If a young or middle-aged man, when leaving company, does not recollect where he laid his hat, it is nothing; but if the same inattention is discovered in an old man, people will shrug up their shoulders
and say, “His memory is going.”
— SAMUEL JOHNSON
AGE-RELATED MEMORY LOSS occurs in all mammals, from mice to humans. Research has narrowed down the myriad biological theories of aging into a few that are backed by scientific evidence: genetically programmed cell death, disruption of biological clocks, and free radical toxicity.
Programmed Death of Cells
The theory of programmed cell death states that every cell in the body is genetically programmed to die at a certain point in time, and that this time frame is specific for each type of cell. Many cells in the body regularly die, but other reproducing cells make up the deficit. Erythrocytes, or red blood cells, that carry hemoglobin have an average life span of only 120 days, but stem cells in the bone marrow continually develop into new erythrocytes and enter the bloodstream to make up for this loss. But in cells that do not reproduce and are meant to last a lifetime, especially those in the brain, programmed cell death may play a major role. Just as there are genes that tell each cell to synthesize the right kinds of proteins to maintain life, other genes are programmed to turn off protein synthesis and destroy the cell. Currently, we do not know what triggers these “suicide ’’ genes to come alive as we grow older. If the genes that trigger programmed cell death are successfully blocked, the human life span can be greatly prolonged. But what will society be like if new genetic therapies make people live to the age of 150 or 200 years? If in addition to increased longevity there is a corresponding improvement in quality of life, then the ensuing problems won’t be as overwhelming as we now imagine.
Taken From: The Memory Program How to Prevent Memory Loss
and Enhance Memory Power
