The Connection Between Diet and Cancer
For women, good eating habits may be key in fighting breast cancer, and for men, a new herbal remedy may have some success against prostate cancer, according to findings announced by the American Institute for Cancer Research (AICR) at its 10th annual research conference in Washington D. C.
For 25 years, scientists have believed that cancer must be preventable because of the worldwide differences in cancer occurrences, according to Dr John Potter, Head of the Cancer Prevention Research Program at the Fred Hutchinson Cancer Research Center and Professor in the Department of Epidemiology and Community Medicine at the University of Washington.
As data grew, so did suspicion that certain dietary elements and handling methods caused increased cancer risk in humans. For example, known carcinogens arise in food as a result of certain cooking, processing, or storage methods:
- heterocyclic amines in MEAT COOKED AT VERY HIGH TEMPERATURES
- polycyclic aromatic hydrocarbons occur in cooked foods EXPOSED TO SMOKE
- aflatoxins found in MOLDY FOOD
- N-nitroso compounds in CURED and SPOILED FOODS and ALCOHOLIC DRINKS
Dr. Potter cites evidence that diets high in fruits, vegetables, whole grains and beans have the potential to "short-circuit" the cancer process at several different stages. Certain enzymes are known to allow the body to detoxify and excrete toxic and carcinogenic compounds. A variety of components in vegetable and fruits "turn on" those enzymes. Research also reveals how factors such as high meat intake, lack of exercise, obesity and smoking encourage cancer growth from the body.
Diet Affects Cancer Occurrence
Soy helps fight both prostate and breast cancer because they involve hormones. Soy contains natural plant estrogens. For example, Asian women, who consume large amounts of soy, have very low rates of breast cancer compared to Western women. When Asian women emigrate to western countries and consume Western diets, their breast cancer rates rise. It is not yet understood how soy prevents tumor growth.
Other evidence that diet affects cancer occurrence:
Fat is directly linked to the risk of prostate cancer. Research suggests that it increases testosterone production, and prostate tumors need the hormone to grow. One study has found that high saturated fats may be a factor in whether prostate cancer reaches advanced stages.
AICR believes that 60% to 70% of all cancer could be prevented through a combination of sensible diet, maintaining a healthy weight, physical activiy and not smoking.
Breast Cancer Findings
Highlights include findings that suggest a woman's diet during childhood has greater impact on her breast cancer risk than diet during adulthood. One out of eight American women will develop breast cancer. Although family history is a factor that can increase the risk of breast cancer, researchers estimate that only five to ten percent of breast cancers can be attributed primarily to genetic factors.
During childhood, high estrogen levels -- linked to high body mass and high-fat diets -- seem to play a powerful protective role against breast cancer, according to Dr. Leena Hilakivi-Clarke of the Lombardi Cancer Center at Georgetown University in Washington D.C. The research suggests that estrogen exposure during childhood may cause changes in the number and type of hormone receptors, resulting in lowered lifetme cancer risk. However, the research is too new to make responsible dietary recommendations.
It is possible that estrogen exposure during childhood may cause changes in hormone receptors, lowering lifetime cancer risk.
Prostate Cancer Findings
Another surprise announcement concerns successful treatment of prostate cancer. The prostate is the gland that produces semen, the fluid that carries sperm. It is not essential for sexual activity, but only for reproduction. After skin cancer, prostate cancer is the most commonly diagnosed cancer in American men; an estimated 37,000 die from prostate cancer each year. African-American men have a significantly high incidence of prostate cancer than Caucasian American, Hispanic American, Native American and Asian American men.
An over-the-counter mixture of eight Chinese and American herbs has had success as a treatment for prostate cancer, according to Dr. Jan Geliebter of New York Medical College. The herbal treatment, called PC-SPES, has caused decreases in the prostate specific antigen (PSA) levels of prostate cancer patients. PSA levels are used to gauge the extent of prostate cancer, but are only an indicator of the disease. Further, it has reduced tumors by about 40% in animal studies and strongly inhibits the growth of prostate cancer cells in human tissue culture, according to Geliebter.
PC-SPES is a food supplement containing eight plant species: Isatis, Licorice, Lucid ganoderma, Pseudo-ginseng, Rubescens, Saw palmetto and Scute.
"The interesting thing about PC-SPES research is that it's proceeded in such an upside-down direction," says Geliebter. "It began with humans and moved into the laboratory. Usually, you start in the lab and only graduate to human studies. So here we are, with a substance showing real world potential, and we still don't know precisely WHY it seems o effective. That's the next step."
PC-SPES research began after doctors reported that prostate cancer patients who were taking the herbal remedy "felt better."
Interview with Dr. Bernadine Healy, president of the American Red Cross
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Is the diet-cancer connection well-established science? Or are these findings on the "fringe?"
The official line of the American Cancer Society recommends five servings of fruits & vegetables per day; limit fat and alcohol intake.
It has been studied in some patients and in the lab. It has been shown to have biological effect, similar to a compound used to treat prostate cancer (LUPRIDE) -- male version of TOMOXIFEN (anti-testosterone effect). These data demonstrate that "unregulated commercially available dietary supplement that can affect diseases, standard medical therapy and general health." The fact that it works is good, but it should be put through the same rigorous study of any other cancer drug. Just because it's an herb, you still need to know toxicity level & dosages.
Quite honestly, this study reinforces information that has been available for a couple of years. The new data is that it is effective on cultures in the lab.Does this mean if you have prostate cancer, you should take this remedy?
Absolutely not. It should be subjected to the same rigorous studies that chemotherapy is. This is an area of treatment, not prevention. When you start using herbs that have powerful biological effects, and you are getting treatment already, YOU COULD BE DOUBLE-DOSING YOURSELF.
Finally we are recognizing that diet can play a role - that what we eat - can increase and decrease our risk for cancer. Numerous studies have focused on this in the past decade and no one would consider that the link between the diet and cancer is on the fringe. This is now art of mainstream. But that doesn't mean that EVERY link you hear about is legitimate. The breast cancer announcement seems to imply that high estrogen levels, usually accompanied by high body mass and high-fat diet, could be advantageous during childhood for girls. Isn't this contrary to conventional wisdom?
On the face of it, yes. These are surprising results and probably have to be studied in depth. We have to learn more about it. Remember this is an observation.What can adult women do to reduce their breast cancer risk, regardless of what they did in childhood?
What we know is that there are nutritional factors that can decrease risk: five servings of fruits & vegetables per day. Have a lower fat diet. CUT OUT ALCOHOL. I think most women don't understand that, how many women know that?
This isn't like heart disease where diet can reduce chance by up to 50%. It's related to being a woman, related to internal metabolism, related to life exposue to estrogen, and how her body handles estrogen. Regarding soy, the benefits accrue over a lifetime, not from taking soy when your 40.What about the french study showing advantages of alcohol?
That's cholesterol. You may live longer. But even moderate drinking has a small effect on your breast cancer risk.Both of these findings on breast cancer and prostate cancer talk about hormonal changes caused by diet. How new is the finding that compounds in foods can affect our hormones?
It's not new, but it's not well known. A perfect example is that many plants contain phyto-estrogens which are plant hormones which have a mild hormonal effect in humans who consume them. An excellent example is soy and soy products. There is some evidence that a diet high in soy as in Japan, might explain low incidence of prostate and breast cancer in that population. However, we're talking about a LIFETIME dietary pattern, not an occasional soy milk shake or tofu pie.Compared to breast cancer, prostate cancer is relatively new on the national health consciousness. Yet it has been linked to the same gene as breast cancer. Can you explain briefly what it is?
Actually, there is more than one gene in common with breast cancer. Prostate cancer also tends to run in families
The prostate is a walnut sized gland at the base of the penis. It produces sperm, and it is sensitive to hormones, particularly testosterone. As men grow older, they have increased chance of cancer in that gland. Prostate cancer and breast cancer have many interesting similarities such as:
And by the way, prostate cancer is now the number two cancer diagnosed among American men.Will these herbal remedies interfere with conventional cancer treatment?
It has effects shown similar to LUPRIDE, commonly used in treating prostate cancer. The concern is that if you use both, you could get into the toxic realm. Go with the one that is better studied. If you are considering trying this herbal remedy TELL YOUR DOCTOR. There is no evidence that this herbal remedy is as good as chemotherapy. Should people be taking this herbal remedy to prevent prostate cancer? It causes impotence and breast swelling, some pretty powerful side effects, it is not likely to be appealing to many men.African-American men are more likely to develop prostate cancer than other ethnic groups of american men; are their hormones uniquely susceptible?
We don't know why. The interesting thing is that African-American women are LESS likely to develop breast cancer. A curious discordance.Putting diet aside for a moment. There is a theory that increased rates in both breast cancer and prostate cancer are due to evolution (omen were not meant to endure the constant hormonal stress of menstrual cycles, and men were not meant to have sex beyond their prime)
Interesting theory. The reality is, at the turn of the century people didn't live much above 50, so we didn't see as much. If scientists know that certain dietary factors can fight cancer, why isn't there a mega-supplement for all of us to take?
That sounds easy, but there is not likely to occur in the future a "magic bullet for cancer prevention or any thing else.