The human body is composed of cells, which make up your tissues and body organs. Most of these cells replicate themselves, while some do not divide themselves, such as heart cells and neurons in the brain. Human cells require both energy and oxygen in order to function optimally.

One of the reasons why you age is that your body cells are attacked by free radicals.

Free radicals are a natural byproduct of everyday reactions that produce energy for your body. The energy is produced by reactions between many substances and oxygen in your body.

The free radical theory of aging was first introduced by Dr. Denham Harmon in 1956. According to Dr. Harmon's theory, your body is composed of negatively and positively charged molecules, which form your skin, brain and other body organs. These negatively and positively charged molecules must be balanced or neutral in order to provide a healthy environment for cell renewal and rejuvenation.

Molecules, including oxygen, fatty acids, amino acids, and DNA, are basic components used to build and repair your body cells. These molecules are held together by electrons. Stable molecules have electrons that are paired. When a molecule does not have a pair, it becomes extremely reactive, and begins searching for a pair to make it stable. Basically, it will do just about anything to find a partner, including stealing and damaging other molecules. When a stable molecule loses an electron, it becomes a free radical, which then steals an electron from another stable molecule, causing that molecule to become imbalanced, and so a chain reaction ensues. Disease and degeneration occur when there is imbalance in molecules. Having an electron deficit, due to the imbalance, molecules can be extremely reactive and damaging to body proteins and fats, in particular the DNA.

There are several types of free radicals created by the environment, and oxygen free radicals are the most damaging ones, especially to your DNA and cell membranes.

As you age, your immune system weakens, as evidenced by frequent incidence of infections and influenza. This is because your B- and T-cells in your immune system become inhibited when they are frequently exposed to oxidizing compounds of oxygen free radicals.

The cumulative damage to your DNA as a result of exposure to free radicals is a major cause of many human cancers.

When you are over sixty, you may have a higher risk of cataracts, which is a clouding of the lens in the eye, resulting in blurry vision. Fortunately, vitamins C and E, and carotenoids have strong preventive effects on cataracts.

Another damaging role of oxygen free radicals is their impact on cardiovascular diseases. When your LDL or "bad cholesterol" is attacked by free radicals, it becomes more easily attached to the walls of your arteries, forming plaques that block the flow of blood to your heart. These hazardous conditions are often precursors of heart attacks.

Finally, the neurons in your brain can be damaged by oxygen free radicals. The damage to the neurons may be irreparable because neurons, unlike other body cells, cannot replicate themselves.

Cataracts, heart diseases, cancer, brain damage, and a weakened immune system are all related to aging.

The good news is that the antioxidants present in some foods rich in carotenoids (carrots), flavonoids (onions), vitamins C and E are most effective in fighting off and neutralizing oxygen free radicals.

Copyright (c) 2008 Stephen Lau