The cells in your adult brain — like other body cells — do face two natural enemies: oxidative stress and inflammation. The old news was that after a certain age, say, 30, your brain begins to shrink until it simply shrivels into nothing. But scientists who have actually taken the time to sit down and count brain cells find practically no age-related loss of those hippocampal cells responsible for cognition and memory.
- Oxidative stress is damage done by particles called free radicals that form during chemical reactions occurring in the body. As you grow older, your cells' sensitivity to this kind of injury goes up while your ability to heal afterward goes down.
- Inflammation is your immune system's natural response to injury: swelling, heat, and pain. The American Heart Association regards C-reactive protein (CRP), a protein whose presence increases during inflammation, as a risk factor for heart disease and stroke. A natural increase in the level of tumor necrosis factor alpha and interleukin-6, two inflammatory agents in your brain and spinal cord, appears to play a role in the age-related loss of both cognition and memory.