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Vitamins, minerals, and other phytonutrients influence many cellular functions that are important in the induction and promotion of cancer, such as cell growth and cell differentiation, antioxidation, DNA synthesis, and cell membrane alterations. They protect against excessive oxidative stress, suppressing free-radical damage when cells are stressed by chemical or radiation-enhanced cell transformation. Protective systems affected by these antioxidants include enzyme induction (e.g., catalase, peroxidase, dismutase), supply of thiols, and interference with free-radical mechanisms in the initiation and promotion stages of malignant transformation.
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The biological mechanisms for cancer inhibition and regression through the use of antioxidant nutrients are gradually becoming understood and appear to act through four types of pathways: |
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1. Tumor inhibition by immune cytokine activation or modulation and through an anti-inflammatory mechanism. |
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2. Stimulation of cancer-suppression genes and down-regulation of oncogenes. |
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3. Inhibition of tumor angiogenesis. |
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4. Stimulation of cellular differentiation and the resultant apoptosis of neoplastic cells. |
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Combinations of antioxidant nutrients and herbs produce a synergistic effect that results in an overall cancer-inhibiting action. Uniquely, these nutrients are also able to selectively act upon cancer cells while allowing healthy cells to function normally. |
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A combination of beta-carotene, vitamin E, and selenium reduced the risk of dying from cancer and other diseases in a National Cancer Institute-sponsored study in Linxian, China. Of the nearly thirty thousand men and women ages forty to sixty-nine who took part in the study, those who took this combination over five years had a 13 percent reduction in cancer death rate and a 9 percent reduction in total death. ''This is a hopeful sign that vitamins and minerals may help prevent the onset of cancer in healthy individuals,'' said William J. Blot of NCI's biostatistics branch and one of the principal investigators of this study.3 |
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Recently, because of a few negative studies that have shown the possibility that certain vitamins may protect a mutated cell from apoptosis (pro- |
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