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Nutrition
for Cancer and Aging page 1 2 3 Slide 14-21. Adipocytes surround the breast duct and proliferate in aging breast tissue so that the postmenopausal breast is largely made up of adipocytes surrounding atrophic breast ducts. Since 75 percent of all breast cancers develop after menopause, it has been proposed that breast fat may have a local paracrine effect on breast ductal cells promoting carcinogenesis. In support of this hypothesis, aromatase levels have been found to be increased in the stromal cells near a breast cancer compared to those at a greater distance from the tumor. Slide 14-22. The Anti-Cancer Food Pharmacy is a depiction of all the classes of substances found in plant-based foods which have an effect on cancer. These include the carotenoids found in yellow, green and orange vegetables, isoflavones found in soy protein, the isothiocyanates in broccoli, organosulfides in garlic and onion, terpenoids found in the skin of citrus fruits. Slide 14-23. The common carotenoids share structural similarities and act as antioxidants. The metabolism of these carotenoids is complex leading to over 600 identified metabolites. Slide 14-24. Only beta-carotene commonly found in carrots and many other vegetables can be converted to vitamin A. The other carotenoids cannot be converted to vitamin A. Slide 14-25. Illustrating the complexity of carotenoid metabolism, lutein is converted into metabolites without vitamin A activity. However, lutein is extremely important in the retina where it has been related to macular degeneration, a common cause of blindness in the elderly. Slide 14-26. The phytoestrogens from soybean protein, genistein and daidzein inhibit tyrosine kinase, and act as selective estrogen response modifiers in cancer cells. The intake of soy protein is higher in countries with lower cancer incidence and the effects of isoflavones suggest that soy may be playing an important role in inhibiting carcinogenesis in these populations. Slide 14-27. In the early 1950’s it was believed that the tumor stole protein from the host causing starvation and death. As shown here, animal tumors grow to a significant fraction of total body weight, and are capable of trapping host nutrients. However, it is very rare for any tumor to increase beyond 1 to 2 kilograms in humans and most metabolic effects are mediated by humoral substances including hormones and cytokines. Slide 14-28. The multiple metabolic effects of tumors on host metabolism including muscle catabolism, liver lipogenesis, fat cell lipolysis, anorexia and reduced food intake are shown here as mediated by a family of cytokines. Therapies for the anorexia and cachexia associated with cancer and AIDS are megestrol acetate, growth hormone and anabolic hormones. Slide 14-29. While lean body mass accurately predicts metabolic rate in normal individuals shown in the dark red, the measured metabolic rates in cancer patients have a much wider distribution with one-third hypometabolic (presumably due to muscle wasting), and one-third hypermetabolic (presumably due to the effects of cytokines and the effects of the tumor on intermediary metabolism). It was once thought that all cancer patients were hypermetabolic due to their failure to gain weight. This is clearly not the case. Slide 14-30. Lean body mass decreases with aging in males as they tend to become less active. There may also be age-related decreases in hormones mediating muscle growth and maintenance. These changes in body composition affect the levels of sex hormones, insulin and growth factors which may affect chronic diseases including diabetes, cardiovascular disease, and common forms of cancer. Efforts at diet and lifestyle change with aging to prevent chronic diseases including cancer need to include interventions to maintain or increase lean body mass.
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Nutrition
101 - Natural
Remedies - Weight
Management - Physician
Education |
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