Irritated Brains

For a healthy brain, put out the inflammatory flame.

Posted Mar 10, 2012

Whatever affects the brain affects the memory.
Whatever affects the memory affects the brain.

If your brain is like mine, it is easily irritated. But brains are irritated in another way you may not have thought about. In my last post I talked about "inflammation" and how body inflammation, from sore joints or sore throat, for example, can trigger inflammation in the brain. Inflammation and "brain rust" are related. First, just what is inflammation? We know from our bodily experiences, that inflammation is indicated by irritation, redness, soreness. What does it do in the brain? Brains can't get sore, but they can get irritated from the release of cytokines and other toxins from the brain's immune cells in response to inflammation. These toxins diminish mental capabilities, especially memory.

Though the brain weighs less than 2% of the body, it "burns" 20% of the oxygen. Oxygen is a very reactive chemical because its outer shell of electrons is not fully occupied, and it reacts readily with chemicals in the brain that can supply electrons to that outer shell of oxygen. Most notably, of course, is the reaction with carbon to carbon dioxide, which occurs in response to the oxidation of the brain's main energy source, glucose. One form of oxygen that is produced in glucose metabolism is the free radical of oxygen. It is especially reactive because it has an unpaired oxygen in its outer electron shell. Free radicals are also produced by pollution, radiation, and cigarette smoke.

Free radical reactions damage tissue, especially structural cell chemicals like DNA, ribosomes, and membrane lipids. In the brain, free radicals destroy nerve terminals and reduce their growth in response to learning experiences. The paradox is you must have energy to live, but the chemistry of generating that energy is killing you as you age. The body does have some "scavenger" chemicals that can help clean up and neutralize free radicals. A good diet also provides free-radical scavengers, such as Vitamins C, E, and beta carotene. These nutrients are found in most fruits and vegetables that have dark colors.

If you think about what was just said, you might think that exercise, which burns a lot of energy, would generate more free radicals. It does, but at the same time the body intrinsic anti-oxidant defense system adapts. Intense exercise in a sedentary person can be damaging if the exercise intensity doesn't build up slowly. Even in a trained athlete, too much exercise might be damaging. I have noticed that many marathon runners look gaunt and sick. They could very well be sick from too much exercise. However, as I have written before, exercise has many advantages that usually compensate for its increased generation of free radicals.

Certainly, if you are older and if you exercise as you should, your body probably needs more anti-oxidants. Vitamin E is helpful, but too much is toxic. Other sources include the plant phenols in blueberries and red wine and grapes, such as resveratrol (now available in highly concentrated pill form). Other powerful anti-oxidants include plant flavonoids found in tea and dark chocolate (sugar-free chocolate is on the market). One flavonoid of special note is luteolin, found in celery, artichokes, and green peppers. Research has revealed it to reduce brain-cell inflammation by suppressing cytokine production as much as 90%.

Because the toxic reactions with free radicals are inflammatory, we could expect that anti-inflammatory drugs, such as aspirin and ibuprofen, would be helpful, but this has not yet been tested on brain inflammation. But remember, these drugs can cause damage to stomach lining and kidneys. The simple and safe approach is to consume plenty of anti-oxidants.


1.     Robertson, J. D. et al. (1991). Increased blood antioxidant systems of runners in response to training load. Clinical Science. 80, 611-618.

2.     Witt, E.H., et al.  (1992). Exercise, Oxidative Damage and Effects of Antioxidant Manipulation (review). Journal of Nutrition 122(3 suppl): 766-773.

3.     Goldfarb, A. H. (1993). Antioxidants: role of supplementation to prevent exercise-induced oxidative stress (review). Medicine and Science in Sports and Exercise. 25(2):232-236.

4.     Jang, S et al. (2008). Luteolin reduces IL-6 production in microglia by inhibiting JNK phosphorylation and the activation of AP-1. PNAS. 105: 7534-7539