Age related macular degeneration

Chocolate has antioxidant properties for low-density lipoproteins and hence could prevent heart disease. Foods and beverages derived from cocoa beans have been consumed by humans since 460 a.d. Cocoa pods from the cocoa tree (Theobroma cacao) are harvested and the beans removed and fermented. Dried and roasted beans contain about 300 chemicals including caffeine, theobromine, and phenethylamine. Chocolate liquor is prepared by finely grinding the nib of the cocoa bean and is the basis for all chocolate products. Cocoa powder is made by removing part of the cocoabutter from the liquor. Bittersweet chocolate, sometimes called dark chocolate, contains between 15 and 60% chocolate liquor, the remainder being cocoa butter, sugar, and other additives. Milk chocolate is the predominant form of chocolate consumed in the U.S. and typically contains 10 to 12% chocolate liquor. 

The appeal of chocolate is universal, but the pleasures of eating chocolate products may perhaps be tempered by their fat and sugar content. However, in a series of human feeding studies it has been shown that the high proportion of stearic acid in the cocoa butter of chocolate does not adversely affect plasma lipids. Two recent reports of antioxidant activity have increased interest in the health aspects of chocolate an in vitro low-density liposprotein (LDL) oxidation study and a short-term in vivo study. Epicatechin, the major monomeric polyphenol antioxidant in chocolate, and an extract of chocolate liquor were both found to stimulate cellular immune response in vitro. 

Polyphenol consumption as flavonoids has been shown to decrease the risk of heart disease in a cross-cultural epidemiological study. Most recently, an epidemiological study found that Harvard male graduates who ate a moderate amount of chocolate and other candy had a 36% lower risk of death compared with non-candy eaters. The authors speculate that it is the antioxidants present in the chocolate that provide a health benefit. 

The quality of the phenol antioxidants was assessed by Vinson et al. (1999) using the IC50 for LDL + VLDL (very low density lipoprotein) oxidation, with smaller values indicating a higher quality. Quality of the antioxidants was due to free-radical scavenging activity and not chelation as the concentration of polyphenols for 50% inhibition was 1 xM and cupric ion 25 xM in the oxidation medium. There was less percent variation within the groups for this parameter than for the total polyphenol content. The quality order was dark chocolate cocoa milk chocolate. The dark chocolate and cocoa were significantly different from the milk chocolate (p 0.05), but not 

An important antioxidant parameter with respect to head disease is the lipoprotein-bound antioxidant activity. The value for epicatechin, a polyphenol component of chocolate, was 63% greater than the control average, and increase in lag time for the three representative chocolate products was 41%. All beverages, such as wine and tea, that had this antioxidant activity were also found to produce an increase in lag time after ingestion. 

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Ferrara N, Damico L, Shams N, et al (2006) Developmemt of Ranibizumab, an anti-vascular endothelial growth factor antigen binding fragment, as therapy for neovascular age-related macular degeneration. Retina 26 859-870... 

LUTTY G, GRUNWALD J, MAjji A B, UYAMA M and YONEYA s (1999) Changes in choriocapillaris and retinal pigment epithelium (RPE) in age-related macular degeneration. Mol Vis. 5 35-8. 

COOPER D A, ELDRiDGE A L and PETERS J c (1999) Dietary carotenoids and certain cancers, heart disease and age-related macular degeneration a review of recent research , iVMtr Rev, 57, 201-14. 

Snodderly, D.M., Evidence for protection against age-related macular degeneration by carotenoids and antioxidant vitamins. Am. J. Clin. Nutr, 62, 1448S, 1995. 

Beatty, S. et al.. The role of oxidative stress in the pathogenesis of age-related macular degeneration, Surv. Ophthalmol, 45, 115, 2000. 

Landrum, J.T. et al., The macular pigment a possible role in protection from age-related macular degeneration, Adv. Pharmacol, 38, 537, 1997. 

In the Unites States, the daily intake of 3-carotene is around 2 mg/day Several epidemiological studies have reported that consumption of carotenoid-rich foods is associated with reduced risks of certain chronic diseases such as cancers, cardiovascular disease, and age-related macular degeneration. These preventive effects of carotenoids may be related to their major function as vitamin A precursors and/or their actions as antioxidants, modulators of the immune response, and inducers of gap-junction communications. Not all carotenoids exert similar protective effects against specific diseases. By reason of the potential use of carotenoids as natural food colorants and/or for their health-promoting effects, research has focused on better understanding how they are absorbed by and metabolized in the human body. 

Tso and Lam suggested that astaxanthin could be useful for prevention and treatment of neuronal damage associated with age-related macular degeneration and may also be effective in treating ischemic reperfusion injury, Alzheimer s disease, Parkinson s disease, spinal cord injuries, and other types of central nervous system injuries. Astaxanthin was found to easily cross the blood-brain barrier and did not form crystals in the eye. 

There is no cure for age-related macular degeneration and the efficacy of most treatments is low. 

Age-related macular degeneration (AMD) is the primary cause of irreversible vision loss in developed countries (Figs. 60-2 and 60-3). The prevalence increases with age.20 In the United States, 1.75 million people age 40 or older have AMD another 7 million people are at substantial risk of developing it. Because of the rapid aging of the United States population, it is projected that almost 3 million people will develop AMD by 2020.21 The causes of AMD are not completely known (Table 60-7). 

FIGURE 60-3. The scene in Fig. 60-2 as it might be viewed by a person with age-related macular degeneration. (From the National Eye Institute, National Institutes of Health Ref. No. EDS05. Accessed online at http //www.nei.nih.gov/photo/)... 

Comer GM, Ciulla TA, Criswell MH, Tolentino M. Current and future treatment options for nonexudative and exudative age-related macular degeneration. Drugs Aging 2004 21 967-992. Donahue SP, Khoury JM, Kowalski RP. Common ocular infections. A prescriber s guide. Drugs 1996 52 526-540. 

Preferred Practice Patterns from the American Academy of Ophthalmology. Online at http //www.aao.org/aao/education/ library/ppp/index.cfm. Available for keratitis, blepharitis, conjunctivitis, dry eye, and age-related macular degeneration. Wilson SA, Last A. Management of corneal abrasions. Am Fam Physician 2004 70 123-128. 

Schalch, W. (2001). Possible contribution of lutein and zeaxanthin, carotenoids of the macula lutea, to reducing the risk of age-related macular degeneration A review. HKJ Ophthalmology 4 31—42. 

Stringham, J. M. et al. (2008). The utility of using customized heterochromatic flicker photometry (cHFP) to measure macular pigment in patients with age-related macular degeneration. Experimental Eye Research 87 445 153. 

Age-Related Eye Disease Study Research Group (2007), 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. 125 1225-1232. 

Bernstein PS, Zhao DY, Wintch SW, Ermakov IV, and Gellermann W (2002), Resonance Raman measurement of macular carotenoids in normal subjects and in age-related macular degeneration patients, Ophthalmology 109 1780-1787. 

Richer S, Stiles W, Statkute L, Pulido J, Frankowski J, Rudy D, Pei K, Tsipursky M, and Nyland J (2004), Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration The Veterans LAST study (lutein antioxidant supplementation trial), Optometry 75 216-30. 

AREDS Research Group (2001). A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, 3-carotene, and zinc for age-related macular degeneration and vision loss, AREDS Report No. 8. Arch. Ophthalmol. 119(10) 1417-1436. 

Beatty, S., I. J. Murray et al. (2001). Macular pigment and risk for age-related macular degeneration in subjects from a Northern European population. Invest. Ophthalmol. Vis. Sci. 42(2) 439-446. 

Coleman, H. and E. Chew (2007). Nutritional supplementation in age-related macular degeneration. Curr. Opin. Ophthalmol. 18(3) 220-223. 

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