Efficacy of Antioxidant Vitamins and Selenium Supplement in Prostate Cancer Prevention: A Meta-Analysis of Randomized Controlled Trials
The First Hospital of Lanzhou University, 199 Donggang West Road, Chengguan District, Lanzhou, Gansu, China.Nutrition and Cancer (Impact Factor: 2.32). 07/2010; 62(6):719-27. DOI: 10.1080/01635581.2010.494335
Several studies have evaluated the possible association between antioxidants vitamins or selenium supplement and the risk of prostate cancer, but the evidence is still inconsistent. We systematically searched PubMed, EMBASE, the Cochrane Library, Science Citation Index Expanded, Chinese biomedicine literature database, and bibliographies of retrieved articles up to January 2009. We included 9 randomized controlled trials with 165,056 participants; methodological quality of included trials was generally high. Meta-analysis showed that no significant effects of supplementation with beta-carotene (RR 0.97, 95% CI 0.90-1.05) (3 trials), vitamin C (RR 0.98, 95% CI 0.91-1.06) (2 trials), vitamin E (RR 0.96, 95% CI 0.85-1.08) (5 trials), and selenium (RR 0.78, 95% CI 0.41-1.48) (2 trials)versus placebo on prostate cancer incidence. The mortality of prostate cancer did not differ significantly by supplement of beta-carotene (RR 1.19, 95% CI 0.87 -1.65) (1 trial), vitamin C (RR 1.45, 95%CI 0.92-2.29) (1 trial), vitamin E (RR 0.85, 95%CI 0.58-1.24) (2 trials), and selenium (RR 2.98, 95% CI 0.12-73.16) (1 trial). Our findings indicate that antioxidant vitamins and selenium supplement did not reduce the incidence and mortality of prostate cancer, these data provide no support for the use of these supplements for the prevention of prostate cancer.
Article: Vitamin C: Overview and Update[Show abstract] [Hide abstract]
ABSTRACT: Vitamin C functions in enzyme activation, oxidative stress reduction, and immune function. There is considerable evidence that vitamin C protects against respiratory tract infections and reduces risk for cardiovascular disease and some cancers. Current trials are examining the efficacy of intravenous vitamin C as cancer therapy. Many experts believe that the recommended intakes for vitamin C (45 to 90 mg daily) are several orders of magnitude too low to support optimal vitamin C functionality. Also, there is a misperception that vitamin C deficiency disease (scurvy) is largely historical and rarely observed in developed nations. Physical symptoms of scurvy include swelling of the lower extremities, bleeding gums, fatigue, and hemorrhaging, as well as psychological problems, including depression, hysteria, and social introversion. The long-term safety of vitamin C supplementation seems evident as large investigations have noted reduced risk of mortality in vitamin C supplementing populations and in those with elevated plasma vitamin C concentrations.Journal of Evidence-Based Complementary and Alternative Medicine 03/2011; 16(1):49-57. DOI:10.1177/1533210110392951
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ABSTRACT: This study aims to assess various types of nutritional intervention for improving treatment tolerance in patients with malnutrition related to the cancer anorexia-cachexia syndrome. Malnutrition in cancer patients is associated with a poor prognosis, whereas weight loss is an important predictor of mortality. Disease and treatments have a major impact on nutritional status. By improving the latter, we can change the prognosis, quality of life and functional status, facilitating improved tolerance to treatment. Dietary counselling, recommended for patients at risk of malnutrition, should be introduced early in close collaboration with the patient. Administering oral nutritional supplements to malnourished patients has been shown to lead to a reduction in mortality, in complications and in the length of hospital stay. Supplementation with enteral nutrition has demonstrated an increase in appetite, energy intake, nutritional status and, above all, reduced gastrointestinal toxicity from cancer treatments due to a better response to them. Supplementation with home parenteral nutrition in aphagic and terminal patients has shown improved quality of life, energy balance, body composition and prolonged survival. Supplementation with ω3 fatty acids appears to offer benefits that are verifiable at a biochemical, clinical and functional level. Related literature, however, provides conflicting results; therefore further studies will be required to confirm their efficacy. Supplementation with glutamine appears to support the efficacy of chemoradiotherapy treatment while reducing toxicity of the tissues and improving outcomes. Oral supplementation with branched amino acid appears to reduce the length of hospital stay, decrease morbidity and improve the quality of life, without any changes in mortality. Perioperative supplementation with arginine has shown a reduced incidence of complications and a significant increase in long-term survival.Current opinion in oncology 07/2011; 23(4):322-30. DOI:10.1097/CCO.0b013e3283479c66 · 4.47 Impact Factor
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ABSTRACT: Long-period food storage vertical freezers are small cooling capacity appliances usually working with HC. The particular system architecture and the small thermal load allow the use of natural draft wires and tube heat exchangers with large heat transfer areas. Despite of the good performance achieved, high refrigerant charges with respect to the cooling capacity of the system are required, due to the high volumes of the heat exchangers.In this work an experimental analysis of an apparatus with a typical arrangement of the heat exchangers and capillary tube is presented. The system was first designed according to the current standards to reach high performances. Then the working conditions of the system were completely characterized experimentally in the whole range of refrigerant charges compatible with steady operation.Some general conclusions about the systems with this kind of architecture are furnished about the determination of the thermodynamic optimum operating condition and, hence, the determination of the optimum charge.International Journal of Refrigeration 08/2011; 34(5):1305-1314. DOI:10.1016/j.ijrefrig.2010.11.006 · 2.24 Impact Factor
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