Don't Let Your Diet Add to Your Cancer Risk
PART I – CANCER AND FOOD
Food Choices and Cancer Risk
Some foods seem to help our bodies fight off cancer before it starts, while other foods can compromise our immune systems, thereby raising our risk of getting cancer and/or of dying from it. Much research is being done trying to find the specific components of foods that do each of these, but it may be also useful to focus on the foods themselves, creating one set of foods to seek to consume more of, and a second set to avoid as much as possible. Because we have to eat to survive, it is hard to accept that some foods may increase our risk of getting cancer. Without any food we starve to death in a relatively short period of time. Cancer is a slowly progressing disease. If there were no choice of food, it would of course be foolish to avoid cancer-risk-raising foods if the alternative is malnutrition. That is not the case for those of us fortunate enough to live in this land of plenty, with overweight and obesity epidemic. We have choices, and many people are making the wrong choices too often, resulting in as our rising cancer incidence.
Some of the foods we ought to seek to avoid are very commonly eaten, and it is sometimes shocking to hear this. One response is often that if these foods are so risky why doesn’t everyone who uses them get cancer. The fact that the risk of an American getting cancer in his or her lifetime is about 1 in 2 is astounding, yet doesn’t seem high enough to convince some that these common foods are a factor. To those people I offer the reminder that smoking increases risk of lung cancer tremendously, yet not everyone who smokes gets lung cancer. On the other hand, remember that some cases of lung cancer occur in non-smokers. There are no guarantees, but there is genuine risk reduction.
Plant Foods versus Animal Foods
Overwhelmingly, studies have found that cancer risk is lowered by increasing consumption of foods from plants, especially fresh vegetables and fruits; and by decreasing consumption of animal products, such as dairy, meat, and eggs. Many people, including many health professionals and cancer societies, believe the fat in animal products is the key cause of diet-linked cancer, however a scientific review found:
“There is a link between animal protein and cancer, evident in both laboratory and human epidemiological studies”. (Journal of Surgical Research 59(2), (1995), pp. 225-228.)
Thus it is the protein, not just the fat that is a risk factor. Since animal products are largely composed of protein and fat:
The Story of Jane Plant
Dr. Jane A. Plant, chief scientist of the British Geological Survey, was diagnosed with breast cancer in 1987. Six years (and five operations) later she was told the cancer had spread uncontrollably, and was given just a few months to live. She spent those next months researching the subject of diet and breast cancer, changed her diet radically according to what worldwide evidence showed was associated with lowest risk of the disease. Within several weeks her cancers started disappearing, and within a few months she was cancer-free according to all tests. Over the next 12 YEARS she wrote several books, including Your Life in Your Hands: Understanding, Preventing and Overcoming Breast Cancer (New York: Thomas Dunne Books, 2001) and the No-Dairy Breast Cancer Prevention Program. (London: Virgin Publishing, 2000) The crux of her diet is elimination of all dairy products and the meat from all dairy cows, which is most of the cheap ground beef sold in the U.S., Canada, and Europe.
Countries like China, which don’t use dairy products or meat from dairy animals, have very low rates of breast (and prostate) cancer. “The figures for the chances of women in China dying from breast cancer are one in ten thousand, as opposed to close to one in thirty-three for the U.S. For prostate cancer, the difference is even greater.” (The New Optimum Nutrition Bible, Patrick Holford. Berkeley: Crossing Press, 2004. P. 64).The explanation for this connection is that the growth hormones that cow’s manufacture to put into their milk to help their calves grow quickly, target certain organs in adult human tissue (breast in women and prostate in men) causing unnatural growth (cancer).
In response to all of the questions Dr. Plant received about risk of osteoporosis from not drinking milk, she researched and wrote another book Understanding, Preventing and Overcoming Osteoporosis (London: Virgin Books Ltd., 2004). In that book she concluded that dairy products are not necessary to maintain strong bones (again, countries like China, where milk is not used, have low rates of osteoporotic bone fractures). In fact, as long ago as 1987, a Mayo Clinic study concluded that insufficient dietary calcium is not a major cause of bone loss. And the Nurses’ Health Study in 1997, surveyed food habits of over 120,000 women, and concluded that milk-drinking did not decrease bone fracture rate (American Journal of Public Health, Vol. 87, pp. 992-997.)
Jane Plant concluded: “Undoubtedly, the best anticancer diet would be completely vegan: strictly vegetarian, with no meat or dairy products.”
Your Life in Your Hands: Understanding, Preventing and Overcoming Breast Cancer, Jane A. Plant. New York: Thomas Dunne Books, 2001, pg. 122.)
Hormone –Related Cancers : Breast, Prostate, and Ovarian - Is the Risk Increased by Dairy and Other Animal Products?
Excess dairy and other animal product intake have been stated to be a strong risk factor for hormone-related cancers like breast and ovarian cancer in women and prostate cancer in men. An excellent book about this cancer-animal protein connection is The China Study (Dallas: BenBella Books, 2006) by Cornell University Nutrition Professor T. Colin Campbell. An article by Dr. Dean Ornish in the Journal of Urology (September 2005), documents reversal of prostate cancer indicators by elimination of dairy and other animal products.
Below are a collection of quotes from the medical/scientific literature that rarely find their way into popular media:
There is a similarity in causation of breast cancer and prostate cancer as indicated by the fact that: Men with a family history of breast cancer have an increased risk of prostate cancer, and women with a family history of prostate cancer have an increased risk of breast cancer. Epidemiology 9 (5) (1998), pp. 525-529.
Thus the following observations with one cancer or the other can likely be extended to encompass both:
---A massive international study that contained data from 59 countries showed that men who ate the most meat, poultry and dairy products were the most likely to die from prostate cancer, while those who ate the most unrefined plant foods were the least likely to die from this disease. Journal of the National Cancer Institute 90 (21) (1998), pp. 1637-1647.
---As animal-derived food intake increases from once a week to four times a week, breast cancer rates increase by 70%. Japanese Journal of Cancer Research 85 (1994), pp. 572-577.
---A British study found low death rates for breast cancer where dairy product consumption was low, even when intake of other fats was high. British Journal of Cancer 24 (1970), pp. 633-43.
---Studies that have failed to show a relationship between animal product consumption and breast cancer suffer from methodological problems. Journal of the National Cancer Institute 89 (1997), pp. 766-775.
Note: Insulin-like Growth Factor-1 (IGF-1) is a growth hormone produced by all mammals. Levels of it are very high in dairy products and in beef products made from the flesh of dairy cows, since these animals are bred to grow very quickly, and to produce a lot of milk so their calves can grow quickly.
---In a study of 700 men, 233 of whom were vegan, serum IGF-1 was 9% lower in the vegans. British Journal of Cancer 83 (1) pp.95-97.
---In a study of men with prostate cancer, it was found that on average their serum IGF-1 was 8% higher than matched controls without active prostate cancer. Science 279 (1998), pp. 563-6.
Thus, a vegan diet lowers IGF-1 by 9%, a seemingly minor amount, yet an 8% difference is all that is seen between healthy and cancer-ridden individuals. IGF-1 is apparently a powerful hormone that only needs a slight elevation above normal to cause damage.
---Among women younger than 50, having high IGF-1 levels raises breast cancer risk by seven times Lancet 351(1998), pp.1393-96.
---The 1,25 form of vitamin D in the body is lowered by diets rich in animal protein and/or too high in calcium. When blood levels of 1,25 vitamin D are depressed, IGF-1 becomes more active. Together these factors increase the birth of new cells while simultaneously inhibiting the removal of old cells, both favoring the development of cancer. This results in 9.5 times increased risk of advanced stage prostate cancer. Journal of National Cancer Insitute 94 (2002), pp. 1099-1109.
---The figures for the chances of women in China dying from breast cancer are
one in ten thousand, as opposed to close to one in thirty-three for the U.S.
The New Optimum Nutrition Bible, Patrick Holford. Berkeley: Crossing Press, 2004. P. 64.
Ovarian Cancer, which is responsible for over 40,000 deaths in the United States each year, is also strongly linked to the consumption of cow’s milk:
A study of 60,000 women found that drinking more than two glasses of milk a day upped the risk of the most serious and most common form of ovarian cancer. Those women who drank two or more glasses a day were at double the risk of those who did not consume it at all, or only in small amounts. American Journal of Clinical Nutrition, (Vol. 80, No. 5, pp. 1353-1357, November 2004)
… and DAIRY IS NOT EVEN NECESSARY FOR STRONG BONES:
---The Nurses’ Health Study (with over 120,000 subjects) found that the consumption of milk does not protect against bone fractures. Those who drank 3 or more servings of milk a day actually had a slightly higher rate of fractures than women who drank little or no milk. American Journal of Public Health 87 (1997). Pp.992-997.
Nutrient “Worries” About Shifting to a Plant-based Diet
Protein, Iron, and Calcium are three nutrients that people associate with animal products, and thus there is a worry that a plant-based diet will be deficient in one or more of them. Whole plant foods generally have adequate amounts of all three of these:
Could a diet containing little or no meat or dairy products put someone at risk of protein deficiency? Not likely, since the protein content in the typical American diet is well above what is required … actually about twice as high as is recommended according to the RDA’s. Too much protein, especially of animal origin, can contribute to loss of calcium from bone, and can overwork the kidneys. The U.S. recommended intake of protein daily is 44 grams for adult women and 56 grams for adult men. These amounts are easily met by consuming plant-based according to the food pyramid guide:
Minerals – Calcium and Iron in Animal versus Plant Foods
Calcium and Iron, considered the two most problematic minerals for Americans, are easily gotten adequately on a plant-based diet. Meat is a very poor source of calcium, and dairy products are poor sources of iron. Trying to achieve a balance usually results in overeating both categories of food. Whole plant foods, in contrast, usually have an appropriate amount of both minerals.
Thus, for considerably less calories than either milk or meat, green vegetables can provide nearly as much or more of these minerals, and in a much more balanced way.