Cells, like everything else, are composed of many different types of molecules, and molecules are made up of one or more atoms of one or more basic elements (like carbon, oxygen, etc). They are joined by chemical bonds. As you might know from high school science, atoms have a nucleus (centre), neutrons (electrically neutral particles), protons (positively charged particles) and electrons (negatively charged particles). The number of protons in an atom’s nucleus determines the number of electrons (negatively charged particles) you will find surrounding the atom. Electrons are involved in chemical reactions and they hold atoms together to form molecules. Electrons surround, or “orbit” an atom in one or more “shells”.
The innermost shell is full when it has two electrons. When the first shell is full, electrons begin to fill the second shell. When the second shell has eight electrons, it is full, and so on. The number of electrons in an atom’s outer shell is key to its chemical behaviour. If it has a full outer shell, it will not usually react chemically with other substances - it is stable or “inert”. Atoms “want” to be stable and they will try to fill the outer shell with electrons by:
- gaining or losing electrons to fill or empty the outer shell
- sharing electrons by bonding together with other atoms (forming new molecules).
How Free Radicals are Formed
Normally, the bonds between electrons don’t split and leave a molecule with an unpaired electron, but when bonds are weak it can happen and they do split. That’s when free radicals are formed. Free radicals are very unstable and react quickly with other compounds, trying to capture the needed electron to gain stability. Generally, free radicals attack the nearest stable molecule, “stealing” an electron from it. When the “attacked” molecule loses its electron, it becomes a free radical, and a chain reaction begins that can damage living cells.
Some free radicals are necessary for life and some are created during normal metabolism. Sometimes our immune system creates free radicals on purpose to neutralize viruses and bacteria. Lifestyle and environmental factors, such as pollution, radiation, smoke, herbicides and pesticides can also cause the formation of free radicals.
Normally the body can handle free radicals. It has a number of mechanisms to minimize free radical damage and to repair damage that does occur, but if antioxidants are unavailable, or if free radical production becomes excessive, cells will be disrupted.
Free radical damage accumulates with age and is thought to be a major factor in age-related diseases, conditions and in the speed of aging itself.
How Antioxidants Prevent Free Radical Damage
Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-“stealing” chain reaction. Antioxidant nutrients don’t become free radicals by donating an electron because they are stable either way. They help prevent cell and tissue damage that can lead to health problems and disease.
Fresh berries, berry extracts and juices are excellent sources of antioxidant nutrients.
ORAC value
The Oxygen Radical Absorbance Capacity, or ORAC value of foods, is a measurement of antioxidant levels. The higher the ORAC value, the more antioxidant power a food has. Berry ORAC values top those of many other fruits and vegetables, including oranges, grapefruit, cherries, plums, Brussels sprouts, broccoli and spinach. Blueberries, with an ORAC value of 5,486, have one of the highest antioxidant levels. Right behind are blackberries with an ORAC value of 4,654; strawberries at 3,520 and raspberries, 2,789.