Defend Against DNA DestructionOctober 2012
By Alex Richter
Carotenoids Prevent AMD
Age-related macular degeneration, or AMD, produces more irreversible loss of vision than any other single cause.39,40 As we've seen, AMD is the result of constant assault on retinal cells by light energy, which damages their mitochondrial DNA. The retina is protected by cells packed with lutein, zeaxanthin, and meso-zeaxanthin (formed from lutein in the retina). These three nutrients produce light-absorbing characteristics that protect the light-sensing cells from damage.41-44
But levels of these three nutrients in retinal tissue decline with age, as does their dietary intake, leaving your retina — and your vision— increasingly vulnerable to damage.43,44
DNA damage and repair are essential in understanding age-related macular degeneration. In this case, damage to DNA in mitochondria is the culprit.45,46 Mitochondria generate the power for all of our cells and they are especially important in tissues with high energy demands, such as the heart muscle, nerve tissue, and cells in the retina.
Mitochondrial DNA is highly vulnerable to damage both by light and by oxidant stress, and it has limited repair mechanisms.45,47 Unrepaired mitochondrial DNA damage causes those cells to become unstable, malfunction, and eventually die, leading to the loss of central vision we identify as age-related macular degeneration.47 And the more severe the DNA damage, the more advanced the damage to the retina in AMD.48
You can replace your dwindling stores of retinal pigment, however, by raising your consumption of these xanthophyll nutrients.
Studies show that people with the highest intake of xanthophylls such as lutein, zeaxanthin, and astaxanthin are at 35% less risk of developing the most serious form of AMD, so-called "wet," or neo-vascular disease.49 High xanthophyll intake provides up to a 55% reduction in risk of the less severe, but still disabling, "dry" form of AMD. 49
Unfortunately, you can't get enough of these protective xanthophylls from your diet alone.44 Supplementation at fairly high levels is required in order to restore protective levels of retinal pigment.50
Supplementation studies demonstrate two important and related outcomes of increased xanthophyll consumption. First, people who supplement with these nutrients develop greater concentrations of protective retinal pigments, resulting in improved light protection in their eyes, and lower risk for AMD.41,44,50-52
Second, supplemented people see better. Vision testing shows increased visual acuity in AMD patients taking xanthophyll supplements. One study demonstrated a 5.4 letter improvement on the standard office eye chart,40 while another showed an incredible 1.5 line improvement.53 The ability to see visual contrast improves with xanthophyll supplementation, as does overall retinal sensitivity to visual images.40,52 Xanthophyll supplementation produces objective improvements in the intensity of electrical impulses produced by the retina, a direct measure of increased visual functioning.54
These improvements in retinal pigmentation and visual function have been seen with daily doses of lutein, 12 mg, and zeaxanthin, 1 mg, though 10 to 20 mg have been found to be safe daily doses of each nutrient.41,44,50,51,55 Studies using lower doses of lutein (up to 6 mg/day) generally fail to show any effect.52 Products containing free lutein, as opposed to lutein bound up to other molecules, appear to have superior effectiveness.55 You may be able to protect vital eye structures by supplementing with the omega-3 fatty acid DHA, 800 mg/day as well.41
Big Pharma wants to sell expensive drugs that have only limited benefits (and many side effects) in managing AMD, but experts now agree that supplementation with xanthophylls is "a simple, cost-effective public health intervention that might help to decrease the incidence of AMD."39
Damage to DNA is increasingly being understood to underlie many age-related diseases; it may even be one of the primary causes of aging itself.
Prominent conditions in which we understand the role of DNA damage are cancer, and the eye disease called age-related macular degeneration (AMD). Seemingly disparate, these diseases share a common cause, and are showing encouraging signs of responding to a common nutritional supplement.
The xanthophyll molecules, lutein, zeaxanthin, and astaxanthin are powerful preventers of DNA damage. They stimulate DNA repair mechanisms, which fail with advancing age. Studies are showing that these nutrients may slow the development of cancer, and prevent the onset of eye disease. Safe even in high doses, the xanthophylls deserve a place in your age-prevention toolkit.
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