Harman D
Department of Medicine, University of Nebraska College of Medicine, Omaha 68198-4635.
Mutat Res. 1992 Sep;275(3-6):257-66. doi: 10.1016/0921-8734(92)90030-s.
Free radical reactions are ubiquitous in living things. Studies on the origin and evolution of life provide a reasonable explanation for the prominent presence of this unruly class of chemical reactions. These reactions have been implicated in aging. This phenomenon is the accumulation of changes responsible for the sequential alterations that accompany advancing age and the associated progressive increases in the chance of disease and death. Aging changes are attributed to the environment and disease, and to an inborn process, the aging process. The latter produces aging changes at an exponentially increasing rate with advancing age. Past improvements in general living conditions have decreased the chances for death so that they are now near limiting values in the developed countries. In these countries the intrinsic aging process is the major cause of disease and death after about age 28. The free radical theory of aging postulates that aging changes are caused by free radical reactions. The data supporting this theory indicate that average life expectancy at birth may be increased by 5 or more years, by nutritious low caloric diets supplemented with one or more free radical reaction inhibitors.
自由基反应在生物界普遍存在。对生命起源和进化的研究为这类难以控制的化学反应的显著存在提供了合理的解释。这些反应与衰老有关。衰老现象是指随着年龄增长而发生的一系列变化的积累，以及随之而来的疾病和死亡几率的逐渐增加。衰老变化归因于环境、疾病以及一种内在过程——衰老过程。后者随着年龄的增长以指数级增长的速度产生衰老变化。过去总体生活条件的改善降低了死亡几率，以至于在发达国家现在已接近极限值。在这些国家，大约28岁之后，内在的衰老过程是疾病和死亡的主要原因。衰老的自由基理论假定衰老变化是由自由基反应引起的。支持这一理论的数据表明，通过补充一种或多种自由基反应抑制剂的营养低热量饮食，出生时的平均预期寿命可能会延长5年或更长时间。
