Age-related eye diseases are the main cause of vision loss and blindness in the elderly. This includes age-related macular degeneration (AMD), cataracts, glaucoma, and diabetic retinopathy.
Some nutrients play important roles in eye health. Eye diseases are thought to be partially related to oxidative stress and damage. This has sparked interest in the potential role of antioxidants and other nutrients as supplements for eye health and the prevention of age-related eye diseases.
This article reviews key nutrients for eye health (including vitamins and minerals) and provides recommendations for those who may benefit from supplements.
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Vitamins and minerals for eye health
Risk factors for developing AMD include age, sun exposure, smoking, and nutritional deficiencies.
Because AMD is partially caused by oxidative stress, some theories suggest that antioxidants reduce cell damage in the retina (the tissue layer at the back of the eye).
Higher dietary intakes of beta-carotene, vitamin C, vitamin E, and zinc have been shown to reduce the risk of AMD in older adults by 35%. However, further research has found that antioxidant nutrients and supplements are not helpful in primary prevention of AMD.
Some data support the use of supplements to slow the progression of AMD. Most of the study data comes from the Age-Related Eye Disease Study (AREDS) conducted in the United States. As a result of this large randomized clinical trial, several publications provided data supporting nutrient supplementation in some cases.
The study protocol used an antioxidant formulation containing several nutrients. The original AREDS prescription provided:
A follow-up AREDS study added 10 mg lutein and 2 mg zeaxanthin or omega-3 fatty acids and removed beta-carotene.
In both studies, participants with moderate AMD in one or both eyes were less likely to progress to advanced AMD.
beta carotene
Beta-carotene is a source of vitamin A. It is one of the few provitamin A carotenoids derived from plant sources. Beta-carotene is converted to vitamin A in the body.
Good sources of dietary beta-carotene include:
- sweet potato
- spinach
- pumpkin
- carrot
- cantaloupe
- red bell pepper
The original AREDS study found that this formulation reduced the risk of patients with moderate AMD developing further advanced AMD by 25%. A follow-up study found that removing beta-carotene from the formulation did not change the study results.
Beta-carotene was removed because it is thought to increase the risk of developing lung cancer in smokers. In the follow-up AREDS study, the group that took beta-carotene was more likely to develop lung cancer. Most of these participants were former smokers.
However, increased dietary intake (but not from supplements) of vitamins containing beta-carotene was associated with a lower risk of progression to late-stage AMD.
Data suggests that increasing dietary intake of foods containing beta-carotene may be helpful. However, keep in mind that more is not always better. Evidence does not support the use of beta-carotene supplements to prevent worsening of AMD.
vitamin C
Vitamin C is a water-soluble vitamin with antioxidant properties.
Vitamin C is an essential nutrient. The body can’t make it on its own. It can only be obtained through food or supplements. Good sources of vitamin C are:
- green pepper
- orange
- orange juice
- kiwi
- broccoli
- strawberry
The formulation used in the AREDS study contained 500 mg of vitamin C.
The dose of vitamin C in the AREDS formulation exceeded the recommended dietary allowance (RDA), or amount sufficient to meet nutrient requirements. However, it did not exceed the tolerable upper limit, which is the maximum level of total intake that can be safely consumed.
Data regarding vitamin C for cataract prevention are mixed. The AREDS study did not find that vitamin C-containing preparations prevented or slowed cataract progression.
vitamin E
Vitamin E is a soluble vitamin found in some foods and can be added to foods or available in supplement form. Vitamin E comes in many forms, but only alpha-tocopherol is known to meet human requirements.
Vitamin E acts as an antioxidant and plays a role in immune function. Good sources of vitamin E include:
- Nuts (almonds, peanuts)
- Seeds (sunflower seeds)
- sunflower oil and safflower oil
- peanut butter
High dietary intake of vitamin E has been shown to reduce the risk of developing AMD by 20%. However, a randomized clinical trial comparing vitamin E supplementation with a placebo (a non-therapeutic drug) showed that vitamin E does not prevent AMD.
The AREDS study formulation contained 400 international units (IU), or 268 mg of alpha-tocopheryl. The amount of vitamin E in the AREDS formulation (400 IU) far exceeds the daily requirement of vitamin E. However, no adverse events were reported at this dose.
Men should talk to their health care provider about the dosage of vitamin E used in AREDS prescriptions. High doses of vitamin E are controversial because one study found that high doses of vitamin E increased the risk of prostate cancer.
However, the AREDS trial did not find that high doses of vitamin E increased the risk of prostate cancer. A recent meta-analysis concluded that vitamin E intake has no effect on prostate cancer risk.
Vitamin E can interact with some prescription medications, so it’s important to discuss all medications and supplements with your doctor.
zinc
Zinc is an essential mineral found in some foods and supplements.
Good sources of zinc include:
- oysters and crab
- fortified cereal
- beef
- pork
- turkey
The amount of zinc in the AREDS formulation is 80 mg, which exceeds the permissible upper limit for zinc. The AREDS2 study formulation had a reduced amount of zinc at 25 mg but had the same protective effect. The National Eye Institute still recommends 80 mg of zinc.
High doses of zinc reduce the amount of copper absorbed by the body. Since the amount of zinc in the AREDS formulation was high, copper was also added to the formulation.
omega 3
Omega-3 fatty acids are polyunsaturated fats. Common omega-3 fatty acids include alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA).
Good sources of omega-3 fatty acids in your diet include:
- Fish (salmon, herring)
- Seeds (flaxseed, chia seeds)
- nuts
Researchers hypothesize that omega-3 fatty acids may have some protective effect on the retina.
One study found that people who eat fatty fish at least once a week have a 53% lower risk of developing AMD.
A large study of women found that those with the highest dietary intakes of DHA and EPA had a 38% lower risk of developing AMD. The cohort of participants in the AREDS trial who reported higher intakes of omega-3 fatty acids were about 30% less likely to develop neovascular AMD.
In the AREDS2 study, the omega-3 fatty acids 350 mg DHA and 650 mg EPA were added to the formulation. The study results did not show that adding omega-3 fatty acids provided any additional benefits.
Another review concluded that supplementing AMD patients with omega-3 fatty acids does not reduce the risk of disease progression.
lutein and zeaxanthin
Lutein and zeaxanthin are both carotenoids related to beta-carotene and vitamin A. Both lutein and zeaxanthin are present in the human eye. These are the only two carotenoids present in the macula and lens.
Good sources of lutein and zeaxanthin in your diet include:
- kale
- spinach
- cabbage
- broccoli
- beans
- egg
- corn
In the AREDS2 study, 10 mg of lutein and 2 mg of zeaxanthin were added to the supplement formulation. They found that lutein and zeaxanthin are suitable replacements for beta-carotene.
A word from Berrywell
Your body needs fat to absorb lutein, zeaxanthin, beta-carotene, and vitamin A. Adding a drizzle of olive oil or sliced avocado to your kale salad not only adds flavor, but also helps absorb nutrients that help protect your eyes. health.
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Who should take eye health supplements?
Available evidence suggests that for people with moderate AMD in one or both eyes, supplementation with antioxidants (vitamins C, E, zinc) may slow the progression of AMD. Masu. This benefit appears to be greater in patients with intermediate-stage AMD than in early-stage AMD.
If you are a smoker or have a history of smoking, you should look for eye health formulations that do not contain beta-carotene. Beta-carotene has been found to increase the risk of developing lung cancer.
summary
Vitamins C and E, zinc, lutein, and zeaxanthin play important roles in eye health. Most healthy people can meet these nutrient requirements through diet alone. You can meet these requirements by eating a diet rich in fruits, vegetables, whole grains, and unsaturated fats.
Available evidence indicates that supplementation with these nutrients cannot prevent the development of AMD or cataracts, but may slow the progression of AMD. If you have moderate AMD in one or both eyes, taking supplements may reduce your risk of progressive AMD and vision loss.
Discuss nutritional supplementation with your doctor or registered dietitian (RD or RDN) and consider the risks and benefits of adding supplements.
