Practice Policy Update Regarding COVID-19

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Adding powerful antioxidants to your diet can improve your eye health.

There’s no substitute for the quality of life good vision offers. Adding certain nutrients to your daily diet—either through foods or supplements—can help preserve your vision. Researchers have linked eye-friendly nutrients, such as lutein and zeaxanthin, vitamin C, vitamin E, and zinc, to reduce the risk of certain eye diseases.

  • Lutein & Zeaxanthin
    Lutein and zeaxanthin are important nutrients found in green leafy vegetables, as well as other foods, such as eggs. Many studies show that lutein and zeaxanthin reduce the risk of chronic eye diseases, including age-related macular degeneration and cataracts.
  • Vitamin C
    Vitamin C (ascorbic acid) is an antioxidant found in fruits and vegetables. Scientific evidence suggests vitamin C lowers the risk of developing cataracts. Also, when taken in combination with other essential nutrients, it can slow the progression of age-related macular degeneration and visual acuity loss.
  • Vitamin E
    Vitamin E is a powerful antioxidant found in nuts, fortified cereals, and sweet potatoes. Research indicates it protects cells in the eyes from unstable molecules called free radicals, which break down healthy tissue.
  • Essential fatty acids
    Fats are a necessary part of the human diet. They maintain the integrity of the nervous system, fuel cells and boost the immune system. Research shows omega-3 fatty acids are important for proper visual development and retinal function.
  • Zinc
    Zinc is an essential trace mineral or “helper molecule.” It plays a vital role in bringing vitamin A from the liver to the retina in order to produce melanin, a protective pigment in the eyes. Zinc is highly concentrated in the eye, mostly in the retina and choroid, the vascular tissue layer lying under the retina.

Written in partnership with AOA members Stuart Richer, O.D., Ph.D., and Steven Newman, O.D. The AOA acknowledges the support of Kemin.

Emerging research

In the last 20 years, eye health research has linked diet and nutrition with a decreased risk of age-related macular degeneration (AMD). A major clinical study of older adults concluded that taking an antioxidant vitamin or mineral supplement significantly reduced the risk of advanced AMD progression in some people. Additionally, today there is significant evidence that vitamin D plays a role in preventing AMD.

AREDS made it clear

The Age-Related Eye Disease Study (AREDS) was a major clinical trial sponsored by the National Eye Institute. It enrolled 3640 subjects, age 55 to 80, and was released in October 2001. This landmark study provided evidence that nutritional intervention in the form of supplements could delay the progression of AMD. The study concluded that taking an antioxidant vitamin or mineral supplement reduced the risk of advanced AMD progression by about 25 percent and showed a 19 percent reduction in visual acuity loss in some of the subjects.

The case for Lutein and Zeaxanthin

It was not clear in the original AREDS report which vitamin, mineral or combination of nutrients was responsible for reducing the risk of AMD. When the study was planned, the lutein and zeaxanthin carotenoids that constitute the macular pigment were not assessed because they were not commercially available. Since then, several studies have provided growing evidence specific to the beneficial role of lutein and zeaxanthin intake, and their positive effect on eye health and AMD risk reduction. The AREDS Report No. 22 published in 2007 described the relationship between dietary intake of various nutrients and AMD among the AREDS subjects. This report concluded that high dietary intake of lutein and zeaxanthin is associated with a reduction in the risk of geographic atrophy, advanced AMD, and large or extensive intermediate drusen, the waste byproducts of cellular metabolism (activity).

New study builds on long term nutrient benefits

A follow up to the original AREDS trial, AREDS2, began in June 2008. This multi-centered, five-year study builds on a multitude of existing science supporting lutein and zeaxanthin’s role in maintaining healthy eyes. It is the largest human clinical trial to evaluate lutein, zeaxanthin, and omega-3 fatty acids supplementation and includes 4,000 patients at high risk for AMD. The study is focusing on the protective effects lutein (10 mg/day), zeaxanthin (2 mg/day), and omega-3 fatty acids (1 g/day) have against AMD, as well as the link between nutrition and macular pigment optical density, cataract development, and visual function

Nutrition

Many doctors of optometry are expanding their traditional roles to include other areas that affect eye health, such as nutritional education. Research has shown that certain nutrients can delay the development and progression of cataracts and AMD. These are two of the leading causes of blindness and visual impairment for millions of aging Americans. Nutrition may be particularly important in treating AMD. Currently, treatment options after diagnosis of this condition are limited. Also, people who suffer from dry eye, an increasing problem due to the visual demands of digital devices, can often benefit from nutritional supplements.

Nutrition and cataracts

Cataracts are a leading cause of visual impairment among aging Americans and a key quality-of-life issue. Cataract removal is the most common surgical procedure performed in the U.S., accounting for more than 2 million procedures each year.

Experts theorize that if the progression of cataracts could be delayed by 10 years, annual cataract surgeries would decrease by 45 percent. Nutrition is one promising way to prevent or delay the progression of cataracts.

Cataracts develop when the proteins in the lens of the eye are damaged, causing them to become translucent or dense or opaque. There are three major types of cataracts, depending on where they are located in the lens: nuclear, cortical and posterior subcapsular.

Several uncontrollable factors may increase the risk of developing cataracts, including:

  • Age.
  • Family history.
  • Ethnicity (African Americans have a higher risk of developing and becoming blind from cataracts.)
  • Some studies also suggest that women may be at a slightly higher risk than men.

However, research shows we can control several risk factors for cataracts by changing certain behaviors, including:

  • Not smoking.
  • Reducing exposure to sunlight by wearing UVA/UVB protective eyewear and wide-brimmed hats.
  • Controlling other diseases such as diabetes.
  • Eating a healthy diet.

What is nutrition’s link to cataracts?

Several research studies show that the antioxidant properties of vitamins C and E may protect against the development and progression of cataracts. Early evidence also suggests that the carotenoids lutein (pronounced loo-teen) and zeaxanthin (pronounced zee-uh-zan-thin), which are also antioxidants, may also help protect against cataracts.

Research on antioxidant vitamins and cataracts

Some recent studies have shown that antioxidants vitamins C and E may decrease the development or progression of cataracts:

  • The Nutrition and Vision Project found that higher intakes of vitamin C  reduced the risk for cortical and nuclear cataracts. Results also showed that people who used vitamin C and E supplements for more than 10 years decreased the progression of nuclear cataracts.
  • A recent analysis of results from a national dietary study (Second National Health and Nutrition Examination Survey) found that higher levels of vitamin C in the diet were associated with a lower risk of cataracts.
  • In the Nurses’ Health Study, cataract surgery was lower among women who took vitamin C supplements for 10 years or longer.
  • The Roche European American Cataract Trial found that taking an antioxidant supplement with vitamins C and E and beta-carotene led to a small decrease in the progression of cataracts in less than three years.
  • In the Longitudinal Study of Cataract, taking a vitamin E supplement for at least a year was associated with a reduced risk of nuclear cataracts becoming more severe.
  • The five-year follow-up to the Beaver Dam Eye Study showed that people using multivitamins or any supplement containing vitamins C and E had a reduced risk for nuclear and cortical cataracts.

Research—Lutein, and Zeaxanthin and cataracts

Lutein and zeaxanthin are promising nutrients in the fight against cataracts. Lutein and zeaxanthin are the only carotenoids found in the eye. Several recent studies have examined these two nutrients and the risk of developing cataracts:

  • The Nurses’ Health Study found that people taking high amounts of lutein+zeaxanthin had a reduced need for cataract surgery. On average, people took around 6 milligrams (mg) of lutein+zeaxanthin each day.
  • The Health Professional’s Follow-Up Study also found that eating foods with high amounts of lutein+zeaxanthin (6.9 mg per day) led to a reduced need for cataract surgery.
  • The five-year follow-up to the Beaver Dam Eye Study showed that people with the highest intakes of lutein+zeaxanthin had a significantly lower risk for developing new cataracts than those with the lowest intakes.
  • A recent study in England found that people with the highest amount of lutein in their blood, from regularly eating food high in lutein, had the lowest risk for posterior subcapsular cataracts.

What you need to know

Given the positive association between nutrition and cataracts, it’s probably a good idea to increase the amount of certain antioxidants in your daily diet. Eating five servings of fruits and vegetables each day, as currently recommended by the National Cancer Institute and U.S. Department of Agriculture, can provide more than 100 mg of vitamin C and 5 to 6 mg of carotenoids, including lutein and zeaxanthin. Eating two servings of nuts and seeds can provide 8 to 14 mg of vitamin E. See the tables below for good food sources of these nutrients.

However, the majority of people in the U.S. are not eating five servings of fruits and vegetables and good food sources of vitamin E each day. The average daily diet contains approximately 100 mg of vitamin C, 1 to 7 mg lutein and zeaxanthin, and 8 mg vitamin E. In the studies mentioned here, the consumption levels associated with cataract benefits were considerably higher than the current average intake. If you find it difficult to increase the level of these antioxidants and carotenoids in your diet, consider taking multivitamin/mineral and eye health supplements containing these nutrients.

Nutrient values tested

NutrientRecommended dietary allowance (RDA) 1,2Levels associated with health benefitPercent of people getting less than 100% of RDA 1,2,3,4
Vitamin C90 mg for men
75 mg for women
+35 mg for smokers
≥ 250 mgMore than 50% of individuals
Vitamin E*22 IU (15 mg) natural
33 IU (30 mg) synthetic
≥ 100 IUMore than 90% of individuals
Lutein and Zeaxanthin**6 mgAverage intake
per day 1.7 mg

*The Food and Nutrition Board reported two different RDA values for vitamin E depending on synthetic or natural source.
**There is no RDA for lutein, zeaxanthin, and beta-carotene.

  1. Dietary Reference Intakes for Vitamin C, Vitamin E, and Carotenoids. Institute of Medicine, 2000.
  2. Dietary Reference Intakes for Vitamin A and Zinc. Institute of Medicine, 2001.
  3. Vitamin and mineral data were obtained from CSFII, 1994-1996. Values correspond to all individuals.
  4. Carotenoid data was gathered from NHANES III, 1988-1994.

Food sources

Most fruits and vegetables are excellent sources of vitamin C. Oranges, grapefruit, strawberries, papaya, green peppers, and tomatoes are particularly high in vitamin C.

Vitamin E is more difficult to obtain from food sources alone since it is found in very small quantities in foods. Good food sources include vegetable oils (including safflower and corn oil), almonds, pecans, wheat germ, and sunflower seeds.

Lutein and zeaxanthin are found together in many food sources. Dark green leafy vegetables are the primary source of lutein and zeaxanthin, but lesser amounts are in other colorful fruits and vegetables, such as broccoli, orange peppers, corn, peas, persimmons, and tangerines.

FoodAmountVitamin E
Almonds1/4 cup9.3 (13.9 IU)
Sunflower seeds1/4 cup5.8 (8.7 IU)
Safflower oil1 tbsp4.7 (7.0 IU)
Peanuts1/4 cup3.3 (4.9 IU)
Peanut butter2 tbsp3.2 (4.8 IU)
Corn oil1 tbsp2.8 (4.2 IU)

Source: USDA Nutrient Database for Standard Reference Release 13

Good food sources of vitamin C (mg/serving)

FoodAmountVitamin C
Orange juice, fresh squeezed1 cup124
Grapefruit juice, fresh squeezed1 cup94
Papaya1/2 medium94
Cantaloupe1/4 melon86
Orange1 medium80
Green peppers, raw chopped1/2 cup67
Tomato juice1 cup44
Strawberries1/2 cup43
Broccoli, raw chopped1/2 cup41
Grapefruit1/2 medium40

Source: USDA Nutrient Database for Standard Reference Release 13

Good food sources of Lutein and Zeaxanthin (mg/serving)

Food/Serving
(1 cup)
Lutein and ZeaxanthinLuteinZeaxanthin
Kale20.5 – 26.5*1.1 – 2.2*
Collard greens15.35.1
Spinach3.6 – 12.6*1.7 – 13.3*0.5 – 5.9*
Turnip greens12.10.4
Broccoli2.1 – 3.5*1.4 – 1.6*
Corn, yellow1.4 – 3.00.60.9
Peas, green2.32.2
Orange pepper1.7
Persimmons1.40.8
Tangerine0.50.2

*depending on variety and preparation

Sources: USDA-NCC Carotenoid Database, 1998, USDA Food Nutrient Database for Standard Release 13
Hart and Scott, 1995

Nutrition and AMD

AMD is an acquired eye disorder and a leading cause of legal blindness in people over age 60.1 AMD affects the macula (the central part of the retina), which is responsible for providing the clear, sharp vision needed for reading, writing, driving and other visually demanding activities.

The severity of this condition varies depends on the individual patient. Many people with AMD lose some central vision in one or both eyes.

Approximately 90 percent of patients with AMD have a non-exudative (or dry) form of the disease. In this form of the disease, dry, atrophic scars develop in the macular area. Typically, non-exudative AMD patients lose vision gradually.

Only 10 percent of patients develop an exudative (or wet) form of the disease. In the wet form of the disease, fluid beneath the retina leaks. Compared with non-exudative patients, exudative patients lose central vision more rapidly.

Patients with exudative AMD who are identified early in the disease process2 can be treated managed with laser photocoagulation. Other treatments include photodynamic therapy and surgical transplantation of the macula.

Research suggests that AMD development is linked to depleted macular pigment. This retinal layer efficiently filters out harmful blue wavelengths of light. It also reduces the amount of free radicals in the macular area, which can cause oxidation of cell membranes. 3

Researchers theorize that certain antioxidant compounds reduce the effect of these free radicals on the macular pigment and, consequently, may affect the development of AMD. 4,5,6 These antioxidants, known as carotenoids, build and maintain the thickness of the retinal pigment layer.

Carotenoids, such as beta-carotene, lutein, and zeaxanthin, are a family of colored compounds found in fruits and vegetables. We consume and use 14 different carotenoids in our diet. Lutein and zeaxanthin-found in dark, leafy green vegetables such as spinach, collard greens and kale-are particularly effective in the retinal pigment layer. Studies show that a diet high in these materials have some effect on delaying the advancement of AMD. 7,8,9,10

Taking synthetic supplements that contain these carotenoids, along with vitamins C and E and zinc, has been proven to limit the disease in patients with advanced signs and symptoms of AMD. 11 Also, because the method of food preparation can impact your body’s ability to fully benefit from these natural sources of carotenoids, taking supplements can help assure people are getting the proper levels.

Antioxidants cannot reverse the damage already caused by AMD, but they may prevent or slow the progression of AMD in certain patients. Dietary supplementation of antioxidants, taken with vitamins C and E and zinc, may be most appropriate for people who:

  • Show early evidence of AMD.
  • Are over age 50.
  • Have a family history of AMD.
  • Don’t have enough vitamins and minerals in their diet.

Additional studies and data are needed to further define what nutritional and antioxidant therapies and dosages can prevent AMD.

Other risk factors for AMD, although not thoroughly understood, may include smoking, alcohol intake, excessive sunlight and high total cholesterol levels. The American Optometric Association recommends patients reduce their risk of AMD by wearing appropriate sun protection to limit ultraviolet exposure, stop smoking, moderate alcohol consumption, maintain a nutritionally balanced diet, increase consumption of foods or supplements that contain antioxidants, and seek periodic optometric retinal examinations.

  1. Prevent Blindness America. Vision problems in the U.S. Schaumburg, IL: Prevent Blindness America 1994.
  2. Cavallerano AA, Cummings JP, Freeman, PB, et al. Optometric Clinical Practice Guideline on Care of the Patient With Age-Related Macular Degeneration. St. Louis: American Optometric Association, 1994.
  3. Van Der Hagen AM, Yolton DR, Karninski MS, Yolton RL. Free Radicals and Antioxidant Supplementation: A Review of Their Roles in Age-Related Macular Degeneration. J Am Optom Assoc 1993; 64:871-878.
  4. Hayes KC. Retinal Degeneration in Monkeys Induced by Deficiencies of Vitamin E or A. Invest Ophthalmol 1974; 13:499-510.
  5. Ham WT, Mueller Ha, Ruffolo JJ et al. Basic Mechanisms Underlying the Production of Photochemical Lesions in the Mammalial Retina. Curr Eye Res. 1984; 3:165-174.
  6. Organisciak DT, Wang HM, Li Z, Tso MO. The Protective Effect of Ascorbate in Retinal Light Damage of Rats. Invest Ophthalmol 1985; 26:1580-1588.
  7. 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.
  8. Age-Related Macular Degeneration Study Group. Multicenter Ophthalmic and Nutritional Age-Related Macular Degeneration Study-part 1; design, subjects and procedures. J aM Optom Assoc 1996; 67:12-29.
  9. Age-Related Macular Degeneration Study Group. Multicenter Ophthalmic and Nutritional Age-Related Macular Degeneration Study-part 2; antioxidant intervention and conclusions. J aM Optom Assoc 1996; 67:30-49.
  10. The Eye Disease Case-Control Study Group, Antioxidant Status and Neovascular Age-Related Macular Degeneration. Arch Ophthalmol 1993; 111:104-109.
  11. 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.

Vitamin C

Vitamin C (ascorbic acid) is an antioxidant found in fruits and vegetables. Scientific evidence suggests vitamin C lowers the risk of developing cataracts. Also, when taken in combination with other essential nutrients, it can slow the progression of age-related macular degeneration and visual acuity loss.

Vitamin C (ascorbic acid) is an antioxidant found in fruits and vegetables.

Scientific evidence suggests vitamin C lowers the risk of developing cataracts. Risk factors for cataracts include smoking, diabetes and steroid use, which deplete the eye’s lens of vitamin C.

Also, when taken with other essential nutrients, vitamin C can slow the progression of age-related macular degeneration (AMD) and visual acuity loss. AMD is the leading cause of blindness in people over age 55 in the Western world. The number of people with AMD is expected to triple by 2025.

Vitamin C’s benefits to eye health

Vitamin C helps promote healthy capillaries, gums, teeth, cartilage and the absorption of iron. Almost all cells of the body depend on it, including those of the eye, where it is concentrated in all tissues. Vitamin C also supports the health of blood vessels in the eye.

Our bodies do not create all of the vitamin C we need. This is why daily intake of vitamin C through diet, nutritional supplements, or fortified foods and beverages is important for maintaining good eye health.

Vitamin C and cataracts

Numerous studies have linked vitamin C intake and decreased risk of cataracts. In one study, women taking vitamin C for 10 years or more experienced a 64 percent reduction in the risk of developing nuclear cataracts. Researchers estimate that by delaying the onset of cataracts for 10 years, half of the cataract-related surgeries could be averted.

Other research showed that women taking a daily supplement with a dosage of 364 mg experienced a 57 percent reduction in their risk of certain types of cataracts.

Taking a supplement with at least 300 mg/day of vitamin C appears to help prevent cataract development.

Vitamin C and AMD

The landmark Age-Related Eye Disease Study (AREDS), sponsored by the National Eye Institute, linked AMD and nutrition. The study showed that people at high risk for the disease who took 500 mg/day of vitamin C, along with beta-carotene, vitamin E and zinc supplementation, slowed the progression of advanced AMD by about 25 percent and visual acuity loss by 19 percent. Other studies have confirmed these results.

Vitamin C daily intake*

Discover great recipes rich in Vitamin C. The U.S. Food and Drug Administration (FDA) recommends that men get 90 mg/day of vitamin C and women get 75 mg/day.

However, people under stress need more vitamin C than the recommended daily allowance. These groups include smokers, alcoholics, diabetics, pregnant or breastfeeding women, older adults, athletes, and people with chronic diseases who experience environmental stress from heat, cold or radiation. There is little scientifically documented risk in taking higher doses of vitamin C, except for diarrhea.

Food sources for vitamin C

Vitamin C is found almost exclusively in fruits and vegetables, including citrus fruits such as oranges, lemons, grapefruit, and limes. The table above lists foods known to be high in vitamin C. Also, the USDA Nutrient Database offers comprehensive nutritional information on more than 8,000 raw and prepared foods.

If you are not getting enough vitamin C through diet alone, consider adding a vitamin C supplement to your daily routine. However, always consult with a health care professional before taking supplements.

References

*At this time, the AOA is unaware of any studies that have examined interactions between medications and vitamin C. The AOA also is not aware of any adverse health reports from interactions between medications and vitamin C. However, the AOA recommends consulting with a health care professional before taking any supplement.

Vitamin D: The hot new vitamin

By Elizabeth Somer, Registered Dietician and
Author of Age Proof Your Body

Until recently, vitamin D was thought to play a primary role in preventing bone loss associated with diseases like osteoporosis and rickets. Research now indicates this vitamin is essential for a whole lot more than the health of our bones and can even help guard your eyesight.

We know that vitamin D is critical for the absorption of calcium and that it ensures the mineral gets deposited into bones. Emerging research has shown that vitamin D may protect against the onset of age-related macular degeneration (AMD), a leading cause of blindness in adults. In a recent study of nearly 8,000 participants, those with early AMD had lower blood levels of vitamin D.

Vitamin D is called the “sunshine vitamin” because our bodies can make it when exposed to sunshine. However, four very important factors affect the body’s ability to make vitamin D:

  1. Age: As we age, our bodies tend to make less vitamin D as exposure to the sun decreases. Therefore, dietary sources become increasingly important.
  2. Location: If you live above an imaginary line drawn between Los Angeles and Atlanta, you typically do not receive enough sun exposure year-round to guarantee optimal vitamin D levels.
  3. Skin color: Melanin is the pigment that gives skin its color. Greater amounts of melanin result in darker skin. The high melanin content in darker skin reduces the skin’s ability to produce vitamin D from sunlight. Some studies suggest that older adults, especially women, in these groups are at high risk of vitamin D deficiency.
  4. Sunscreen: Sunscreen blocks harmful UV rays that cause skin cancer, which is a good thing. But, sunscreen also blocks the skin’s ability to make vitamin D. People who lavishly use sunscreen can develop a deficiency, even if they are out in the sun. (And as the weather warms up and you spend more time outside, don’t forget to protect your eyes from UV light. Wear protective sunglasses and a hat the shields your face from direct sunlight.)

Due to work and lifestyle changes over recent years, the decrease in UV exposure has led to an increase in vitamin D deficiency and because of this, it’s important not only for eyesight but for overall health to include foods rich in vitamin D in your diet.

Fatty fish, like salmon and mackerel, are natural sources of vitamin D. The U.S. Food and Drug Administration allows only a few foods to be fortified with vitamin D, including milk, fortified orange juice, soymilk, and cereals. Most yogurts and other dairy products are not good vitamin D sources. To meet the minimum 400IU to 600IU daily recommendation for vitamin D, you must drink four to six glasses of milk. Your best bet is to include a few fortified foods on the daily menu and take a supplement that contains at least 400IUs of this vitamin.

For more information on vitamin D and eyesight, click here.

Emerging Research Vitamin D: Vitamin D Deficiency Has Been Linked to Age-Related Macular Degeneration, As Well as 17 Types of Cancer. 

Vitamin D is good for our bones and teeth. It aids in preventing rickets, cavities, and adult softening of the bones. Yet today there is significant evidence that vitamin D also plays a role in helping to prevent cancer, heart disease, diabetes, and AMD. Activated Vitamin D, also known as calciferol, is a fat-soluble essential vitamin that helps to prevent skeletal diseases by maintaining normal levels of calcium and phosphorous in the blood. Vitamin D also regulates cells, systems, and organs throughout the body. It is the most potent steroid hormone in the human body and is the only vitamin formed with the help of sunlight.

When ultraviolet B radiation is absorbed by the skin, it triggers the synthesis of vitamin D, which is stored in the liver. Before the Industrial Revolution, more than 90 percent of people living in Europe and North America obtained their supply of vitamin D from this sunlight-driven process. With work and lifestyle changes over the last 100 years, the decrease in UV exposure has led to an increase in vitamin D deficiency. Today, vitamin D deficiency has been linked to 17 types of cancer, cardiovascular disease, diabetes, autism, multiple sclerosis, schizophrenia, and even influenza. ( 1,2,3,4)

You are vulnerable to the lack of sunlight if you live in a northern climate, have black or dark brown skin, work indoors, or are housebound and elderly. Infants also are considered vulnerable. Therefore, it appears that the degree of UV B sunlight exposure you receive based on the latitude in which you live, your race, and working environment (office vs. outdoor worker), can greatly affect your health.

Vitamin D benefits to eye and systemic health

Age-Related Macular Degeneration 

A recent study presents evidence that vitamin D may protect against the onset of age-related macular degeneration (AMD). In a study of nearly 8,000 participants, those with early AMD were associated with lower blood levels of vitamin D. However, it must be noted that the authors caution additional studies are needed to confirm these findings. (5)

Vitamin D and cardiovascular disease

Cardiovascular disease (CVD) is associated with many eye diseases, including AMD and glaucoma. The etiology of cardiovascular disease is not completely understood. Yet, a recent review summarizes data supporting the hypothesis that insufficient levels of vitamin D may contribute to the worldwide high prevalence of CVD. (Zittermann A, Schleithoff SS, Koerfer R, Putting cardiovascular disease and vitamin D insufficiency into perspective, Br J Nutr. 2005 Oct;94(4):483-92 )

Juvenile diabetes

The American Academy of Pediatrics (AAP) announced in October 2008 it has doubled the recommended amount of vitamin D for infants, children, and adolescents. The decision to increase daily dosage is an update of the 2003 AAP initiative that sought to combat childhood rickets, but clear evidence suggests a correlation of juvenile diabetes and latitude, with children in Finland having nearly 400 times the rate of juvenile diabetes compared with children living near the equator.

Obesity, diabetes, and the metabolic syndrome

Vitamin D deficiency is important to pre-diabetic and diabetic adults, as it lowers insulin resistance, or the ability of cells to utilize excess glucose from the bloodstream. As well, vitamin D acts as an immunosuppressant and improves pancreatic function.

Food sources and supplementation

There is no substitute for the sunlight-driven process of vitamin D synthesis. As a point of reference, approximately 10,000 IU of vitamin D3 is produced by one hour of midday summer full-body skin exposure for Caucasians living at southern latitudes. Season, latitude, time of day, cloud cover, smog, and applied sunscreen all affect UV B exposure. Sunscreen with a protection factor of 8 or higher blocks vitamin D synthesis.

It is possible to supplement the diet with biologically inactive vitamin D found in plants and marine life. Vitamin D3 is abundant in cold-water fish (i.e. red sockeye salmon, sardines or cod liver oil) along with crucial essential fatty acids. Even less vitamin D (100 IU vitamin D2 per cup) is available from the synthetic source, ergocalciferol, used to fortify milk. The most recent 2005 U.S. Department of Agriculture (USDA) Food Triangle recommends the equivalent of three 8 oz. glasses of milk each day. However, 24 ounces of vitamin D fortified milk supplies only a meager 300 IU of the less potent plant-based and synthetic vitamin D2. There is a growing consensus that milk sources are not enough to maintain overall health for Caucasians, let alone African-Americans and populations living further from the equator. (6)

Vitamin D daily intake*

One cup of milk has 100 IU of vitamin D2, which has 70 percent of the effectiveness of natural vitamin D3 found in fish.

The USDA Recommended Daily Allowance of vitamin D, regardless of race, season or geographic location, presently is:

Less than age 50200 IU
Age 50400 IU
50 – 70
70+800 IU


References

*At this time, the AOA is unaware of any studies that have examined interactions between specific medications and vitamin D. The AOA also is not aware of any adverse health reports from interactions between specific medications and vitamin D. However, the AOA recommends consulting with a health care professional before beginning any supplementation regiment.

Vitamin E

Vitamin E is a powerful antioxidant found in nuts, fortified cereals, and sweet potatoes. Research indicates it protects cells in the eyes from unstable molecules called free radicals, which break down healthy tissue.

Research has shown that vitamin E, found in nuts, fortified cereals, and sweet potatoes, can protect cells of the eyes from damage. This damage is caused by unstable molecules called free radicals, which break down healthy eye tissue. When this happens, the risks for age-related macular degeneration (AMD) and cataract formation increase.

Worldwide, more than 25 million people are affected by AMD. In the Western world, AMD is the leading cause of blindness in people over age 55. The number of people with AMD is expected to triple by 2025 as the population ages.

Vitamin E’s benefits to eye health

Studies indicate that vitamin E reduces the progression of AMD and cataract formation. Vitamin E also plays a significant role in the immune system, the health of cell membranes, DNA repair, and other metabolic processes.

The human body does not create the vitamin E it needs. This is why the daily intake of vitamin E through your diet or nutritional supplements is important for good eye health.

Vitamin E and cataracts

Studies have indicated adding vitamin E to the diet can delay cataract formation. A recent study demonstrated that higher dietary intakes of lutein and zeaxanthin along with vitamin E significantly decreased the risk of cataracts.

Vitamin E and AMD

The landmark Age-Related Eye Disease Study (or AREDS), sponsored by the National Eye Institute, established that AMD is linked to nutrition. The study showed that a 400 IU/day intake of vitamin E, taken with beta-carotene, vitamin C and zinc supplementation, slows the progression of AMD by about 25 percent in individuals at high risk for the disease. Seven smaller studies have confirmed these results.

Vitamin E daily intake*

The USDA Nutrient Database offers comprehensive information on raw and prepared foods. The U.S. Food and Drug Administration recommends that both men and women get 22 IU of vitamin E per day. Diets low in fat can significantly decrease vitamin E intake. In adults, symptoms of vitamin E deficiency include nerve damage, muscle weakness, poor coordination, involuntary movement of the eyes and breaking of red blood cells leading to anemia. Vitamin E is a fat-soluble supplement that should not be taken in excess by anyone taking supplements or medications that have blood-thinning qualities. Always consult with a health care professional before beginning a supplementation regimen.

Food sources that contain vitamin E

Most Western diets are low in vitamin E, which can be found in nuts, vegetable oils, peanut butter, fortified cereals, and sweet potatoes. The table below lists foods high in vitamin E antioxidants.

References 

*At this time, the AOA is unaware of any studies that have examined interactions between specific medications and vitamin E. The AOA also is not aware of any adverse health reports from interactions between specific medications and vitamin E. However, the AOA recommends consulting with a health care professional before taking any supplement.

Essential fatty acids

Fats are a necessary part of the human diet. They maintain the integrity of the nervous system, fuel cells and boost the immune system. Research shows omega-3 fatty acids are important for proper visual development and retinal function.

Omega-3: DHA and EPA

Dietary fat is an important source of energy and a necessary part of the human diet. Fatty acids, a component of fat molecules, are important in keeping our eyes healthy.

Two families of essential fatty acids exist in nature: omega-3 and omega-6. These essential fatty acids help support the cardiovascular, reproductive, immune and nervous systems. They also help the brain develop and the sensory systems mature.

Research has shown that two omega-3 fatty acids—docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)—are important for proper visual development and retinal function.

DHA and EPA Omega-3 Fatty Acids and Eye Health

DHA is found in the highest concentration in the retina, suggesting it has an important function there. EPA is used in the production of DHA in the body.

Studies in pre-term and full-term infants suggest that getting enough omega-3 fatty acids in the diet is essential for optimal visual development. A number of studies have shown that animals that do not get enough DHA in their diets suffer visual impairment and degradation of the retina.

Dry eye syndrome also has been linked to omega-3 deficiency. Additionally, low levels of DHA and EPA have been associated with diabetic retinopathy, age-related macular degeneration (AMD) and retinopathy of prematurity.

Essential fatty acid daily intake*

The typical American diet includes 1.6 grams per day of omega-3 fatty acids. EPA and DHA usually comprise 6 percent to 12 percent of this value (0.1-0.2 grams per day). This level is well below the American Heart Association’s recommended 0.5-1.0 grams per day of EPA + DHA. According to the U.S. Food and Drug Administration, consuming up to 3 grams per day of DHA and EPA is generally considered safe.

Food sources that contain essential fatty acids

EPA and DHA are concentrated in fatty fish and other seafood. In addition, you can take omega-3 fatty acid supplements in oil or capsule form.

For individuals who choose not to consume fish, vegetarian DHA is commercially manufactured from microalgae.

Animals can convert very small amounts of DHA through the consumption of α-linolenic acid, an omega-3 fatty acid found in plants, animals, and milk.

References

*At this time, the AOA is unaware of any studies that have examined interactions between specific medications and essential fatty acids. The AOA also is not aware of any adverse health reports from interactions between specific medications and essential fatty acids. However, the AOA recommends consulting with a health care professional before taking any supplement.

Lutein & Zeaxanthin

Lutein and zeaxanthin are important nutrients found in green leafy vegetables, as well as other foods, such as eggs. Many studies show that lutein and zeaxanthin reduce the risk of chronic eye diseases, including age-related macular degeneration and cataracts.

Cataracts and age-related macular degeneration (AMD) are the leading causes of visual impairment and acquired blindness in the U.S, affecting millions of aging Americans. Nutrition is one promising way to prevent or delay the progression of these diseases.

Two carotenoids, lutein (pronounced loo-teen) and zeaxanthin (pronounced zee-uh-zan-thin), are antioxidants that are located in the eye. (Insert – Several dark) green leafy vegetables, as well as other foods such as eggs, contain these important nutrients. Many studies have shown that lutein and zeaxanthin reduce the risk of chronic eye diseases, including AMD and cataracts.

Lutein’s & zeaxanthin’s benefits to eye health

Lutein and zeaxanthin filter harmful high-energy blue wavelengths of light and help protect and maintain healthy cells in the eyes. Of the 600 carotenoids found in nature, only these two are deposited in high quantities in the retina (macula) of the eye.

The amount of lutein and zeaxanthin in the macular region of the retina is measured as macular pigment optical density (MPOD). Recently, MPOD has become a useful biomarker for predicting disease and visual function.

Unfortunately, the human body does not naturally make the lutein and zeaxanthin it needs. This is why eating green vegetables is important. Getting daily amounts of lutein and zeaxanthin through your diet or nutritional supplements can help maintain good eye health. (Insert – Like many other naturally occurring nutrients, the way the vegetables are prepared/consumed and the items that they are consumed with can affect how well the body can absorb them. As such sometimes additional supplements may be needed for optimal therapy.)

Lutein, zeaxanthin and cataracts

The crystalline lens (the natural lens in the eye) primarily collects and focuses light on the retina. To do this throughout your life, the lens must remain clear. Oxidation of the lens is a major cause of cataracts, which cloud the lens.

Antioxidant nutrients neutralize free radicals (unstable molecules) that are associated with oxidative stress and retinal damage. This is why the antioxidants lutein and zeaxanthin likely play a role in preventing cataracts. In fact, a recent study demonstrated that higher dietary intake of lutein and zeaxanthin and vitamin E was associated with a significantly decreased risk of cataract formation.

Research—lutein and zeaxanthin and cataracts

Lutein and zeaxanthin intake and its relationship to risk of cataracts have been examined in four recent observational or epidemiological studies:

  • The Nurses’ Health Study found that consuming high amounts of lutein+zeaxanthin reduced the need for cataract surgery. Intake among this group was approximately 6 mg per day.
  • The Health Professional’s Follow-Up Study also found that high amounts of lutein+zeaxanthin (6.9 mg per day) lowered the need for cataract surgery.
  • The five-year follow-up to the Beaver Dam Eye Study showed that people who got the most lutein+zeaxanthin had a much lower risk for developing new cataracts than people had the least amounts.
  • A study of 372 men and women aged 66-75 in England found that the risk for a specific type of cataracts was the lowest in people with the highest amount of lutein in their blood.

Lutein, zeaxanthin and AMD

There is a lot of evidence that lutein and zeaxanthin reduce the risk of AMD. In fact, in the Age-Related Eye Disease Studies (AREDS and AREDS2), the National Eye Institute found that taking certain nutritional supplements every day reduces the risk of developing late AMD. Beyond reducing the risk of eye disease, separate studies have shown that lutein and zeaxanthin improve visual performance in AMD patients, cataract patients and people in good health.

Research

One of the first large studies on carotenoids is the Eye Disease Case-Control Study, in which diet was compared to the risk for developing AMD. Results found a significantly lower risk of developing eye disease in people with high amounts of lutein+zeaxanthin in their blood. Also, those people eating a diet with the most lutein+zeaxanthin (as much as 5.8 milligrams (mg) per day) had a significantly lower risk for AMD than those whose diet contained the least amount (as low as 1.2 mg per day). Dietary studies confirmed the association between frequent consumption of spinach or collard greens, particularly good sources of lutein and zeaxanthin, and lower AMD risk.

Similar results were found in a recent analysis of a national dietary study called the Third National Health and Nutrition Examination Survey or NHANES III. This analysis also showed that consuming 6 mg per day of lutein+zeaxanthin was associated with reduced risk for developing AMD.

Lutein & zeaxanthin daily intake*

Discover great recipes rich in Lutein

The USDA Nutrient Database offers comprehensive information on raw and prepared foods.

If you are not getting enough lutein and zeaxanthin through your diet alone, consider taking daily supplements. Although there is no recommended daily intake for lutein and zeaxanthin, most recent studies show health benefits in taking 10 mg/day of a lutein supplement and 2 mg/day of a zeaxanthin supplement.

Lutein and zeaxanthin are found together in many food sources. Dark green leafy vegetables are the primary source of lutein and zeaxanthin, but they are also present in lesser amounts in other colorful fruits and vegetables, such as broccoli, orange peppers, corn, peas, persimmons and tangerines.

Good food sources of lutein and zeaxanthin (mg/serving)

Food/serving
(1 cup)
Lutein and
Zeaxanthin
LuteinZeaxanthin
Kale20.5 – 26.5*1.1 – 2.2*
Collard greens15.35.1
Spinach3.6 – 12.6*1.7 – 13.3*0.5 – 5.9*
Turnip greens12.10.4
Broccoli2.1 – 3.5*1.4 – 1.6*
Corn, yellow1.4 – 3.00.60.9
Peas, green2.32.2
Orange pepper1.7
Persimmons1.40.8
Tangerine0.50.2

*depending on variety and preparation

Sources: USDA-NCC Carotenoid Database, 1998, USDA Food Nutrient Database for Standard Release 13
Hart and Scott, 1995, HHN-1550B/0502

What you need to know about lutein & zeaxanthin and eye health

Given the positive association between lutein and zeaxanthin and age-related eye disease, it seems prudent for people to obtain higher amounts of these nutrients from their daily diet.

Eating five servings of fruits and vegetables each day, as currently recommended by the National Cancer Institute and U.S. Department of Agriculture, can provide about 5 to 6 mg of carotenoids, including lutein and zeaxanthin, given wise choices of fruits and vegetables (see table for good food sources of these nutrients).

However, most people in the U.S. are not eating five servings of fruits and vegetables each day. The average intake of lutein and zeaxanthin is approximately 2 mg per day. The studies referenced here suggest an intake of 6 mg or more per day to decrease the risk of developing AMD and cataracts. If you find it difficult to increase the amount of these carotenoids in your diet, multivitamin/mineral and eye health supplements containing lutein and zeaxanthin are available.

References 

*At this time, the AOA is unaware of any studies that have examined interactions between medications and lutein and zeaxanthin. The AOA also is not aware of any adverse health reports from interactions between medications and lutein and zeaxanthin. However, the AOA recommends consulting with a health care professional before beginning any supplementation regiment.

Zinc

Zinc is an essential trace mineral or “helper molecule.” It plays a vital role in bringing vitamin A from the liver to the retina in order to produce melanin, a protective pigment in the eyes. Zinc is highly concentrated in the eye, mostly in the retina and choroid, the vascular tissue layer lying under the retina.

Impaired vision, such as poor night vision and cloudy cataracts, has been linked to zinc deficiency. A person with too little zinc in their body is also at risk for alopecia (loss of hair from eyebrows and eyelashes), mental sluggishness and increased susceptibility to infection.

Zinc’s benefits to eye health

People at high risk for age-related macular degeneration (AMD), or who are already experiencing the early stages of AMD, may benefit from increased zinc intake. The human body does not produce the zinc it needs, so daily intake of zinc through diet, nutritional supplements, or fortified foods and beverages is important for the maintenance of good eye health. Red meat, seafood, poultry, eggs, wheat germ, mixed nuts, black-eyed peas, tofu, and beans contain zinc.

Zinc and AMD

The landmark Age-Related Eye Disease Study (AREDS), sponsored by the National Eye Institute, established that AMD is linked to nutrition. The study showed that individuals at high risk for AMD could slow the progression of advanced AMD by about 25 percent and visual acuity loss by 19 percent by taking 40-80 mg/day of zinc, along with certain antioxidants. Taking higher levels of zinc may interfere with copper absorption, which is why the AREDS study also included a copper supplement.

However, high doses of zinc may upset the stomach. Therefore, a follow-up study, AREDS2, which is currently in progress, is testing a more moderate dose of 25 mg/day.

Zinc daily intake*

The U.S. Food and Drug Administration (FDA) recommends 11 mg/day of zinc for men and 8 mg/day for women.

For those at high risk for AMD, the AREDS study showed that higher levels of zinc (40-80 mg/day) is beneficial. Zinc supplementation has been known to interfere with copper absorption, so it is strongly recommended that people taking zinc also take 2 mg/day of copper.

Food sources that contain zinc

The table above highlights good sources of zinc, which include red meat, seafood, poultry, eggs, wheat germ, mixed nuts, black-eyed peas, tofu, and beans.

Discover great recipes rich in zinc.

References

*At this time, the AOA is unaware of any studies that have examined interactions between specific medications and zinc. The AOA also is not aware of any adverse health reports from interactions between specific medications and zinc. However, the AOA recommends consulting with a health care professional before taking any supplements.

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