NOW Foods - Walnuts: Another Way to Help Prevent Blindness in the Elderly

Walnuts: Another Way to Help Prevent Blindness in the Elderly

By Greg Arnold, DC, CSCS, July 11, 2005, abstracted from “Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake” in the April 2003 issue of the Archives of Ophthalmology

Age-related macular degeneration (AMD) is the leading causeof irreversible visual impairment and blindness in the UnitedStates and other developed countries throughout the world.¹ More than 200,000 people develop advanced AMD with visualloss every year, and these numbers are continuing to grow.² Unfortunately, the cause of AMD still remains a mystery, with cigarette smoking and advancing age being the only two consistent risk factors.³

Although there are very few options available to treat AMD, nutritional supplementation has offered a lot of promise. Individuals given vitamins C and E,beta carotene, and zinc had a 25% reduced risk of AMD compared with a placebogroup.⁴ Other studies have shown that lutein, an antioxidant found in green, leafy vegetables, can also reduce the risk of AMD.⁵ Finally, even losing weight may reduce AMD risk.⁶

Now a new study published in the Archives of Ophthalmology⁷ has found another nutritious solution to helping prevent AMD: Walnuts.

In the study, known as “The Progression of Age-Related Macular Degeneration Study”, 366 patients aged 60 years and older who had at least one eye with20/200 vision or better and AMD were asked to complete Food Frequency Questionnaires⁸ regarding their diet and lifestyle, especially fat intake.

Researchers found that while high intake of animal fat increased AMD and baked and processed goods doubled the risk of AMD, patients who ate more than one serving of nuts, especially walnuts, per week decreased their risk of AMD by more than 50%. They also found that trans fat, known to decrease “good” cholesterol and increase “bad” cholesterol in the body⁹ while also increasing heart disease risk,¹⁰ increased the risk of AMD.

Researchers went on to suggest that the reason for the protective ability of nuts against AMD is their high content of resveratrol, an antioxidant known to be protective against heart disease and cancer.¹¹ They also cited previous research showing those who ate nuts five or more times per week had a 35% reduced risk of heart disease¹² and a 27% reduced risk of type 2 diabetes.¹³

Greg Arnold is a Chiropractic Physician practicing in Danville, CA. You can contact Dr. Arnold directly by emailing him at mailto:ChiroDocPSUalum@msn.com or visiting his website www.CompleteChiropracticHealthcare.com

Reference:

¹ National Advisory Eye Council. Vision Research—A National Plan: 1999-2003, Vol. 1. A Report of the National Advisory Eye Council. Bethesda, Md: National Institutes of Health; 1999. NIH publication 98-4120

² National Institutes of Health National Eye Institute and Prevent Blindness America. Vision Problems in the US: Prevalence of Adult Vision Impairment and Age-Related Eye Disease in America. Schaumburg, Ill: Prevent Blindness America; 2002

³ Mitchell P, Wang JJ, Smith W, Leeder S. Smoking and the 5-year incidence of age-related maculopathy. Arch Ophthalmol. 2002;120:1357-1363

⁴ 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. Arch Ophthalmol. 2001;119:1417-1436

⁵ Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. JAMA. 1994;272:1413-1420

⁶ Seddon JM, Cote J, Davis N, Rosner B. Progression of age-related macular degeneration: association with body mass index, waist circumference, and waist-hip ratio. Arch Ophthalmol. 2003;121:785-792

⁷ Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake. Arch Ophthalmol. 2003 Dec;121(12):1728-37

⁸ Willett WC, Sampson L, Stampfer MJ, et al. Reproducibility and validity of a semi-quantitative food frequency questionnaire. Am J Epidemiol. 1985;122:51-65

⁹ Mensink RPM, Katan MB. Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. N Engl J Med. 1990;323:439-445

¹⁰ Willett WC, Ascherio A. Trans fatty acids: are the effects only marginal? Am J Public Health. 1994;84:722-724

¹¹ Kris-Etherton PM, Hecker KD, Bonanome A, et al. Bioactive compounds in foods: their role in the prevention of cardiovascular disease and cancer. Am J Med. 2002;113(suppl 9B):71S-88S

¹² Hu FB, Stamfer MJ, Manson JE, et al. Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study. BMJ. 1998;317:1341-1345

¹³ Jiang R, Manson JE, Stampfer MJ, Liu S, Willett WC, Hu FB. Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA. 2002;288:2554-2560