What is oxidative stress?

Oxidative stress occurs when highly charged, destructive molecules called free radicals go on a mission to damage and destroy healthy brain cells. This chain reaction is called oxidation, and it is the same chemical reaction that causes apples to brown and iron to rust. While this sounds threatening, most of us produce enough anti-oxidants to quench the free radicals and protect our cells from the stress of oxidation.

Simply put, when large numbers of brain cells become oxidized, communication between brain cells suffers and may eventually be lost. Forgetting names, having difficulty finding words and repeatedly misplacing things are often referred to as "senior moments." Each time you experience a "senior moment", you may be experiencing the damage of oxidative stress.

When there are enough antioxidants, either generated by the body or consumed through diet, the damage of oxidative stress is minimized. For example, in our brains oxidative stress occurs primarily in the space between brain cells sending a message and brain cells receiving a message. The function of sending and receiving messages requires large amounts of energy. Free radicals are formed as a by-product of using energy. The automobile provides a good example of the process of forming free radicals.

Just as an automobile consumes fuel, produces energy and emits pollution, your body cells consume food and oxygen, produce energy and leave behind free radicals. Each cell has its own silent defense network against free radicals. This silent network is the antioxidant defense system.

What to Remember:

  • Antioxidants are important. As the body ages, fewer antioxidants are available.
  • The brain may be vulnerable to free radical damage leading to early memory loss when there are insufficient antioxidants.
  1. Liu R, Choi J. Age-associated decline in gamma glutamylcysteine synthetase gene expression in rats. Free Rad Biol Med. 2000;28:566-574.
  2. Keller JN, et al. Evidence of increased oxidative damage in subjects with mild cognitive impairment. Neurology. 2005;64:1152-1156