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Publication #FCS8935

Carotenoids and Eye Health1

Linda B. Bobroff2

Figure 1. 

Normal vision. AMD blurs the central vision, as you can see in the second image of the two boys.


Credit:

National Eye Institute, NIH/Wikimedia Commons/Public Domain


[Click thumbnail to enlarge.]

Figure 2. 

A scene as it might be viewed by a person with age-related macular degeneration.


Credit:

National Eye Institute, NIH/Wikimedia Commons/Public Domain


[Click thumbnail to enlarge.]

What are carotenoids?

Carotenoids are vitamin A-like compounds found in plants. They have various roles in human health. Some are provitamin A carotenoids that can be converted by our bodies into the active form of vitamin A known as retinol. Beta-carotene is a well-known provitamin A carotenoid.

Some carotenoids cannot be converted into vitamin A. These non-provitamin A carotenoids are phytochemicals (PCs), compounds in plants that are not essential for life but may have health benefits. Approximately 5,000 PCs have been identified. Thousands more may exist in fruits, vegetables, and other plant foods. Certain PCs help reduce risk for major chronic diseases, such as heart disease, stroke, cancer, and type 2 diabetes. Others impact urinary tract, prostate, or eye health. This fact sheet focuses on non-provitamin A carotenoids that promote eye health.

What is AMD?

AMD stands for age-related macular degeneration. The macula is the center part of the retina. It is the part of the eye that helps us see color and high-resolution images in our central vision. Reactions produced by light within the cells that help us see light and color produce toxic by-products. These waste products are normally cleared by other cells within the retina called retinal pigment epithelium (RPE). In macular degeneration, the RPE cells do not work properly. As a result, toxic by-products are deposited into the retina. These deposits are called drusen, and they cause progressive distortion or blurring of the central vision. In the US, AMD is the leading cause of permanent impairment of close-up vision and the ability to read among adults 60 years of age and older. Nearly two million people over the age of 40 in the US have AMD. Another seven million are at high risk for developing the condition.

Exposure to sunlight and free radicals* can harm the macula and cause AMD. It is important to protect our eyes from sunlight by wearing sunglasses when we are outdoors. We can also help protect the macula from free radical damage by having a ready supply of antioxidants in our bodies. The best way to do this is to have a diet rich in colorful fruits and vegetables that provide non-provitamin A carotenoids.

*Free radicals are substances that our bodies produce during everyday chemical reactions. They cause health problems by damaging cell membranes and DNA. Antioxidants, such as vitamin C and carotenoids, keep free radicals under control. We get these antioxidants from the colorful fruits and vegetables that we eat.

What are lutein and zeaxanthin?

Lutein and zeaxanthin are two of the non-provitamin A carotenoids found in fruits and vegetables. They are antioxidants of interest since they are concentrated in the macula of our eyes. Regular consumption of fruits and vegetables that are rich in carotenoids, including lutein and zeaxanthin, may reduce risk for AMD.

Researchers are also studying the effect of nutritional supplements on eye health. Recent studies have found that people at high risk for AMD who took a specially formulated supplement were less likely to develop progression of AMD than those who did not take the supplement. Adding lutein and zeaxanthin to the formulation did not change the effect (Evans & Lawrenson, 2012; AREDS2, 2014). Anyone who is developing AMD should speak with their health care provider before taking any nutritional supplement.

Table 1. 

Common foods rich in lutein/zeaxanthin.

Food

mcg Lutein/Zeaxanthin per 100 g of Food*

Kale, boiled

18,250

Spinach, raw

12,200

Turnip greens, boiled

8,440

Peas, boiled

2,590

Lettuce, green leaf

1,730

Winter squash, baked

1,415

Brussels sprouts, boiled

1,290

Broccoli, boiled

1,080

Sweet corn, yellow, boiled

910

Carrots, raw

260

*mcg = microgram, g = gram

Source: USDA National Nutrient Database for Standard Reference, Release 28 (2016)

What are other risk factors for AMD?

The major risk factors for AMD are being over 60 years of age and smoking. Having a family history also increases risk. Whites and females are more likely than others to have AMD.

Figure 3. 

Being white, female, a smoker, and over age 60 are all risk factors for age-related macular degeneration.


Credit:

BakiBG/istockphoto.com


[Click thumbnail to enlarge.]

What are good sources of lutein and zeaxanthin?

A healthy diet rich in green leafy vegetables and orange vegetables will provide lutein and zeaxanthin as well as other antioxidants that may protect eye health. Table 1 lists several foods that are good-to-rich sources of these carotenoids.

Figure 4. 

Eating foods rich in carotenoids promotes eye health throughout life.


Credit:

ElizabethHoffmann/istockphoto.com


[Click thumbnail to enlarge.]

Summary

A diet rich in colorful fruits and vegetables provides a variety of nutrients as well as phytochemicals that can promote health. Lutein and zeaxanthin are two non-provitamin A carotenoids that may be protective against AMD, the leading cause of permanent central vision loss in older adults. A dietary supplement that contains antioxidants may protect persons at high risk for AMD against the condition. Check with your doctor before taking a dietary supplement for this purpose.

Figure 5. 

It is important for older adults to have an annual dilated eye exam to check for age-related eye diseases.


Credit:

leaf/istockphoto.com


[Click thumbnail to enlarge.]

References

Age-Related Eye Disease Study 2 (AREDS2) Research Group. (2014). Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: The age-related eye disease study 2 (AREDS2) randomized clinical trial. JAMA 309(29): 2005–2015. http://jama.jamanetwork.com/article.aspx?articleid=1684847

Centers for Disease Control and Prevention. (2013). Vision Health Initiative. Common Eye Disorders. Accessed on October 24, 2016. http://www.cdc.gov/visionhealth/basics/ced/index.html

DGAC. (2015). Report of the Dietary Guidelines Advisory Committee (DGAC) on the Dietary Guidelines for Americans, 2015. Washington, D.C. Accessed on October 24, 2016. https://health.gov/dietaryguidelines/2015-scientific-report/

Evans, J. R., & Lawrenson, J. G. (2012). Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration. Cochrane Database Syst. Rev, (6). DOI: 10.1002/14651858.CD000253.pub3

Liu, R. H. (2003). Health benefits of fruit and vegetables are from additive and synergistic combinations of phytochemicals. Am. J. Clin. Nutr. 78(3): 517S–520S.

National Institutes of Health, Office of Dietary Supplements. (2013). Vitamin A: Fact sheet for health professionals. Accessed on June 1, 2015. http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

US Department of Agriculture, Agricultural Research Service, Nutrient Data Laboratory. (2016). USDA National Nutrient Database for Standard Reference, Release 28. Accessed on August 19, 2016. https://www.ars.usda.gov/northeast-area/beltsville-md/beltsville-human-nutrition-research-center/nutrient-data-laboratory/docs/usda-national-nutrient-database-for-standard-reference/

Footnotes

1.

This document is FCS8935, one of a series of the Department of Family, Youth and Community Sciences, UF/IFAS Extension. Original publication date March 2011. Revised October 2016. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Linda B. Bobroff, RD, LD/N, professor, Extension nutrition specialist, Department of Family, Youth and Community Sciences; UF/IFAS Extension, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.