April 14, 2011
Study Finds High Vitamin D Levels May Lower Macular Degeneration RiskTopics: General Health
Age-related macular degeneration is a chronic, late-onset disease that degrades the eye's retina over time and results in degeneration of the macula, the central portion of the retina that allows for focused, precise vision. It is the leading cause of adult irreversible vision loss and affects about 8.5 million Americans aged 40 and older. Now, results of a study published this week by the Archives of Ophthalmology suggests that women with early-onset age-related macular degeneration (AMD) may be able to prevent or slow the process of the ailment by taking high levels of vitamin D supplements.
[...] Amy E. Millen, Ph.D., from the University at Buffalo in New York, and colleagues investigated the association between serum 25(OH)D concentrations and the prevalence of early AMD. Participants in the Carotenoids in Age-Related Eye Disease Study had their AMD status assessed using stereoscopic fundus photographs. Baseline serum 25(OH)D serum samples from 1,313 women with ocular and risk factor data were evaluated, and odds ratios were estimated for the 241 women who developed early AMD.Read more.
The researchers found that there was no significant association between early AMD and serum 25(OH)D in the fifth compared to the first quintile. ... After adjusting for body mass index and recreational activity, the correlation was attenuated. Vitamin D intake from foods or supplements was associated with lower likelihood of early AMD in women younger than 75.
"Vitamin D status may significantly affect a woman's odds of developing early AMD. More studies are needed to verify this association prospectively as well as to better understand the potential interaction between vitamin D status and genetic and lifestyle factors with respect to risk of early AMD," the authors write.
As I've previously noted, in order to get high levels of vitamin D one needs to take a supplement. As for which supplement to use, vitamin D3 is the recommended form. There are 5 forms of vitamin D. The two major forms are vitamin D2 (ergocalciferol) and D3 (cholecalciferol). Both forms are present in human nutritional supplements. When our skin comes into contact with UVB radiation, it synthesizes only vitamin D3. Both of these forms are prohormones, precursors to the vitamin D hormone that goes on to perform all of the beneficial processes that have been mentioned. However, the vitamin D3 form is about 3 times more effective at creating the vitamin D hormone and its duration of action is longer that the D2 form. Supplementing with vitamin D3 would be the wiser choice.
I include D3 in my own supplement regimen and purchase it online from Vitacost (a company I have no affiliation with), which I have found to offer the most effective product for the most reasonable cost. If you include a regular vitamin-mineral supplement in your own daily routine, you should use a product that includes calcium and magnesium. It is also important to know that although most multivitamin supplements contain only 400-800 IU of vitamin D, and this is only 10 to 20 percent of what is necessary for optimal physiologic function. For people unable to obtain 20-30 minutes of full-body sun exposure on an almost daily basis, it has become clear that high-dose vitamin D supplementation (a dosage range of at least 3,000-5,000 IU per day) is necessary to ensure that physiologic needs are met, and so that optimal health can be obtained and maintained.
Interestingly, when your physician gives you a prescription for vitamin D he or she is giving you a form of vitamin D2 (brand names Driscol and Calciferol), which is not only vastly inferior to the over-the-counter preparation but is also far more expensive (Over-the-counter: $2 per month/Prescription: $70 per month). So be sure to take the effective human form, vitamin D3 or cholecalciferol, not the prescription form - ergocalciferol, or vitamin D2.
Image credit - Wolf Eye Clinic (AMD - What you see)
Also posted at Hyscience
Posted by Richard at April 14, 2011 2:01 PM
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