People who get enough vitamin D, or have vitamin D deficiency, are less likely to suffer from age-related macular degeneration, according to a study that appeared in the Archives of Ophthalmology. Bad news for those prone to age-related macular degeneration (AMD). This condition is the foremost cause of blindness in older adults.
Since the publication of that study, the power of vitamin D to impact the health of people who do not receive enough of the vitamin through normal sun exposure or diet has been steadily revealed in study after study. Current research implicates vitamin D deficiency is a major factor in the pathology of at least 17 varieties of cancer. Research also suggest it is linked to heart disease and diabetes. It is also connected to depression, chronic pain, osteoporosis, birth defects and more.
Vitamin D Deficiency May Lead to Visual Impairment
But when it comes to your eyes, there was already an exploration of the impact of vitamin D on eyesight decades ago. It was and still is, largely ignored by the medical community.
Arthur Alexander Knapp, MD began reporting on research with animals and humans in the 1930s. In 1946, he published a paper called The Eye as a Guide to Latent Nutritional Deficiencies. In the paper he detailed his observations and treatment of navy personnel in the South Pacific. One of Knapp’s discoveries was that a severe form of myopia (nearsightedness) responded to treatment with vitamin D and calcium. In over 50% of his patients, adding vitamin D and calcium stopped or greatly retarded the progression of myopia. Also, more than 30% had improvements in their vision.
Knapp used before and after plaster casts. He proved that vitamin D and calcium supplementation actually changed the shape of the eye. (Note: Knapp often prescribed as many as 50,000 IU of D daily. This is not something one should do without medical supervision.) In experiments with animals, Knapp and a colleague induced vitamin D and calcium deficiency. They discovered that the animals developed eye problems within 6 weeks. Full blown cataracts appeared after six months.
Weston A. Price, DDS, was also ahead of his time in his recognition of the critical role of vitamin D in human nutrition. Price studied isolated cultures during the 1940s. He found that those who ate traditional diets had much stronger, cavity free teeth. They also had broader smiles, fuller jaws and sunnier dispositions. Their diets had 10 times the amount of vitamin A and vitamin D than found in that of the standard American diet at that time. That’s because they seemed to instinctively seek out foods with these fat soluble vitamins. These are foods many people don’t eat today. Such foods include intestine, skin, oily fish, organ meats and insects.
Many people are supplementing with 1,000 to 2,000 IU of vitamin D3 daily. But according to the Vitamin D Council that may not be enough. The Vitamin D Council suggests taking 5,000 IU of vitamin D3 every day for three months. Then, get a 25-hydroxyvitamin D test. Optimal blood levels are between 50-80 ng/mL year-round. Blood testing is the only way to know for sure whether your regimen is appropriate.
It’s hard to know exactly how much vitamin D your body is making from sun exposure. It depends on factors like what latitude you live at, your skin color and how much skin you expose for how long. And your needs may change according to the seasons. Your needs may also alter depending on your age, health and weight. Adjust your dosage up or down according to your results.
Don’t let a vitamin D deficiency put you at risk for vision loss as you age. Get your vitamin D levels checked so you can be sure you are taking enough supplemental vitamin D to keep your blood levels in a safe range.