Posted August 5, 2018: by Bill Sardi
It’s bad enough that the slowly progressive form of macular degeneration robs seniors of their central vision that hampers reading and TV viewing and forces the use of magnifiers. Fortunately, side vision remains. There is no effective treatment for this form of the disease that is commonly called dry macular degeneration (no swelling or hemorrhage). But then the disease can turn worse as blood circulation to the back of the eye is impaired and the compensational growth of new blood vessels to provide oxygenated blood rapidly invade the visual center of the eye (macula) that can result in permanent legal blindness (worse than 20/200 vision). This is commonly called wet macular degeneration.
To put a halt to the invasive blood vessels (called neovascularization or angiogenesis) eye doctors inject chemicals that block the growth of the new blood vessels. The medicine blocks growth factors from triggering the outcropping of these new blood vessels. These needle injections are needed every 30 days or so and are quite effective. However, about 15% of these cases fail to respond to the medicine and progress to legal blindness.
So researchers in Miami, Florida began to search for medicine that would stop growth factors from being produced altogether. There would be no need for the injections. The current treatment, as effective as it may be in staving off vision loss, is akin to allowing a match to be lit and then repeatedly using fire extinguishers.
These researchers took retinal cells in a lab dish and flooded them with vitamin C to a blood level achievable in humans (50 micromole concentration). Vitamin C increasingly reduced growth factor levels over a 5-day period in a “profound” manner. Experiments with lab animals (in vivo) confirmed what was demonstrated in a lab dish (in vitro). Their report was recently published in the journal of Investigative Ophthalmology & Visual Science.
Unlike humans, laboratory mice produce their own vitamin C internally. So these lab animals were genetically altered so they couldn’t produce vitamin C endogenously. Humans are genetically flawed and due to a missing enzyme, cannot internally produce vitamin C as most animals do. So the animal experiment was applicable to the human predicament.
These researchers note that vitamin C concentration in white blood cells in 85-year old adults is about half that of 60-year old adults. Wet macular degeneration is more prevalent with advancing age.
While consumption of vitamin C from dietary sources (oranges, kiwi, papaya, etc.) can achieve the blood level achieved in this experiment, at 60 milligrams of vitamin C per orange, this would require consumption of 6-8 oranges a day (480 mg/day). The recommended intake levels of vitamin C range from 60-200 milligrams, which would be inadequate.
Vitamin C is rapidly excreted from the body in urine flow. To maintain vitamin C levels, consumption of 500 mg of vitamin C 4-6 times a day during waking hours is suggested.
Fortunately, most manufacturers of vitamin C pills have ignored archaic daily intake recommendations (60-200 milligrams/day) and almost exclusively make 500-1000 mg vitamin C pills. Smoking, diabetes, aspirin, diuretics and alcohol deplete vitamin C levels. Eye physicians have no financial incentive in prescribing vitamin C, so it is doubtful whether vitamin C will ever be recommended to patients with the severe form of macular degeneration. Over $2 billion of medicine is injected into eyes for this condition annually. ####
Posted in Dietary Supplements, Vitamins ; No Comments »
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