How Foods Can Prevent Breast Cancer

Excerpted from
The Breast Cancer Prevention Diet : The Powerful Foods, Supplements, and Drugs That Can Save Your Life
By Robert Arnot, M.D.

Chemoprevention

There have been four standard ways of treating cancer: radiation, chemotherapy, surgery, and biological therapy. Now emerging is a new and far more important technique, chemo- prevention. Chemoprevention allows you to prevent a cancer from growing in the first place or to treat a preclinical cancer. Many of you are familiar with this idea from Pap smears that have come back abnormal but not cancerous. They may show "dysplasia" but not cancer. Early treatment prevents cancer. We know that a breast cancer could take as long as 33 years to develop. For much of that time it is unseen and undetectable by standard methods. As an example, in their forties, 40 per- cent of women have small cancers in their breast that escape detection, according to autopsy reports of women who died from other causes. Only when the tumor reaches one billion cells in size can a mammogram detect it; that's the smallest that a radiologist can see but it is simply enormous in terms of cancer growth. What this book is designed to do is change the biology of your breast so that you create a very unfavorable climate for a cancer to grow. Here's how.

Cancer is often treated with a variety of chemical agents to target the cancer's life cycle in as many ways as possible. Because of our great daily familiarity with foods, we tend to discount their ability to work as medicines. But look at the proven ways in which foods can act to target cancer development. They can:

• disrupt hormonal pathways that cause cancer
• repair the genetic material DNA
• inactivate harmful chemicals
• inactivate enzymes that drive chemical reactions
• scavenge mutant cells
• lower oxidant levels with antioxidants
• inhibit tumor growth

- basically the entire tool chest needed to stop a cancer before it starts. And fighting cancer requires a big tool chest.

This chapter will show you how you can block the estrogen effect in a step-by-step fashion with the right kinds of foods. Remember that the key principle of cancer chemotherapy is to use several different agents to interrupt the cancer cell's growth with several critical choke holds. The same concept applies before a cell becomes cancerous, using multiple agents to block the amount of estrogen that flows through the blood-stream and attaches to estrogen receptors in the breast.

You will find that many of these steps can be targeted with more than one nutritional strategy. Some of the same strategies such as high-fiber or low-fat diets affect more than one step because they have more than one anticancer action. You'll find each of these measures covered at length in a chapter of its own. There's a lot of science in this chapter. Don't be overwhelmed by it. In the end, it all comes down to blunting the estrogen effect and blocking the trigger that causes cancer. As you'll see in the last part of the book, the diet itself is pretty simple. I include the science because knowledge leads to tremendous empowerment and because it will allow you to change and adapt your diet as new discoveries are made. The more you know about what you are doing to your body, the more likely you are to succeed.

Slow Down Estrogen Production

How useful is the idea of decreasing the effect of estrogens? R. L. Prentice, in Cancer Causes and Control, estimates that a 17 percent reduction in the key estrogen, estradiol, might produce a four- to fivefold reduction in breast cancer. In other words, small changes in estrogen levels can effect large changes in the risk of cancer. Let's look at the most effective steps.

Low-Fat Diet

A low-fat diet is eaten in those countries, such as China, Japan, and Singapore, with the lowest incidence of breast cancer.

Countries with higher-fat diets - these include England. Scotland and Wales, and Finland - have more breast cancer. For instance, Finnish women on higher-fat diets had higher estradiol levels than Asian women - and for higher breast cancer rates. In fact, if there is one common denominator found in Asian women with low risk of breast cancer, it is a low level of estradiol. Remember that estradiol is the most important and powerful of the natural estrogens. A high-fat diet increases estradiol production by 30 percent. In dozens of animal experiments, a high-fat diet spurs the growth of cancers. But the connection between low fat and low estrogen levels isn't just an observation, it is something that works in real life. The British Journal of Cancer showed that a 15 percent low-fat diet, followed rigorously for two years, lowered estradiol levels by 20 percent.

High-Fiber Diet

Hand in hand with a low-fat diet is a high-fiber diet. Americans pay great lip service to fiber but eat vanishingly little of it by world standards. However, when the American Health Foundation made a real effort to increase fiber intake substantially, even they were surprised by the results: The more wheat bran patients ate, the lower their blood levels of estrogen were. After just two months of a 20-grams-per-day wheat bran supplement, estradiol decreased significantly. But the addition of high fiber to low fat is especially potent medicine. African-American women have far higher levels of estrogen than Caucasian women. Their high-fat, low-fiber diet is held accountable. Doctors at Tufts University fed African-American women a 40-grams-per-day high-fiber diet combined with a 20 percent low- fat diet. Estradiol fell 8.5 percent and estrogen sulfate, the most prevalent estrogen, fell by 22 percent. This same high-fiber, low-fat diet works wonders for millions of women trying to control excess body fat.

Lower Body Fat

Excess body fat works as an enormous estrogen factory. The more fat cells and the bigger they are, the more estrogen they produce. As many women gain weight, those who gain it "up top," that is, in their breasts and upper abdomen, add the greatest risk. Obesity is associated with poorer survival in women who contract cancer. The less body fat you have, the less estrogen you will produce. When studying Japanese women, scientists hypothesized that a big part of the reduced risk of cancer they see in a low-fat diet simply comes from having less fat and therefore less estrogen. Keeping body fat low is especially important as an adult. Weight gain from early adulthood may account for as much as a third of new cases of postmenopausal breast cancer.