter, and fats are found, in one research study after another, to be linked to prostate cancer.
^36–
45
, And it is not just dairy products and meats. Some studies have also pointed a finger at vegetable oils.
^3
,
37

Who has a lower risk? Countries with more rice,
³⁶
soybean products,
⁴³
or green or yellow vegetables
^46
,
47
in the diet have far fewer prostate cancer deaths. Vegetarians have less prostate cancer.
²
Scientists have long been interested in members of the Seventh-day Adventist church because of its vegetarian tradition. Adventist men have only one-third the prostate cancer risk of other men,
⁴⁸
although Adventists also generally avoid tobacco, alcohol, and caffeine. Some evidence suggests that becoming a vegetarian in
adulthood is helpful, but those who are raised as vegetarians have the lowest risk.
⁴⁹

How does a Western diet cause cancer? The prostate is very sensitive to hormones. As we saw in
Chapter 1
, men who consume diets based on animal products tend to have more testosterone and more estrogens, compared to men who eat healthier diets. This increase may be due to overproduction in the body or, because fiber in the diet is essential for the normal excretion of sex hormones, they are less able to get rid of them. The higher levels of these hormones make them the chief suspects in the epidemic of prostate cancer.

The protection that seems to come from including vegetables and fruits in the diet may be that every bite of broccoli is not a bite of beef. But, in addition, vegetables supply vitamins that are well-known cancer fighters, as we will see later.

The colon is another name for the large intestine—that is, the second half of the digestive tract. The colon is assaulted day after day by our dietary indiscretions, and colon cancer can be the result.

The public already knows about the role of diet in colon cancer. Strong links have been found between the consumption of meats and other fatty foods and colon cancer.
^2
,
50
,
51
When the past diets of cancer patients are studied, it is very clear that meat-based Western diets are linked to cancer. And comparisons of countries with different rates of colon cancer have supported this finding.

In order to absorb the fats that we eat, the liver makes bile that it stores in the gall bladder. After a meal, the gall bladder squirts bile acids into the intestine, where they chemically modify the fats we have eaten so they can be absorbed. Unfortunately, bacteria in the intestine turn these bile acids into cancer-promoting substances called
secondary bile acids
. The problem with meats is that they contain a substantial amount of fat, and foster the growth of bacteria that cause carcinogenic secondary bile acids to
form. In addition, when meat is cooked, carcinogens form on its surface.

Happily, high-fiber diets offer a measure of protection.
²
Fiber-rich whole grains have a protective effect, as breakfast cereal commercials remind us. Fiber greatly speeds the passage of food through the colon, effectively removing carcinogens. And fiber has another interesting effect: it actually changes the type of bacteria present in the intestine, so there is reduced production of carcinogenic secondary bile acids. Fiber also absorbs and dilutes bile acids.

This humble part of the diet was largely ignored until a brilliant surgeon, Dr. Denis Burkitt, demonstrated the value of fiber, not only to protect against colon cancer but for dealing with a whole range of health problems. When the Physicians Committee for Responsible Medicine proposed the New Four Food Groups in 1991, Dr. Burkitt came to Washington to support the plan. Physicians have been very busy using surgery, chemotherapy, radiation, and other treatments to mop up the flood of disease, when the key, Dr. Burkitt said, is to stop the flood at its source: diet.

Even people who are at particular risk for cancer can be helped by a high-fiber diet. Jerome J. DeCosse, a surgeon at Cornell Medical Center, gave bran to patients with recurrent polyps of the colon. These are small growths that have a tendency to become cancerous. DeCosse found that within six months, the polyps became smaller and fewer in number. He believes that pentose fiber, which is plentiful in wheat, is the key to bran’s power.
⁵²

Grains are not the only plant foods that help protect against colon cancer. Scientific studies have shown that populations consuming generous amounts of vegetables, particularly cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, and cabbage, also have a lower risk of colon cancer.
²
Precisely why this is so is not clear, but it seems to relate both to their fiber content and to specific cancer-fighting compounds they contain.

Other cancers of the digestive tract are also linked to dietary factors. In cancer of the esophagus, alcohol increases the risk, and alcohol and tobacco together exert a synergistic effect. Pickled foods and very hot beverages also increase risk, while fruits and vegetables reduce it. Stomach cancer is linked to smoked and salt-pickled foods, and again vegetables seem to have a protective effect. Liver cancer is linked to a carcinogenic chemical called aflatoxin, which is produced by a mold that grows on peanuts and corn. This disease is uncommon in most Western countries, but is very common in sub-Saharan Africa and Southeast Asia, where the mold is common. Pancreatic
cancer has been linked to consumption of alcohol, coffee, and meat.
²

Two themes consistently emerge from studies of cancer in many sites: vegetables and fruits help reduce risk, while animal products and other fatty foods are frequently found to increase risk.

Unfortunately, the terms
fiber
and
fat
tend to obscure the real dietary issues. People tend to think that fiber is something that one shakes out of a box when, in fact, fiber is found in whole grains, vegetables, fruits, and beans. (There is no fiber in any product from an animal.) So when you hear of the merits of fiber, think of whole-grain bread, rice, vegetables, fruits, and beans. And when you hear of the dangers of fats, think of meat-based diets aided and abetted by oily foods.

As we saw in
Chapter 1
, as oxygen is used in the body, some of the oxygen molecules become unstable and are called free radicals. These unstable oxygen molecules can attack cell membranes and can damage the DNA in the nucleus of the cell. It is this damage to DNA that is the beginning of cancer.

Natural chemicals called antioxidants, which neutralize free radicals, also help reduce cancer risk. Vitamin C, vitamin E, beta-carotene, selenium, and many other antioxidants are provided by a diet rich in vegetables, fruits, and grains.

People who include fruits and vegetables in their daily diets have lower rates of many forms of cancer, including lung, breast, colon, bladder, stomach, mouth, larynx, esophagus, pancreas, and cervix.
⁵³
Effects have even been seen in childhood. When children with brain tumors were studied, it was found that their mothers consumed less vitamin C during pregnancy, compared to other women.
⁵³
Again, there are many factors outside diet that contribute to cancer, from chemicals to radiation, but vegetables and fruits help counteract even these factors to an extent.

Even with vegetables and fruits in the diet, damage to the cellular DNA will occasionally occur. So the body has built-in repair machinery. Fixing DNA requires a B vitamin called
folic acid
, which is found in dark-green
leafy vegetables, fruits, peas, and beans. The Recommended Daily Allowance of folic acid for adults is 400 meg per day. As
Table 6
below shows, beans and vegetables supply plenty of folic acid.

Table 6     
Folic Acid in Foods

Smokers have provided dramatic demonstrations of the power of vegetables and fruits. A fifty-five-year-old male smoker whose diet is low in vitamin C has a one-in-four risk of dying of lung cancer in the next twenty-five years. But if the smoker has a high intake of vitamin C, either through diet or supplements, his risk drops to 7 percent.
⁵⁴

People who quit smoking benefit from fruits and vegetables, too. Researchers at the University of Texas found that former smokers who do not eat many vegetables and fruits are five and a half times more likely to develop throat cancer compared to ex-smokers who eat more fruits and vegetables.
⁵⁵
Even those who are at high risk for cancer—for example, asbestos workers who smoke cigarettes—are protected somewhat when their diet includes foods rich in beta-carotene.

The point is this: We are all exposed to cancer-causing chemicals, whether we like it or not. Some people are smokers, and, of course, quitting smoking is vital. But all of us are exposed to chemicals in the air, in the water, in our food, and in the household products we use, not to mention the carcinogens produced within our bodies as a part of our metabolic processes. While
trying to minimize our exposure to carcinogens, we can also shore up our defenses against these assaults by including vegetables and fruits in our routine.

It is not just the vitamin C, beta-carotene, vitamin E, or fiber that makes these foods so powerful for health. It is these combined, and others besides. We are now at the point where it no longer makes sense to recommend just a beta-carotene-rich diet, or a vitamin C-rich diet, or a vitamin E-rich diet. What we need is a diet rich in vegetables, fruits, grains, and legumes, because every day we find more reasons why these foods are so powerful for health.

As we noted in
Chapter 1
, iron is a catalyst for the formation of cancer-causing free radicals. Gone are the days when nutritionists preached that the more iron there is in the diet, the better. Iron encourages damage to DNA, which can lead to cancer. “Iron is known to be a key catalyst for this process—one of the best catalysts you can imagine,” said Harvard biochemist Dr. Randall Lauffer. “The body tries to safely sequester iron away in the cell and keep it away from the DNA.” Of course, the body does need iron. But beyond the rather small amounts the body needs, iron becomes a dangerous substance, making DNA damage more likely.

In addition, cancer is a disease of uncontrolled cell division—cells dividing over and over, forming a tumor and sending cells to other parts of the body. Iron plays a role here. It is essential to cell division. “If the cell doesn’t have iron around, it simply does not divide,” Dr. Lauffer said. “So if you can restrict the amount of iron to a cancer cell, it actually slows down cancer growth.”

Research has borne out that higher amounts of iron in the blood can mean higher cancer risk. “There are several studies in foreign countries and one very large study in this country with over 10,000 people examined,” Dr. Lauffer said. “For men especially, it was clear that higher iron levels were associated with increased risk for certain forms of cancer. Iron-overload victims have an increased cancer risk. For example, a person with inherited iron-overload has 200 times the risk of liver cancer compared to a normal person.”

A menu based on the New Four Food Groups keeps iron at a safe level.
On the other hand, meats encourage too much iron absorption.
Chapter 1
gives details on how to determine your own iron status.

There is one final piece to add to the cancer prevention puzzle: immunity. In spite of our best efforts, cancer cells will arise in the body from time to time. Left to their own devices, these cells will multiply and spread. Luckily, we have “soldiers” that roam our bloodstreams looking for these troublemakers. These are the
white blood cells
. Some of them, called
natural killer cells
, are the foot patrols that seek out and destroy cancer cells and bacteria. They engulf and destroy aberrant cells before they can cause damage.

Like soldiers everywhere, they are not always given the very best rations. Some foods strengthen them, and others slow them down. It turns out that our natural killer cells work best when they are getting a healthy dose of beta-carotene—rich foods. The effect of beta-carotene on blood cells is dramatic. It significantly increases the percentage of cells in the body acting as natural killer cells and as T-helper cells,
⁵⁶
which are a type of white blood cell that acts like an officer directing a battle plan. (Their name comes from the fact that they are conditioned by the thymus, a gland in the upper chest.) The effect of beta-carotene on these cells has been demonstrated both in human volunteers and in laboratory tests on blood cells.
⁵⁷
Although vitamin A can be made from beta-carotene, the immune power comes from beta-carotene itself. The vitamin A packed into vitamins or contained in meats lacks much of the immune-boosting power of beta-carotene.