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Practical Approaches to Clinical Nutrition

Practical approaches to Clinical Nutrition

Appropriate nutritional intake is a necessity to nourish the body with the proper vitamins and minerals, thus promoting optimal health. Many Americans, however, do not obtain sufficient vitamins from their everyday diet.

Practical approaches to Clinical Nutrition Appropriate nutritional intake is a necessity to nourish the body with the proper vitamins and minerals, thus promoting optimal health. Many Americans, however, do not obtain sufficient vitamins from their everyday diet. For example, the average American diet provides less than 2mg of lutein. In addition, factors such as lack of exercise and obesity further contribute to nutritional deficiencies, which negatively impacts ocular health.

Dry eyes, age related macular degeneration (AMD), retinitis pigmentosa, cataracts and vascular retinopathies are among some of the ocular conditions linked to specific nutrients. In regards to comprehensive management of these conditions, it has become increasingly important to educate the patient on lifestyle modification, as well as proper diet and appropriate nutritional supplementation.

AMD is the leading cause of vision loss in the elderly population. Although the exact pathogenesis of AMD has not been clearly elucidated, various risk factors have been identified. Cumulative oxidative stress has been shown to play a contributory role, leading to apoptosis of the photoreceptor. A number of studies have demonstrated the benefits of high levels of antioxidants on AMD. To date, the Age Related Eye Disease Studies (AREDS & AREDS 2) are the largest evidence-based medicine studies documenting the effectiveness of nutritional supplements for slowing the progression of moderate AMD. The results of the original AREDS showed that high intake levels of vitamin C, vitamin E, beta-carotene and zinc lowered the risk for disease progression by 25% in patients with intermediate or advanced AMD.

Yet, adverse affects associated with the original AREDS formula need to be taken in consideration. The original AREDS study showed that zinc was associated with increased risks of genitourinary complications. High levels of beta-carotene have been found to lead to lung carcinogenesis among smokers. These safety considerations played a significant role in the testing parameters for AREDS2 study. In addition, further analysis of the original AREDS study suggested that dietary intake of omega 3, lutein and zexanthin have a beneficial impact on AMD. Higher dietary intake of Omega 3 was inversely correlated with geographic atrophy; while higher dietary intake of both lutein and zeaxanthin was associated with decreased likelihood of AMD. The AREDS 2 study was designed to assess the efficacy & safety of a refined the original AREDS formula on the moderate stage of AMD.

The primary results of AREDS2 revealed that, when comparing the control group (the original AREDS formula) to the treated arms (addition of lutein/zeaxanthin; omega-3; or combination of lutein/zeaxanthin to omega-3), there was no significant reduction in the risk of progression toward advanced AMD. The AREDS 2 study was a complex design, involving secondary randomization and secondary analyses. Hence, the true benefits of added nutrients were only revealed upon further analysis. In fact, the addition of lutein and zeaxanthin was associated with a decrease in the risk of progression to AMD. This was more apparent among those subjects who had lower dietary intake for lutein and zeaxanthin. Moreover, when evaluating specific subgroups, it was determined that the addition of lutein & zeaxanthin to an AREDS formula without beta-carotene, yielded further reduction in the risk of progression to advanced AMD.

A growing body of evidence supports the used of nutritional supplementation as a preventive management strategy for a number of ocular conditions, including AMD. Implementing them may slow functional and/or structural damage associated with the disease. It is crucial, therefore, to properly educate our patients about lifestyle modifications and individual nutrition intake, as well as proper nutritional supplementations.

References

    1. Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta-carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001 Oct;119(10):1417-36.
    2. Age-Related Eye Disease Study 2 Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA. 2013 May 15:309(19):2005-15.
    3. SanGiovanni JP, Chew EY, Agrón E, et al. The relationship of dietary omega-3 long-chain polyunsaturated fatty acid intake with incident age-related macular degeneration: AREDS report no. 23. Arch Ophthalmol. 2008 Sep;126(9):1274-9.
    4. AREDS study research group. The Relationship of Dietary Carotenoid and Vitamin A, E, and C Intake With Age-Related Macular Degeneration in a Case-Control Study AREDS Report No. 22. Arch Ophthalmol. 2007;125(9):1225-1232.
    5. Moeller SM, Voland R, Tinker L, et al. Associations between age-related nuclear cataract and lutein and zeaxanthin in the diet and serum in the Carotenoids in the Age-Related Eye Disease Study, an Ancillary Study of the Women’s Health Initiative. Arch Ophthalmol. 2008 Mar;126(3):354-64.
    6. Berson EL, Rosner B, Sandberg MA, Weigel-DiFranco C, et al. Clinical Trial of Lutein in Patients With Retinitis Pigmentosa Receiving Vitamin A. Arch Ophthalmol 2010;128:403-411. Arch Ophthalmol 2010;128(4):403-411
    7. Ommen GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta-carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996;334(18):1150-1155.
    8. The Alpha-Tocopherol Beta Carotene Cancer Prevention Study Group The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med 1994;330(15):1029-35.

DianaShechtmanNewSm-1Diana Shechtman, O.D. F.A.A.O. is an associate professor of optometry at Nova Southeastern University College of Optometry, where she serves as an attending optometric physician at the eye institute and diabetic/macula clinic. Dr. Shechtman is a member of the American Optometric Association (AOA) and she is a fellow of the American Academy of Optometry (AAO), as well as the Optometric Retinal Society (ORS). Her area of interest has centered on retinal disease and other ocular pathologies. She has participated in various research projects, authored numerous posters and publications. She is a member of the editorial board for Optometry times and Review of Optometry, where she co-authors the monthly “Research Review” column. She also is also a member of the macular degeneration association and ocular nutrition society advisory board. She has lectured on a local, national & international level on areas in retinal disease.

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