These vegan health articles are presented to assist you in taking a pro-active part in your own health.
I could have picked any one of the many kinds of cancer which threaten your life for the discussions that follow. One advantage of using prostate cancer for my example is that the male-dominated medical business has been more willing to accept the diet-cancer connection, and the short-comings of early detection and treatment, for this exclusively male-disease, than they have been for the predominantly female disease, breast cancer. Breast cancer is essentially the same disease in women as prostate cancer is in men (those of you interested in breast cancer should read the McDougall Program for Women book). As you read, you can assume that a parallel story can also be told for breast cancer, as well as, to some degree, for colon, kidney, and pancreatic cancer.
Prostate cancer is the leading kind of cancer and the second leading cause of cancer death for men (after lung cancer). The typical American man has a one in ten chance of being diagnosed with this disease, and a 3% chance of dying from it. As many as 30% of men in their 30s and 40s have prostate cancer; and nearly all men who reach the age of 100 show microscopic evidence of this disease.1 I have taken two important steps to protect my own prostate:
First, I eat a diet that supports a healthy prostate and discourages cancer growth (the subject of this newsletter) and;
Second, I avoid prostate screening tests, specifically the PSA (prostate specific antigen) test and the digital rectal exam (DRE) of my prostate (the subject of next month’s newsletter).
Everything Causes Cancer; Nothing Causes Cancer
Because there is a large library of information that appears (after a superficial glance) to be completely contradictory, most people are thoroughly confused about how to protect themselves from cancer. An analogy from a 19th century medical mystery, solved by open-minded and clever detective work, will help me explain to you how to sort through the information and reduce your risk for most common cancers.
The Broad Street Pump
Cholera, an often-fatal infectious disease, spread throughout England beginning in 1831. At that time, this disease was believed to be from "miasma in the atmosphere." Miasma refers to foul or malodorous vapors (air) that cause disease. Four serious epidemics, taking tens of thousands of lives in England, occurred from then until 1854 when an anesthesiologist, John Snow, solved the mystery.
Dr. Snow noticed that the distribution of cases of cholera was largely confined to those people who obtained their water from one particular well, called the Broad Street Pump. He also observed that of the 530 inmates of the Poland Street workhouse, which was around the corner from the Broad Street Pump, only five people had contracted cholera; and that no one from the workhouse drank the pump water, for the building had its own well. Among the 70 workers in a Broad Street brewery, where the men were given an allowance of free beer every day, and consequently never drank water, there were no fatalities. These findings resulted in the identification of the well as the source of cholera and the removal of the handle from the well’s pump – the epidemic of cholera ended.
Almost 30 years passed before it was recognized that the cause of this disease was a bacteria called Vibrio cholerae; however, this did not stop Dr. Snow and the community surrounding the Broad Street Pump from taking action that saved thousands of lives. The important message here is that even without identifying the exact agent causing the disease, they saved themselves by avoiding the well. Dr. Snow’s work marks the beginning of the science of epidemiology.
Here is the analogy: the Western diet is the “Broad Street Pump” – And even though scientists may not agree upon the exact component(s) of the food that is (are) causing and promoting the cancer, all the evidence points to the food. Just as you would not need to know that Vibrio cholerae was the exact killing agent before you stopped drinking from the Broad Street Pump; you do not need to know exactly which one of, or combination of, the food-derived culprits are causing cancer before you avoid the Western diet (the well) and change to a healthy plant-based diet.
The World Picture
The link between diet and prostate cancer is shown in many ways, but the studies of populations of people worldwide are some of the most convincing. Prostate cancer is rare in parts of the world where people eat a low-fat, nearly-vegetarian diet. For example, there is 120 times less incidence of prostate cancer in China compared to men in the United States.2 However, as these populations of Chinese people change to the Western diet, their risk increases proportionally3. This was demonstrated in one recent study in China where they found a man’s chance for developing prostate cancer increased with increasing intake of animal products and dietary fats, both saturated (animal) and unsaturated (vegetable).4 Also, among foreign-born Asians, the risk of prostate cancer increases with years of residence in the United States, as well as with increasing saturated (animal) fat intake.5
Many Facets of the Rich Diet
As you read through the evidence you will see there are many components of the Western diet including fat, animal protein, cholesterol, and chemicals that are believed to initiate and promote cancer. Likewise, there are many healthy components missing from this rich diet, such as powerful antioxidants, phytochemicals, and dietary fiber, which protect us from cancer. People are confused because there are so many different theories concerning the agent(s) causing prostate cancer – yet if you take one giant step back you will see they are all talking about the same diet – the rich Western diet. Let’s look at some of the suspected culprits connecting our diet with cancer, and more specifically, prostate cancer.
The Dairy Connection:
After nearly a century of cow’s milk being marketed as “Nature’s Most Perfect Food,” you may be surprised to learn that dairy products have consistently been associated with an increased risk of prostate cancer. A June 1999 article in the journal Alternative Medicine Reviews reported that the relationship of prostate cancer worldwide was more strongly related to the consumption of nonfat dairy products than to any other food product.6 In one recent study, from the Harvard School of Public Health, high consumption of dairy products was associated with a 50% increase in the risk of prostate cancer.7 Even though the exact mechanism for the relationship remains unknown, one possibility involves vitamin D. This vitamin is known to protect us from prostate cancer. Consuming calcium (as with dairy foods) lowers the circulating levels of this vitamin, eliminating its protective qualities.
Another mechanism linking dairy products and prostate cancer is a very powerful growth-stimulating hormone, known as insulin-like growth factor-1 (IGF-1). This hormone is increased in the body by the consumption of protein, and especially animal protein. However, dairy products are the worst offenders of all the foods we eat for raising this cancer-promoter.8 They can easily increase the levels in our bodies by 10% from consuming amounts of dairy products commonly recommended to keep our bones strong – and this fact comes from studies paid for by the dairy industry.9,10 On the other hand, vegan men have been found to have a 9% lower level of IGF-1 than men who follow a diet with meat and dairy products.11
Dairy products may also influence prostate cancer development and growth by their high content of environmental chemicals, by their saturated fat, and/or by raising testosterone levels.12 But, the exact details are practically unimportant for us to take sensible action and eliminate these foods from our diet.
The Beef Connection:
A high intake of both red meat and dairy products has been associated with a two-fold elevation in risk of metastatic prostate cancer, compared to low intake of both products, but it is not clear whether the high fat content of these foods or some other component is responsible.13,14 Beef fat (tallow) has been shown to be especially prostate cancer-promoting, when compared to other kinds of fat in animal studies.15 Beef may also influence cancer development by increasing IGF-1 levels, its high environmental chemical content, by raising testosterone levels, and/or by the chemicals produced through cooking. But, the exact details are practically unimportant for us to take sensible action and eliminate these foods from our diet.
The Fat Connection:
Some of the earliest scientific research discovered that high-fat diets increase the risk of cancer, including prostate cancer. The mechanisms vary. Fatty foods are high in calories and excess calories promote cancer, possibly because they promote growth of all kinds of tissues, including the growth of cancer cells. Vegetable fats suppress the immune system, thus encouraging cancer growth. High-fat diets are high in chemical contaminants, and they raise hormone levels – like increasing the production of the male hormone, testosterone.
Fats of all kinds, including vegetable fats, including “health-food” olive and flaxseed oil, are easily oxidized into highly reactive molecules which trigger a host of cancer-causing processes, including damaging our DNA.16 Fortunately, these reactions are stopped by antioxidants, such as vitamin E, lycopene (found in red pigmented plants), and selenium, found in plant foods.
Thus, fats of all kinds may also influence cancer development by a variety of mechanisms. But, the exact details are practically unimportant for us to take sensible action and eliminate these foods from our diet.
The Testosterone Connection:
Testosterone is a sex hormone produced by the testicles. The prostate gland requires this hormone to grow and function properly. Men who lose both testicles early in life, and who don't have testosterone replacement, do not get prostate cancer. Men with prostate cancer have higher than average levels of testosterone. Furthermore, stimulation with these male hormones over a period of time causes prostate cancer to grow, like throwing gasoline on a fire; and an important corollary is that lowering hormone stimulation over time will prevent prostate cancer and slow the growth of any cancer that has already developed.17,18 These observations have led to the development of widely-prescribed, anti-testosterone drugs for the prevention and treatment of prostate cancer.
The safest and most effective way to keep male hormones under control is to encourage men to eat a low-fat, high fiber diet.19-22 There are several mechanism by which testosterone is reduced in the body with a healthy diet; for example; plant substances known as isoflavones inhibit the production of testosterone.23 But remember like John Snow and the Broad Street Pump, the exact details of how raised testosterone activity, caused by the rich Western diet, affects cancer growth are practically unimportant for us to take sensible action and eliminate hormone-enhancing foods from our diet.
The Cooking Connection:
Cooking animal muscles, including beef, poultry, and fish at high temperatures by broiling, roasting or frying, causes the production of very potent cancer-causing substances, such as heterocyclic amines. These heat-created chemicals can damage the genetic materials inside the cells (DNA), causing mutations and cancer -- and have been tied to the development of prostate cancer.24,25 Importantly, eating vegetables, notably broccoli, will increase the metabolism of these cancer-causing chemicals and remove them from the body so they are no longer hazardous.26 But, the exact details of how these cooking-derived chemicals promote cancer are practically unimportant for us to take sensible action and eliminate these foods from our diet.
The Chemical Connection:
A number of chemicals found in the environment influence the development of prostate cancer. For example, chemicals, known as organochlorines, mimic the role of hormones binding to hormone receptors in our sex organs, including the prostate, and promote cancer growth. Organochlorines, first produced in the early 1900's, have been made on a large scale since the Second World War, when they were used as poison gases. They include DDT, PCBs, dioxin, Agent Orange and thousands of lesser-known chemical products and byproducts. Each year in North America, 13 million tons of chlorine are produced and used to chlorinate drinking water and are employed in the production of plastics and the bleaching of paper. These environmental substances are also called xenoestrogens and endocrine disrupters.
Over the past 20 years, the documented increase in the disorders of male sexual organs, such as hypospadias (the urethra ends at the base of the penis), cryptorchidism (undescended testis), poor semen quality, testicular cancer and micropenis, has led to the suspicion that environmental chemicals are detrimental to normal male genital development. Increasing rates of prostate cancer may also result in part from these and other man-made chemicals.27
The higher on the food chain, the higher the concentration of these environmental chemicals in the ecosystem. The concentrating process, known as biomagnification, occurs because these chemicals are attracted to fat and stored in body fat. So, when the cattle eat the chemicals on the grass, the chemicals become concentrated in the cattle’s fatty tissues. After we eat the beef fat most of these chemicals are stored in our fat. Estimates are 80% to 90% of the chemicals in our bodies come from eating meat, poultry, fish, and dairy products. Understand that this accumulation is life-long, and therefore, what you do as a child may come to haunt you as an adult with cancer and birth defects for your children. Fortunately, eating a clean diet allows these chemicals to leave the body. Thus, the exact details on which chemicals and how they act are practically unimportant for us to take sensible action and eliminate foods high on the food chain (meats and dairy products) from our diet and replace them with foods low on the food chain (plant foods).
Plant-Food Protection Connection:
Vegetables contain dozens of discovered, and hundreds of to-be-discovered, substances, called phytochemicals, which play a protective role on our tissues with numerous anticancer actions.16 In one important study, the strongest protector from prostate cancer was related to the consumption of tomatoes -- the lycopene in tomatoes acted as an antioxidant, preventing prostate cancer.6
One well studied group of phytochemicals, known as isoflavones, has been found to inhibit the growth of prostate cancer in mice.29 After feeding the mice soy products, examination of the animal’s prostate tissues under a microscope showed reduced cell replication, increased cell death, and a decrease in the number of blood vessels that go to the tumor – all indicating a reduction in already established cancer. The low rate of prostate cancer in Japanese men is often attributed to the large quantities of these natural plant-derived chemicals in their diet of rice, vegetables, and soy products. Obviously, the exact details on how these phytochemicals act to keep our tissues healthy and cancer-free are practically unimportant for us to take sensible action by flooding our cells with this life-giving assistance.
What if you have cancer already? Can diet help?
Because of the limited efficacy of present day treatments for prostate cancer, the medical community has encouraged doctors to look at nontraditional therapies, such as diet. Diet therapy has reached a level of acceptance where the respected Journal of Urology prints, “...dietary fat intake modification may be a promising intervention to prevent prostate cancer progression”31 This statement is based in part on the fact that a study of 384 men diagnosed with prostate cancer found those who consumed the least amount of animal fat had one-third the risk of dying compared to those who ate the highest fat intake.32
The benefits of healthier living for men who already have prostate cancer can be seen in a simple laboratory experiment. Cancer cells placed in a dish, then covered with the serum (blood) of overweight men, grew more slowly after these men had followed a low-fat, high-fiber diet and exercised for only 11 days; compared to incubation of these same cancer cells in serum taken before the intervention.33 Diet and exercise cause changes in the blood and body that inhibit cancer cell growth.
PSA (prostatic specific antigen) is a sugar-protein often elevated in the blood of men with prostate cancer and the level of this hormone reflects the rate of growth of the cancer. A rising level indicates a losing battle. In one study, men with elevated PSA levels, but without cancer, who changed to a low-fat diet, high in soy products, showed the average serum PSA level reduction from 6.9 ng/ml to 5.6 ng/ml after 3 months.34 In another study of men with prostate cancer, the rate of rise of PSA decreased in 8 of 10 men, while 3 had a decrease in absolute PSA level, when following a low-fat, plant-based diet. More evidence that this intervention slows the rate of tumor progression.35
A study of men with prostate cancer found that after an average duration of 34 days on a low-fat diet (20% fat), supplemented with an ounce of flaxseeds daily, there was a decrease in total serum cholesterol, total testosterone, and free androgen index (a measurement of male hormone activity).36 PSA levels decreased slightly, and most importantly, the actual activity of cancer cell growth, as seen under the microscope, decreased in those on the diet. The longer the men with cancer were on the diet, the healthier the growth pattern of the cancer cells appeared. Finally, ongoing research by Dr. Dean Ornish, using a low-fat, vegan diet, has already produced encouraging results for men with prostate cancer.37,38
Logically, it would make about as much sense for cholera victims, after learning the truth, to continue drinking from the polluted Broad Street Pump, as it would to continue feeding cheeseburgers to a person with cancer.
Broad Street Food Pump = the Western Diet
After reading this article, you now are able to step back and look at the evidence from an expansive perspective and see that there is consistency in what once seemed to be disjointed messages. Choosing the right foods is 100% within your control, costs nothing (actually reduces your food bill by 40%), causes painless permanent weight loss, and results in a dramatic reduction in other diseases, like heart disease, obesity, diabetes, and arthritis. Today seems like a good day to make some healthy changes. What do you think?
1) Barry MJ. Should Medicare provide reimbursement for prostate-specific antigen testing for early detection of prostate cancer? Part I: Framing the debate. Urology. 1995 Jul;46(1):2-13.
2) Wang Y. Decreased growth of established human prostate LNCaP tumors in nude mice fed a low-fat diet. J Natl Cancer Inst. 1995 Oct 4;87(19):1456-62.
3) Sung JF. Risk factors for prostate carcinoma in Taiwan: a case-control study in a Chinese population. Cancer. 1999 Aug 1;86(3):484-91.
4) Lee MM. Case-control study of diet and prostate cancer in China. Cancer Causes Control. 1998 Dec;9(6):545-52.
5) Whittemore AS. Prostate cancer in relation to diet, physical activity, and body size in blacks, whites, and Asians in the United States and Canada. J Natl Cancer Inst. 1995 May 3;87(9):652-61.
6) Grant WB. An ecologic study of dietary links to prostate cancer. Altern Med Rev. 1999 Jun;4(3):162-9
7) Chan JM. Dairy products, calcium, phosphorous, vitamin D, and risk of prostate cancer (Sweden) Cancer Causes Control. 1998 Dec;9(6):559-66.
8) Holmes MD. Dietary Correlates of Plasma Insulin-like Growth Factor I and Insulin-like Growth Factor Binding Protein 3 Concentrations. Cancer Epidemiol Biomarkers Prev 2002 Sep;11(9):852-61
9) Heaney RP. Dietary changes favorably affect bone remodeling in older adults. J Am Diet Assoc. 1999 Oct;99(10):1228-33.
10) Cadogan J. Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial. BMJ. 1997 Nov 15;315(7118):1255-60.
11) Allen NE. Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men. Br J Cancer. 2000 Jul;83(1):95-7.
12) Kaaks R. Plasma androgens, IGF-1, body size, and prostate cancer risk: a synthetic review. Prostate Cancer Prostatic Dis. 2000 Nov;3(3):157-172.
13) Michaud DS. A prospective study on intake of animal products and risk of prostate cancer. Cancer Causes Control. 2001 Aug;12(6):557-67.
14) Giovannucci E. A prospective study of dietary fat and risk of prostate cancer. J Natl Cancer Inst. 1993 Oct 6;85(19):1571-9.
15) Mori T. Beef tallow, but not perilla or corn oil, promotion of rat prostate and intestinal carcinogenesis by 3,2'-dimethyl-4-aminobiphenyl. Jpn J Cancer Res. 2001 Oct;92(10):1026-33.
16) Fleshner NE. Diet, androgens, oxidative stress and prostate cancer susceptibility. Cancer Metastasis Rev. 1998-99;17(4):325-30.
17) DePrimo SE. Prevention of prostate cancer. Hematol Oncol Clin North Am. 2001 Jun;15(3):445-57.
18) Brawley OW. Prostate cancer prevention trials in the USA. Eur J Cancer. 2000 Jun;36(10):1312-5.
19) Howie BJ. Dietary and hormonal interrelationships among vegetarian Seventh-Day Adventists and nonvegetarian men. Am J Clin Nutr. 1985 Jul;42(1):127-34.
20) Key TJ. Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores. Br J Nutr. 1990 Jul;64(1):111-9.
21) Habito RC. Postprandial changes in sex hormones after meals of different composition. Metabolism. 2001 May;50(5):505-11.
22) Belanger A. Influence of diet on plasma steroids and sex hormone-binding globulin levels in adult men. J Steroid Biochem. 1989 Jun;32(6):829-33.
23) Krazeisen A. Human 17beta-hydroxysteroid dehydrogenase type 5 is inhibited by dietary flavonoids. Adv Exp Med Biol. 2002;505:151-61.
24) Ferguson LR. Meat consumption, cancer risk and population groups within New Zealand. Mutat Res. 2002 Sep 30;506-507:215-24.
25) Hein DW. Association of prostate cancer with rapid N-acetyltransferase 1 (NAT1*10) in combination with slow N-acetyltransferase 2 acetylator genotypes in a pilot case-control study. Environ Mol Mutagen. 2002;40(3):161-7.
26) Felton JS. Human exposure to heterocyclic amine food mutagens/carcinogens: relevance to breast cancer. Environ Mol Mutagen. 2002;39(2-3):112-8.
27) Skakkebaek NE. Endocrine disrupters and testicular dysgenesis syndrome. Horm Res. 2002;57 Suppl 2:43.
28) Griffiths K. Certain aspects of molecular endocrinology that relate to the influence of dietary factors on the pathogenesis of prostate cancer.
Eur Urol. 1999;35(5-6):443-55.
29) Zhou JR. Soybean phytochemicals inhibit the growth of transplantable human prostate carcinoma and tumor angiogenesis in mice. J Nutr. 1999 Sep;129(9):1628-35.
30) Lee CT. The role of dietary manipulation in biochemical recurrence of prostate cancer after radical prostatectomy. Semin Urol Oncol. 1999 Aug;17(3):154-63.
31) Bairati I. Dietary fat and advanced prostate cancer. J Urol. 1998 Apr;159(4):1271-5.
32) Fradet Y. Dietary fat and prostate cancer progression and survival. Eur Urol. 1999;35(5-6):388-91.
33) Tymchuk CN. Evidence of an inhibitory effect of diet and exercise on prostate cancer cell growth. J Urol. 2001 Sep;166(3):1185-9.
34) Tsutsumi M. A low-fat and high soybean protein diet for patients with elevated serum PSA level: alteration of QOL and serum PSA level after the dietary intervention. Hinyokika Kiyo. 2002 Apr;48(4):207-11.
35) Saxe GA. Can diet in conjunction with stress reduction affect the rate of increase in prostate specific antigen after biochemical recurrence of prostate cancer? J Urol. 2001 Dec;166(6):2202-7.
36) Demark-Wahnefried W. Pilot study of dietary fat restriction and flaxseed supplementation in men with prostate cancer before surgery: exploring the effects on hormonal levels, prostate-specific antigen, and histopathologic features.
Urology. 2001 Jul;58(1):47-52.
37) Ornish DM. Dietary trial in prostate cancer: Early experience and implications for clinical trial design. Urology. 2001 Apr;57(4 Suppl 1):200-1.
38) Personal communication with Dean Ornish.
We began this archive as a means of assisting our visitors in answering many of their health and diet questions, and in encouraging them to take a pro-active part in their own health. We believe the articles and information contained herein are true, but are not presenting them as advice. We, personally, have found that a whole food vegan diet has helped our own health, and simply wish to share with others the things we have found. Each of us must make our own decisions, for it's our own body. If you have a health problem, see your own physician.