Health101.org
presents
New
Prostate Cancer Studies Implicating Dairy Products
Journal: Cancer
Epidemiology Biomarkers & Prevention
Date: April, 2008
Number of subjects: 43,435 Japanese men ages 45 to 74 years
Study Duration: 90 months
Scientist's Conclusion: "...our results suggest that the intake
of dairy products may be associated with an increased risk of prostate
cancer."
Journal: British
Journal of Cancer
Date: April 1, 2008
Number of subjects: 142,251 European men
Study Duration: 103 months
Scientist's Conclusion: "A 35-gram per day increase in consumption
of dairy protein was associated with an increase in the risk of
prostate cancer of 32%. Calcium from dairy products was also positively
associated with risk, but not calcium from other foods. The results
support the hypothesis that a high intake of protein and calcium
from dairy products may increase the risk for prostate cancer."
Also of note regarding prostate cancer...
IGF-I is identical in human and cow. If you believe
that breast feeding works to protect lactoferrins and immunoglobulins
from digestion (and benefit the nursing infant), you must also recognize
that milk is a hormonal delivery system. By drinking cow's milk,
one delivers IGF-I in a bioactive form to the body's cells. When
IGF-I from cow's milk alights upon an existing cancer, it's like
pouring gasoline on a fire. Scientists have found that the IGF-I
system is widely involved in human carcinogenesis. A significant
association between high circulating IGF-I concentrations and an
increased risk of lung, colon, prostate and pre-menopausal breast
cancer has recently been reported.
"A strong positive association was observed
between IGF-I levels and prostate cancer risk." -- Science,
vol. 279. January 23, 1998
"For prostate cancer, epidemiologic studies
consistently show a positive association with high consumption of
milk, dairy products, and meats." -- Giovannucci E., Adv Exp
Med Biol 1999;472:29-42
"Higher intake of meat and dairy products has
been associated with greater risk of prostate cancer..." --
Willett WC, Salud Publica Mex 1997, Jul-Aug;39(4):298-309
"Positive correlations between foods and cancer
mortality rates were particularly strong in the case of meats and
milk for breast cancer, milk for prostate and ovarian cancer, and
meats for colon cancer." -- Rose DP,
Cancer 1986 Dec 1;58(11):2363-71
"Diet appears to be a major determinant in
the incidence of prostate cancer. In a case-control study conducted
in Athens, Greece, we found that dairy products, butter and seed
oils were positively associated with risk of prostate cancer."
-- Bosetti C, Eur J Cancer Prev 2000, Apr;9(2):119-23
"Diets high in dairy products and meats are
related to higher risk of prostate cancer incidence or mortality
in most ecologic, case-control, and prospective studies." --
Giovannucci E., Cancer Causes Control 1998,
Dec;9(6):567-82
"Suggestive positive associations were also
seen between fatal prostate cancer and the consumption of milk,
cheese, eggs, and meat." -- Snowdon DA,
Am J Epidemiol 1984, Aug;120(2):244-50
"The strongest and most consistent effects
are positive associations with animal products such as red meats,
eggs and dairy foods, and possibly by implication, fat." --
Giles G, Ireland P., Int J Cancer 1997; Suppl
10:13-7
"Among major food groups, milk and dairy products
as well as added lipids were positively associated with risk for
prostate cancer." -- Tzonou A, Int J
Cancer 1999, Mar 1;80(5):704-8
"High consumption of dairy products was associated
with a 50 percent increased risk of prostate cancer." -- Chan
JM, Cancer Causes Control 1998 Dec;9(6):559-66
"Positive trends in risk were found for consumption
of cured meat and milk products." -- Schuurman
AG, Br J Cancer 1999, Jun;80(7):1107-13
Diet
and Prostate Cancer
Scientific evidence clearly shows that
diet has an important influence on prostate cancer risk. Frequent
consumption of meat and dairy products is linked to increased risk,
due, at least in part, to the amount and type of fat they contain.
Animal products also lack the protective nutrients found in vegetables
and fruits.1-3 The disease is rarer among populations consuming
more rice, soybean products, and green or yellow vegetables, and
among vegetarians.4-8 Seventh-day Adventist men, about half of whom
are vegetarians, have only one-third the prostate cancer risk of
other men, and data suggest that the earlier a vegetarian diet is
adopted, the lower the risk.7,8
Dietary factors may influence not only prostate
cancer incidence, but also how quickly it changes from a small growth
causing no clinical problems to an advancing, spreading tumor. The
prevalence of latent cancers (small growths causing no symptoms)
varies somewhat from one country to another, the lowest rates being
in Singapore (13 percent) and Hong Kong (15 percent), and the highest
in Sweden (31 percent).9 The prevalence of advancing cancer, however,
varies much more widely. While a man in Sweden is twice as likely
as a man in Hong Kong to have latent cancerous cells in his prostate,
he is more than eight times more likely to die of prostate cancer.9
Such studies suggest that environmental factors, particularly diet,
may play an important role in the progression of the disease. Plant-based
diets are not only rich in protective nutrients, especially carotenoids
such as lycopene, the natural red color in tomatoes. They are also
very low in fat. Reduced fat intake helps avert testosterone excesses.
Men consuming high-fat diets typically have elevated levels of testosterone
in their blood.10-13 This elevation does not confer any health benefits
(it does not make them more "manly"). Rather, it can overstimulate
the cells of the prostate, increasing cancer risk.
IGF-I and Prostate Cancer
An additional cancer risk relates to a protein in
the bloodstream called insulin-like growth factor-I (IGF-I). Although
a certain amount of IGF-I in the blood is normal, high levels are
linked to increased cancer risk.14-17 IGF-I plays a role in cell
growth among other functions, and test-tube experiments show that
IGF-I encourages cancer cell growth.18,19
Diet has a strong influence on IGF-I. In general,
excess intake of calories or proteins increases the amount of IGF-I
in the blood, and the inclusion of dairy products in the diet merits
particular attention. According to a review published by the World
Cancer Research Fund and the American Institute for Cancer Research,
at least 11 human population studies have linked dairy product consumption
and prostate cancer.20 People increasing the amount of dairy products
in their diets are typically found to have higher levels of IGF-I
in their blood. Following a study of 12-year-old girls in Sheffield,
England, which found that increasing daily milk consumption increased
serum IGF-I concentration, a study of adult men and women showed
that adding three daily eight-ounce servings of nonfat or 1 percent
milk for 12 weeks was associated with a 10 percent increase in serum
IGF-I concentration.21,22 Conversely, plant-based diets may reduce
serum IGF-I levels.23
The most important message is that while consumption
of meat and dairy products appears to increase cancer risk, diets
rich in vegetables and fruits cut risk, giving men more control
over their health than they might otherwise have had.
References
1. Kolonel LN. Nutrition and prostate cancer. Cancer Causes and
Control 1996;7:83-94.
2. Giovannucci E, Rimm EB, Colditz GA, et al. A prospective study
of dietary fat and risk of prostate cancer. J Natl Cancer Inst 1993;85:1571-9.
3. Whittemore AS, Kolonel LN, Wu AH, et al. Prostate cancer in relation
to diet, physical activity, and body size in blacks, white, and
Asians in the United States and Canada. J Natl Cancer 1995;87:652-61.
4. Armstrong B, Doll R. Environmental factors and cancer incidence
and mortality in different countries, with special reference to
dietary practices. Int J Cancer 1975;15:617-31.
5. Hirayama T. Epidemiology of prostate cancer with special reference
to the role of diet. Natl Cancer Inst Monogr 1979;53:149-54.
6. National Research Council. Diet, Nutrition, and Cancer. Washington,
D.C.: National Academy Press, 1982.
7. Phillips RL. Role of life-style and dietary habits in risk of
cancer among Seventh-day Adventists. Cancer Research 1975;35:3513-22.
8. Mills P, Beeson WL, Phillips RL, Fraser GE. Cohort study of diet,
lifestyle, and prostate cancer in Adventist men. Cancer 1989;64:598-604.
9. Breslow N, Chan CW, Dhom G, et al. Latent carcinoma of prostate
at autopsy in seven areas. Int J Cancer 1977;20:680-8.
10. Howie BJ, Shultz TD. Dietary and hormonal interrelationships
among vegetarian Seventh-day Adventists and nonvegetarian men. Am
J Clin Nutr 1985;42:127-34.
11. Hamalainen EK, Adlercreutz H, Puska P, Pietinen P. Decrease
of serum total and free testosterone during a low-fat high-fibre
diet. J Steroid Biochem 1983;18:369-70.
12. Hill PB, Wynder EL. Effect of a vegetarian diet and dexamethasone
on plasma prolactin, testosterone and dehydroepiandrosterone in
men and women. Cancer Lett 1979;7:273-82.
13. Liang T, Liao S. Inhibition of steroid 5a-reductase by specific
aliphatic unsaturated fatty acids. Biochem J 1992;285:557-62.
14. Cohen P. Serum insulin-like growth factor-I levels and prostate
cancer risk-interpreting the evidence. J Natl Cancer Inst 1998;90:876-9.
15. Mantzoros CS, Tzonou A, Signorello LB, Stampfer M, Trichopoulos
D, Adami HO. Insulin-like growth factor I in relation to prostate
cancer and benign prostatic hyperplasia. Br J Cancer 1997;76:1115-8.
16. Chan JM, Stampfer MJ, Giovannucci E, et al. Plasma insulin-like
growth factor-I and prostate cancer risk: a prospective study. Science
1998;279:563-6.
17. Wolk A, Mantzoros CS, Andersson SO, et al. Insulin-like growth
factor I and prostate cancer risk: a population-based, case control
study. J Natl Cancer Inst 1998;90:911-5.
18. Iwamura M, Sluss PM, Casamento JB, Cockett ATK. Insulin-like
growth factor I: action and receptor characterization in human prostate
cancer cell lines. Prostate 1993;22:243-52.
19. Culig Z, Hobisch A, Cronauer MV, et al. Androgen receptor activation
in prostatic tumor cell lines by insulin-like growth factor-I, keratinocyte
growth factor, and epidermal growth factor. Eur Urol 1995;27(suppl
2):45-7.
20. World Cancer Research Fund/American Institute for Cancer Research.
Food, Nutrition, and the Prevention of Cancer: A Global Perspective.
American Institute for Cancer Research. Washington, D.C., 1997,
p. 461.
21. Cadogan J, Eastell R, Jones N, Barker ME. Milk intake and bone
mineral acquisition in adolescent girls: randomised, controlled
intervention trial. BMJ1997;315:1255-60.
22. Heaney RP, McCarron DA, Dawson-Hughes B, et al. Dietary changes
favorably affect bone remodeling in older adults. J Am Dietetic
Asso 1999;99:1228-33.
23. Kontessis PS, Trevisan R, Bossinakou I, et al. Renal, metabolic,
and hormonal responses to proteins of different origin in normotensive,
nonproteinuric type I diabetic patients. Diabetes Care 1995;18:1233-40.
See also "Death
by Doctoring - Cancer: The Good, The Bad and the Ugly"
and "Carcinogen
Found in French Fries, Bread, Biscuits, and Some Interesting Information
about the American Cancer Society"
and "Reasons
Why Women Should Not Get a Mammogram"
and "Cell
Phones and Cancer"
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