膳食、营养与癌症Diet,nutrition,and cancer

rs to further growth and spreading throughout the tissue of origin. ?Metastasis indicates spreading of the cancer to ans.?膳食、营养因素与癌症?致癌物参与癌症发生的第一阶段?膳食、营养因素对癌症发生的决定性影响在促进和进展阶段Р常用研究方法?营养流行病学(Nutritional Epidemiology)?1.描述性研究(Descriptive Study)?相关性研究(correlational study)又称生态学研究(ecological study) ?compare food-disease relationships between large groups(e.g.,countries).Р2.分析性研究(analytic study)?病例对照研究(Case control Study)?compare specific factors between groups of affected and non-affected individuals.?3.实验性研究(Experimental Study)?干预试验 intervention pare es between groups adhering to a specific intervention (as in placebo-controlled drug trials).Р营养素与癌症的关系?总能量摄入(total caloric intake)?动物实验表明,限制能量摄入可以抑制肿瘤形成、延长肿瘤潜伏期、降低肿瘤发病率。?结果解释:供能营养素(蛋白质、碳水化物和脂肪)构成比改变的结果?能量摄入改变的结果??人群流行病学调查:基于癌症的发病率和体重或肥胖的关系,也是间接证据。