Hart R W, Turturro A
Division of Biometry and Risk Assessment, National Center for Toxicological Research, Jafferson, Arkansas 72079, USA.
Environ Health Perspect. 1997 Jun;105 Suppl 4(Suppl 4):989-92. doi: 10.1289/ehp.97105s4989.
Dietary restriction (DR) alters a significant environmental factor in carcinogenesis, dietary intake, thus inhibiting both spontaneous and induced tumorigenesis. Potential mechanisms for the inhibition of spontaneous cancer may include the effects of DR to do the following: decrease body weight, which decreases cellular proliferation and increases apoptosis in a number of organs that increase and decrease with body size; decrease body temperature, thereby lowering the amount of endogenous DNA damage temperature generates; decrease oxidative damage, by increasing antioxidant damage defense systems; decrease, generally, cellular proliferation; and protect the fidelity of the genome by decreasing DNA damage, increasing DNA repair, and preventing aberrant gene expression. Potential mechanisms for reducing induced tumor incidence include lowering agent activation, changing agent disposition, decreasing the adducts most associated with agent toxicity, and inhibiting tumor progression through mechanisms similar to those that can effect spontaneous tumorigenesis. As a method to control a major source of environmental cancer, and as the major modulator of the agent induction of this disease, understanding how DR works may significantly contribute to the efforts to explain how diet impacts on development of cancer in the United States, and may suggest methods to reduce the adverse impacts of other environmental agents on the disease.
饮食限制（DR）改变了致癌过程中的一个重要环境因素，即饮食摄入，从而抑制自发和诱导的肿瘤发生。抑制自发癌症的潜在机制可能包括饮食限制产生的以下作用：降低体重，这会减少细胞增殖，并增加一些随体型增大或缩小的器官中的细胞凋亡；降低体温，从而减少内源性DNA损伤温度产生的量；通过增强抗氧化损伤防御系统来减少氧化损伤；总体上减少细胞增殖；以及通过减少DNA损伤、增加DNA修复和防止异常基因表达来保护基因组的保真度。降低诱导肿瘤发生率的潜在机制包括降低致癌物激活、改变致癌物处置、减少与致癌物毒性最相关的加合物，以及通过与影响自发肿瘤发生的机制类似的机制抑制肿瘤进展。作为一种控制环境致癌主要来源的方法，以及作为致癌物诱发这种疾病的主要调节因素，了解饮食限制的作用方式可能会极大地有助于解释饮食如何影响美国癌症的发展，并可能提出减少其他环境因素对该疾病不利影响的方法。
