Eyeworld

EW NEWS & OPINION 16 October 2015 by Vanessa Caceres EyeWorld Contributing Writer day (600 IU/day). The Vitamin D Council suggests a serum 25-hy- droxy vitamin D level to be between 40 and 80 nanograms/mL—and they believe most people should strive for a level of 50 nanograms/mL. The Endocrine Society states that 30 nanograms/mL or more is sufficient. Although vitamin D toxicity is uncommon, it is generally regarded as occurring at levels of 150 nano- grams/mL or higher. Drilling down on D and ophthalmology The connection between D levels and eye disease is still controversial. For example, there have been studies regarding vitamin D and AMD that find some increased risk for AMD when there is vitamin D deficiency, but the studies are not prospective clinical trials, said reti- nal specialist Joseph N. Martel, MD, University of Pittsburgh Medical Center (UPMC) Eye Center. "The hypothesis is that vitamin D has anti-inflammatory properties, and it's suggested that people who are deficient may be more prone to inflammatory episodes that could lead to a higher risk of macular de- generation," he said. "There's not a lot of informa- tion on how vitamin D helps eye health," said registered dietitian Sonya Angelone, MS, RDN, CLT, Marin, Calif. "This seems to be an emerging area." Clinical implications At this point, the evidence doesn't appear to be strong enough for ophthalmologists to advise D3 supplementation or additional sun exposure to their patients, Dr. Martel said. "Perhaps if we noted some- thing in the medical history about being D deficient, we'd tell the primary care physician to get them appropriate supplementation. Out- side of that, it's not the standard of care to target vitamin D levels above the normal range," he said. Ms. Angelone sees a positive with the current spotlight on vita- min D. "The bottom line is that it's The jury is still out on D's role in eye disease, despite research interest V itamin D is a popular discussion topic today for its role in preventing cancer and inflammatory disease. But is there a role for vitamin D in protecting patients against eye disease such as age-relat- ed macular degeneration (AMD) or glaucoma? The answer is not yet clear, a number of ophthalmologists and researchers say. "Every few years, a new vita- min or mineral seems to rediscover itself," said Anat Galor, MD, staff physician, Bruce W. Carter Depart- ment of Veterans Affairs Medical Center (VAMC), Miami, and associ- ate professor of clinical ophthalmol- ogy, Bascom Palmer Eye Institute, Miami. "There's a lot of excitement over vitamin D." Although some questions remain unanswered, there's a clear link between vitamin D3 deficiency (D3 is the form often studied and used in supplementation) and many diseases, including multiple sclero- sis and cancer, said Amber Tovey, community outreach manager at the nonprofit Vitamin D Council, San Luis Obispo, Calif. "Researchers are discovering that vitamin D deficien- cy can make some diseases more severe and that vitamin D can be an important piece in the treatment of some illnesses and diseases," she said. There's a substantial amount of evidence that shows the importance of vitamin D in preventing breast, colorectal, and prostate cancer, and there's also a good deal of research showing a relationship between vi- tamin D and multiple sclerosis, Ms. Tovey added. The interest in vitamin D within ophthalmology and other medical specialties coincides with findings that many people are deficient in D3, Dr. Galor said. The recommended daily allow- ance of vitamin D is 15 micrograms/ Taking a closer look at vitamin D and eye health always important to obtain nutrients from food first. When someone is not able to do that or their needs are increased due to a defect or other reason, supplementation is proba- bly appropriate. Yet it's important to know how much. As research emerges, I'm pleased that physicians are becoming aware of the role of vi- tamin D and supplementing it with other cofactors, such as vitamin K and magnesium," she said. That idea of partnering supplementation with cofactors is something that registered dietitians often can help manage, Ms. Angelone said. Future research There's ripe potential for vitamin D research within ophthalmology. For instance, future research could focus on whether lack of vitamin D leads to more frequent disease or if ade- quate levels have a protective effect. "Lack of vitamin D should be relatively easy to correct with knowledge in the population of how it is synthesized in the skin when the skin is exposed to sunlight, how to increase uptake from eating the right foods, and by dietary supple- ments," said Einar A. Krefting, MD, Eye Department, University Hospital of North Norway, Tromsø. Research should also try to pin- point just how much vitamin D is enough—and when is it too much, said Vincent de Luise, MD, FACS, assistant professor of ophthalmolo- gy, Yale University School of Medi- cine, New Haven, Conn. "Someone who's outside a lot and eats a gen- erally healthy diet may not need as much supplementation as an elderly person who is indoors a lot and eats a poor diet," he said. Although not ophthalmology- specific, there's also the question of how people should try to get vitamin D. Some advocate brief daily sunlight exposure, while others, such as dermatologists, believe in sticking strictly to diet or supple- mentation, Ms. Angelone said. With so much living going on indoors nowadays—be it in the OR, in an office, or in a classroom—and many more people aware of the dangers of sun exposure, the need for supplementation may be real for many, Dr. de Luise said. EW Editors' note: The sources have no financial interests related to this article. Contact information Angelone: sonya.angelone@comcast.net de Luise: eyemusic73@gmail.com Galor: agalor@med.miami.edu Krefting: Einar.Krefting@unn.no Martel: stanleysl@upmc.edu Tovey: atovey@vitamindcouncil.org continued on page 18

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