Der Extrakt aus dem Prostatakrebs-Forum von KISP und BPS

Ernährung, Nahrungsergänzungen – Zucker

Rudolf verwies am 9.4.2006 auf das Kapitel "Sugar" in dem Buch "Cancer - Nutrition and Survival" von Steve Hickey/Hilary Roberts und fuhr fort:
ich plane gerade für mich ein Experiment mit Vitamin C und Alpha-Liponsäure, bei dem es auch sehr wichtig sein wird, strengste Kohlenhydratkontrolle vorzunehmen, ich werde mir ständig meinen Blutzuckerspiegel kontrollieren. Bei dem Transport in die Zelle hinein sind Glukose und Vitamin C Konkurrenten, sie benutzen dieselben Transportwege: Wenn man will, dass mehr VitC reinkommt, muss man darauf achten, dass wenig Glukose angeliefert wird.
Sugar
Pure, white and deadly” John Yudkin
In well-designed scientific studies, a “sugar pill” is a placebo or dummy, which is given to control subjects in a double-blind trial. Early scientists presumably assumed that sugar was safe and would have minimal effects on the body, making it ideal for comparison with the actions of a drug or treatment.
However, sugar has profound effects: as far as the body is concerned, it contains pure calories. Much of the energy intake of a modern diet is in the form of sugars and starches, which supply nutrient-free energy. High sugar consumption leads to weight gain, particularly when combined with low exercise levels.
Diets high in sugar and carbohydrates lead to poor health.725 A recent self-reported comparison of health and nutrition in 37,053 British people indicates the relationship of sugar to health.726 People who consumed large amounts of sugar-based snacks were about five times more likely to report poor health. Other dietary intakes associated with sugar intake, such as wheat, dairy, refined foods, tea and coffee, were also linked with reduced health. Additional foods related to feelings of illness were red meat and salt. Foods associated with good health had a relatively high ratio of effective antioxidants to carbohydrate; these include fresh fruit, vegetables, salad, seeds, nuts and oily fish.
Overeating is a major risk factor for cancer.725 Obese people are more likely to develop tumours, whereas people who eat less are more resistant. The problem of obesity is rising throughout the western world. The average American is now overweight,727 and two percent or more are severely obese.728 Lack of exercise and poor diet are leading causes of premature death.729 14% of cancer deaths in men and 20% of those in women are related to obesity.730 This includes deaths from cancer of the breast, cervix, colon, oesophagus, gallbladder, kidney, liver, ovary, pancreas, prostate, stomach (male), and uterus.
The appeal of sugar is not limited to humans; it has a broad biological basis. Sugars provide easily assimilated energy for many organisms. As a result, the exchange of sugar is involved in many relationships between organisms.731 For example, the sweet nectar of flowering plants is used to attract insects for pollination. Some plants, such as a species of eucalyptus, excrete large amounts of sugars to attract ants, which provide protection against herbivores. Ants themselves farm caterpillars that excrete sugar. Keeping the caterpillars requires more energy than they excrete in the form of sugars, which indicates the importance of the sugar supply. In some cases, such as with the caterpillar Maculinea arion, the farmed animal will even eat ants.732
The relationship between cancer and its host also depends on the provision of sugars and other essential nutrients, to fuel abnormal growth. This chapter looks at the relationship between sugar and cancer. We will consider prevention of cancer separately from treatment. This is because a diet to help people avoid cancer may differ from a diet that is optimal for a patient with advanced disease. As we consider the role of glucose, it will become apparent that it is intimately related to the actions of vitamin C in the cell. This interaction provides a means for preventing tumour growth and selectively killing cancer cells.
Restricting calories
Those who wish to avoid cancer or to live longer, if they already have the disease, are often advised to cut down on sugar.725,733,749 Glucose deprivation generates oxidative stress within tumours, because of a possible defect in the metabolism of cancer cells.734 One anticancer diet is called Calorie Restriction with Optimal Nutrition (CRON). This consists of eating 70–80% of the calories required to maintain body weight, while getting an optimal level of vitamins and other nutrients. The core restriction is the total energy consumed.
Research has shown that a reduced calorie diet can extend average lifespan in many species, while also reducing the chronic disease load.735 In mice, energy restriction reduces the number of spontaneous tumours.736 Such deprivation inhibits the growth of mammary cancer, suppresses the growth of implanted tumours and increases survival rates.737,738 In Sweden, researchers found that women who had been treated for anorexia nervosa before they were 40 had a 53% lower incidence of breast cancer.739 Although this result is consistent with a large effect of calorie restriction, it is worth noting that these women’s intake of specific vitamins and nutrients was also reduced.
Glucose metabolism
Sugar is the ultimate junk food; it is high in energy but contains no other nutrient value. Sugars and refined flour products make up a large portion of the western diet. Indeed, high carbohydrate diets seem to dominate official recommendations for healthy eating.
One approach to estimating the effect of these foods on the body is the glycaemic index (GI). The glycaemic index is a measure of the metabolic effects of dietary carbohydrates.740,741 The GI measures how a particular food increases blood sugar levels in the body. The higher the GI value, the greater are the body’s glucose and insulin responses to the food in question. Since the body’s response varies with the amount of food, this measure can be misleading. For this reason, a modification called the glycaemic load (GL) has been developed,740 to take into account the amount of food consumed.
For many people, this is a rather unworkable form of dietary advice. To illustrate the problem, we refer the reader to the publication of an international table of the glycaemic index and load of foods. In 2002, the table contained 750 entries.742 Such a table is huge: even a simple meal could require a substantial amount of arithmetic, not to mention guesswork as to the effects of combining different foods. In the longer term, following such a diet may be impractical for the majority of people. However, the approach may be productive in helping to construct general dietary advice guidelines, or for studying the health impacts of manufactured food.
Several projects have investigated the association between glycaemic load and cancer. Controlled studies have shown that a high glycaemic load carries an increased risk of cancer in the higher gut,743,744 uterus,745 ovary,746 and colon.747 Studies of glycaemic index and glycaemic load provide valuable research tools, as high levels of glucose in the blood promote cancer.748,749,820 Indicators of diabetes, such as increased blood glucose, are associated with higher risk of colon cancer.750 Diabetes is associated with increased risk of cancer of the bowel,751,752,753,754,755,756 uterus,757 and pancreas.754,758 Furthermore, diabetes may be an independent predictor of mortality from cancer of the colon, pancreas, liver, bladder and female breast.754
Healthy people can benefit from learning the concept of glycaemic load and its relationship to different types of food. Prospective studies have shown an increased risk of cancer with high glycaemic load.759,760,761 Other studies suggest this risk is specific to sedentary, overweight subjects.762,763,764,765 As is often the case with such studies, others found no increase in risk, providing contradictory evidence.766,767,768,769
Despite these conflicting findings, people wanting to maintain good health would be wise to limit their intake of foods with a high glycaemic index. To a first approximation, the result of reducing the glycaemic load is similar to a low carbohydrate diet.
725 Ely J.T.A. (2003) Inadequate levels of essential nutrients in developed nations as a risk factor for disease: a review, Rev Environ Health, 18(2), 111-29.
726 MyNutrition.co.uk (2004) ONUK Survey – 37,053 respondents.
727 Vastag B. (2004) Obesity is now on everyone's plate, JAMA, 291, 1186-1188.
728 Sturm R. (2000) Increases in clinically severe obesity in the United States, 1986–2000, Arch Intern Med, 163, 2146-2148.
729 Mokdad A.H. Marks J.S. Stroup D.F. Gerberding J.L. (2004) Actual causes of death in the United States, 2000, JAMA, 291, 1238-1245.
730 Calle E.E. Rodriguez C. Walker-Thurmond K. Thun M.J. (2003) Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults, N Engl J Med, 348, 1625-1638.
731 Wackers F. (2002) It pays to be sweet, Biologist, 49(4), 165-169.
732 Holldober B. Wilson E.O. (1990) The Ants, Springer, New York.
733 Yudkin J. (1972) Sweet and Dangerous, Bantam Books, New York.
734 Spitz D.R. Sim J.E. Ridnour L.A. Galoforo S.S. Lee Y.J. (2000) Glucose deprivation-induced oxidative stress in human tumor cells. A fundamental defect in metabolism? Ann N Y Acad Sci, 899, 349-362.
735 Hursting S.D. Lavigne J.A. Berrigan D. Perkins S.N. Barrett J.C. (2003) Calorie restriction, aging, and cancer prevention: mechanisms of action and applicability to humans, Annu Rev Med, 54, 131-152. 280
736 Dirx M.J. Zeegers M.P. Dagnelie P.C. van den Bogaard T. van den Brandt P.A. (2003) Energy restriction and the risk of spontaneous mammary tumors in mice: a meta-analysis, Int J Cancer, 106, 766-770.
737 Harvell D.M. Strecker T.E. Xie B. Pennington K.L. McComb R.D. Shull J.D. (2002) Dietary energy restriction inhibits estrogen-induced mammary, but not pituitary, tumorigenesis in the ACI rat, Carcinogenesis, 23, 161-169.
738 Matsuzaki J. Yamaji R. Kiyomiya K. Kurebe M. Inui H. Nakano Y. (2000) Implanted tumor growth is suppressed and survival is prolonged in sixty percent of food-restricted mice, J Nutr, 130, 111-115.
739 Michels K.B. Ekbom A. (2004) Caloric restriction and incidence of breast cancer, JAMA, 291, 1226-1230.
740 Brand-Miller J. Wolever T.M.S. Foster-Powell K. Colagiuri S. (2002) The New Glucose Revolution: The Authoritative Guide to the Glycemic Index--the Dietary Solution for Lifelong Health, Marlowe & Co, New York.
741 Brand-Miller J. Foster-Powell K. Holt S. Burani J. (2003) The New Glucose Revolution Complete Guide to Glycemic Index Values, Marlowe & Co, New York.
742 Foster-Powell K. Holt S.H. Brand-Miller J.C. (2002) International table of glycemic index and glycemic load values, Am J Clin Nutr, 76, 5-56.
743 Augustin L.S. Gallus S. Negri E. La Vecchia C. (2004) Glycemic index, glycemic load and risk of gastric cancer, Ann Oncol, 15, 581-584.
744 Augustin L.S. Gallus S. Franceschi S. Negri E. Jenkins D.J. Kendall C.W. Dal Maso L. Talamini R. La Vecchia C. (2003) Glycemic index and load and risk of upper aero-digestive tract neoplasms (Italy), Cancer Causes Control, 14, 657-662.
745 Augustin L.S. Gallus S. Bosetti C. Levi F. Negri E. Franceschi S. Dal Maso L. Jenkins D.J. Kendall C.W. La Vecchia C. (2003) Glycemic index and glycemic load in endometrial cancer, Int J Cancer, 105, 404-407.
746 Augustin L.S. Polesel J. Bosetti C. Kendall C.W. La Vecchia C. Parpinel M. Conti E. Montella M. Franceschi S. Jenkins D.J. Dal Maso L. (2003) Dietary glycemic index, glycemic load and ovarian cancer risk: a case-control study in Italy, Ann Oncol, 14, 78-84.
747 Franceschi S. Dal Maso L. Augustin L. Negri E. Parpinel M. Boyle P. Jenkins D.J. La Vecchia C. (2001) Dietary glycemic load and colorectal cancer risk, Ann Oncol, 12, 173-178.
748 Carroll K.K. (1977) Dietary factors in hormone-dependent cancers, Curr Concepts Nutr, 6, 25–40.
749 Hems G. (1978) The contributions of diet and childbearing to breast cancer rates, Br J Cancer, 37, 974–982.
750 Schoen R.E. Tangen C.M. Kuller L.H. Burke G.L. Cushman M. Tracy R.P. Dobs A. Savage P.J. (1999) Increased blood glucose and insulin, body size, and incident colorectal cancer, J Natl Cancer Inst, 91, 1147-1154.
751 McKeown-Eyssen G. (1994) Epidemiology of colorectal cancer revisited: are serum triglycerides and/or plasma glucose associated with risk? Cancer Epidemiology Biomarkers & Prevention, 3(8), 687-695.
752 Hu F.B. Manson J.E. Liu S. Hunter D. Colditz G.A. Michels K.B. Speizer F.E. Giovannucci E. (1999) Prospective study of adult onset diabetes mellitus (type 2) and risk of colorectal cancer in women, J Natl Cancer Inst, 91, 542-547.
753 Colangelo L.A. Gapstur S.M. Gann P.H. Dyer A.R. Liu K. (2002) Colorectal cancer mortality and factors related to the insulin resistance syndrome, Cancer Epidemiol Biomarkers Prev, 11, 385-391.
754 Coughlin S.S. Calle E.E. Teras L.R. Petrelli J. Thun M.J. (2004) Diabetes mellitus as a predictor of cancer mortality in a large cohort of US adults, Am J Epidemiol, 159, 1160-1167.
755 La Vecchia C. Negri E. Decarli A. Franceschi S. (1997) Diabetes mellitus and colorectal cancer risk, Cancer Epidemiol Biomarkers Prev, 6, 1007-1010.
756 Sandhu M.S. Luben R. Khaw K.T. (2001) Self reported non-insulin dependent diabetes, family history, and risk of prevalent colorectal cancer: population based, cross sectional study, J Epidemiol Community Health, 55, 804-805.
757 Anderson K.E. Anderson E. Mink P.J. Hong C.P. Kushi L.H. Sellers T.A. Lazovich D. Folsom A.R. (2001) Diabetes and endometrial cancer in the Iowa women's health study, Cancer Epidemiol Biomarkers Prev, 10, 611-616.
758 Calle E.E. Murphy T.K. Rodriguez C. Thun M.J. Heath C.W. Jr (1998) Diabetes mellitus and pancreatic cancer mortality in a prospective cohort of United States adults, Cancer Causes Control, 9, 403-410.
759 Bostick R.M. Potter J.D. Kushi L.H. Sellers T.A. Steinmetz K.A. McKenzie D.R. Gapstur S.M. Folsom A.R. (1994) Sugar, meat, and fat intake, and non-dietary risk factors for colon cancer incidence in Iowa women (United States), Cancer Causes Control, 5, 38-52.
760 Frazier A.L. Li L. Cho E. Willett W.C. Colditz G.A. (2004) Adolescent diet and risk of breast cancer, Cancer Causes Control, 15, 73-82.
761 Higginbotham S. Zhang Z.F. Lee I.M. Cook N.R. Giovannucci E. Buring J.E. Liu S. (2004) Dietary glycemic load and risk of colorectal cancer in the Women's Health Study, J Natl Cancer Inst, 96, 229-233. 281
762 Cho E. Spiegelman D. Hunter D.J. Chen W.Y. Colditz G.A. Willett W.C. (2003) Premenopausal dietary carbohydrate, glycemic index, glycemic load, and fiber in relation to risk of breast cancer, Cancer Epidemiol Biomarkers Prev, 12, 1153-1158.
763 Folsom A.R. Demissie Z. Harnack L. (2003) Glycemic index, glycemic load, and incidence of endometrial cancer: the Iowa women's health study, Nutr Cancer, 46, 119-124.
764 Higginbotham S. Zhang Z.F. Lee I.M. Cook N.R. Buring J.E. Liu S. (2004) Dietary glycemic load and breast cancer risk in the Women's Health Study, Cancer Epidemiol Biomarkers Prev, 13, 65-70.
765 Michaud D.S. Liu S. Giovannucci E. Willett W.C. Colditz G.A. Fuchs C.S. (2002) Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study, J Natl Cancer Inst, 94, 1293-1300.
766 Holmes M.D. Liu S. Hankinson S.E. Colditz G.A. Hunter D.J. Willett W.C. (2004) Dietary carbohydrates, fiber, and breast cancer risk, Am J Epidemiol, 159, 732-739.
767 Jonas C.R. McCullough M.L. Teras L.R. Walker-Thurmond K.A. Thun M.J. Calle E.E. (2003) Dietary glycemic index, glycemic load, and risk of incident breast cancer in postmenopausal women, Cancer Epidemiol Biomarkers Prev, 12, 573-577.
768 Oh K. Willett W.C. Fuchs C.S. Giovannucci E.L. Glycemic index, glycemic load, and carbohydrate intake in relation to risk of distal colorectal adenoma in women, Cancer Epidemiol Biomarkers Prev, 13, 1192-1198.
769 Terry P.D. Jain M. Miller A.B. Howe G.R. Rohan T.E. (2003) Glycemic load, carbohydrate intake, and risk of colorectal cancer in women: a prospective cohort study, J Natl Cancer Inst, 95, 914-916.
[Eine Übersetzung dieser Studie steht noch aus – Ed]
Bernt verwies am 7.4.2006 auf diese Seite:
http://www.journalonko.de/newsview.php?id=1360
und Rudolf auf den Originaltext der Studie (in englisch):
http://www.jbc.org/cgi/reprint/M511064200v1