Sunday, October 5, 2008
Scientists Uncover the Mechanism for Antioxidant Prevention of Blindness
A diet rich in antioxidants is a crucial element in anyone's quest for a long, healthy life. Of the many ailments that antioxidants help prevent, such as heart disease, neurological diseases and a number of cancers, the mechanism by which they prevent age-related blindness has finally been elucidated.
Researchers at the Brigham Young University (BYU) in collaboration with Weill Medical College of Cornell University discovered two destructive processes in the retina of the eye with a combined effect that is greater than the sum of their individual effects; a synergy. The link between these two processes is disrupted by antioxidants, thus preserving irreplaceable photo-receptors and other important retinal cells from degradation.
As we age, damage to our cellular mitochondria, the sources of energy production in cells, is inevitable. A compound called A2E, an undesirable natural byproduct from cellular activity, accumulates in our cells because the body can not degrade or dispose of it. When light exposure creates oxidative stress near A2E, the compound prevents mitochondria from doing their job correctly, resulting in an energy shortage. Without enough energy, the cells can not properly maintain themselves and more A2E builds up. Consequently, this acceleration speeds up the death of the vital retinal cells and makes macular degeneration nearly inevitable once underway.
Using retinal cells from rats, cows and humans, the researchers found in all cases that antioxidants completely counter the oxidative stress and the damage that A2E inflicts on mitochondria. This eliminates the synergy of the two processes; A2E can accumulate without much harm and the mitochondria age at a more normal rate.
While treatment does not exist for macular degeneration, studies have demonstrated high doses of such antioxidants as lutein and zeaxanthin to slow the progression. Lutein and zeaxanthin are the two carotenoids contained within the retina of the eye. They are found primarily in dark green leafy vegetables such as spinach and collard greens. Other antioxidants also play a supportive role.
A diet rich in antioxidants throughout a person's life is a reliable way to prevent or delay this condition as well as the many other diseases associated with a lifetime of oxidative damage.