Nutrition and Eye Health

Nutrition and Eye Health Dr. Betty J. Larson, LRD, FADA Concordia College Moorhead, MN 56562 Objectives • Researchers have suggested that six nutrients are correlated with maintaining eye health – Vitamins C and E, carotenoids lutein, zeaxanthin, and beta-carotene and the mineral zinc. • On-line dietary risk assessment called Eye on Nutrition can be accessed at www.aoa.org/EyeOnNutrition Cataracts • A leading cause of blindness worldwide and the most costly item on the Medicare budget in the US. • Risk factors include smoking, exposure to sunlight, diabetes, and inflammation. Cataracts • Cataracts develop when lens proteins are damaged which causes them to become cloudy or opaque. • Oxidative stress, principally from ultraviolet light is thought to play a crucial role in development of cataracts. • Two types “nuclear” and “cortical” according to their location. Less common is subcapsular Age-Related Macular Degeneration • A leading cause of acquired blindness and vision • • • impairment among elderly Americans. Prevalence increases dramatically with age Occurs as “wet” or “dry” Dry AMD is characterized by perceptual “holes” or inconsistencies in the center of the visual field. This is due to a breakdown of cells and membranes in the macula, a tiny area at the center of the retina in the back of the eye. The macula contains a dense accumulation of cone cells which are responsible for providing color and fine detail in the center of the visual field. • Macular Degeneration Continued • When retinal cells are lost, they do not regenerate, thus the vision loss from macular degeneration is irreversible. • Only proven way to delay progression of dry AMD is vitamin/ mineral intake. Risk factors for AMD • • • • • • Increased age Female gender Lighter iris color Race Smoking Sunlight Exposure Vitamin C and Cataracts • Sources of C include citrus fruits, potatoes, berries and green veg. • As an antioxidant, vitamin C is useful in protecting the lens against free radical reactions triggered by UV light. • C is water-soluble so penetrates the layers of the lens to protect the area. • Lens has 20x more C than the plasma. Vitamin C and Cataracts • Researchers have found consistent associations between higher dietary or plasma vitamin C and a reduced risk for cataracts. – Nurses Health Study – Beaver Dam Eye Study Vitamin E and Cataracts • Vitamin E is found in the membranes of all cells where it protects them from oxidative damage. • Not concentrated in the eye like C but a higher intake can increase the amount of E in the retina. MARGARINE, OILS, SEEDS, NUTS CONTAIN VITAMIN E Vitamin E and Cataracts • Mixed results from studies on Vitamin E and the eye. • Researchers reported from the Beaver Dam Eye Study there was a beneficial correlation between blood vitamin E concentration and cataract risk. • Low blood vitamin E concentration has also been associated with an increased risk of cataracts. Cataracts and Other Nutrients • Australian researchers found a reduced risk of nuclear cataracts with higher dietary intakes or other nutrients. Vitamins and AMD • Concentrations of vitamin E have been found to be protective against age-related macular disease in some observational studies but not in all studies. • Similarly observational studies have generally not led to correlations between vitamin C and AMD whether based on plasma concentration or dietary intake. Clinical Trials and AMD • In the Age-Related Eye Disease Study by the National Eye Institute tested antioxidant on AMD and cataracts researchers found antioxidants retarded progression of AMD • Supplement given of C, E, beta-carotene, zinc. Carotenoids in Eye Health • The eye selectively and exclusively concentrates the yellow-color carotenoids lutein and zeaxanthin in a layer of retinal tissues than overlies the macula region. Carotenoids in the Retina • Researchers believe that these two carotenoids specifically absorbs near-to-UV blue light, the highest-energy and therefore the most damaging wavelength of light that actually reaches the retina. • Another theory is that they serve as an antioxidant defense against free radicals. Macular Pigment Density • Capacity to increase macular pigment density has been demonstrated using spinach as a lutein-rich food or corn as a zeaxanthin-rich food. • Eye Disease Case-Control Study researchers found AMD risk was significantly lower with increasing serum concentrations of lutein + Zeaxanthin. Sources of Lutein in mg in 1Cup • • • • • • • • Spinach cooked 13.3 Raw Cabbage 10.2 Broccoli cooked 3.4 Peas cooked 3.2 Raw Spinach 1.8 Raw Broccoli 1.4 Raw Greens 1.1 Green Pepper .9 Sources of Zeaxanthin in mg of 1C • • • • • • Orange Pepper 1.5 Corn .8 Cooked Spinach .4 Romaine .1 Raw Spinach .1 Tangerine .1 Sources of Lutein + Zeaxanthin in mg in 1C • • • • • • • • Kale 26.5 Spinach cooked 12.6 Broccoli 4.0 Spinach raw 3.6 Green Peas 2.2 Raw Broccoli 2.1 Corn 1.5 Brussels Sprouts 1.1