Vitamin D deficiency is prevalent in many Western nations today, and is responsible for causing illness that touches nearly every aspect of human health. Even proper eyesight is contingent on adequate vitamin D intake as illustrated by research that found a definitive link between increased vitamin D intake and improved eyesight in the elderly.
Researchers from University College London (UCL) in the U.K. made this discovery a couple years ago after reviewing earlier literature on the benefits of vitamin D in reducing and even eliminating amyloid plaques in the brain. They hypothesized that perhaps vitamin D may also eliminate the toxic molecules responsible for causing macular degeneration.
In tests, this hypothesis was confirmed when the researchers administered nominal doses of vitamin D to one-year-old female mice. After being injected every three days with a solution containing safflower oil and about 0.9 micrograms (mcg), or roughly 40 international units (IU), of vitamin D for six weeks, or the equivalent of about 5.75 human years, the mice experienced considerable improvement.
Follow-up tests conducted at the conclusion of the six-week period found that mice given the vitamin solution, as opposed to an oil-only placebo, had a reduced number of inflammation-causing macrophages in their system. Deposits of amyloid beta, a degenerative toxin that can degrade eyesight, were also decreased as a result of the vitamin D.
Since amyloid beta is also has negative effects on brain and heart health, the overall benefits from increased vitamin D intake can also help prevent numerous other illnesses, even in doses far lower than what would be considered therapeutic. Supplementing daily with therapeutic doses of vitamin D, in other words, is "a very simple and effective route to limit disease progression," wrote the authors in their study, which was published in the journal Neurobiology and Aging.
"This research shows how close study of one part of the body can lead scientists to discover new knowledge that is more widely applicable," explained Prof. Douglas Kell, Chief Executive of the Biotechnology and Biological Sciences Research Council (BBSRC), which helped fund the study. "By studying the fundamental biology of one organ scientists can begin to draw links between a number of diseases in the hope of developing preventive strategies."
A different study published in the journal Archives of Ophthalmology back in 2011 made similar observations, having found that people with high levels of vitamin D in their blood were far less likely to suffer age-related macular degeneration. Researchers noted that higher vitamin D levels were associated with about a 60 percent reduced risk of vision loss.