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Declining vision affects over 400 million people worldwide and decreases the quality of life. Nutrition, along with targeted ocular treatment, may help offset declining vision. This blog will review some of the latest scientific research on ocular disease and discuss how an anti-inflammatory diet rich in omega-3 fatty acids and carotenoids, along with targeted supplementation, can support eye health.

Ocular Disease

Age-related macular degeneration (AMD) is the leading source of visual deterioration in adults. Several other ocular conditions can also cause visual impairment and decrease quality of life. There are several risk factors associated with ocular degeneration and disease. For example, age, genetic polymorphisms, family history, increased BMI, and smoking are all risk factors for AMD.

On the other hand, physical activity and dietary patterns, such as the Mediterranean diet, may be protective and decrease the risk of AMD progression. The Mediterranean diet is rich in plant-based foods such as fruits and vegetables, as well as fish. This dietary pattern supplies the body with carotenoids, omega-3 fatty acids, and other nutrients to help keep the eyes functioning properly. Since ocular degeneration is influenced by inflammation, a consistent intake of these supportive compounds can be part of a therapeutic strategy to preserve eye health as we age.

The Role of Inflammation

Inflammation is an important consideration regarding the development and progression of ocular diseases such as AMD and glaucoma. As we age, we can experience dysfunction in the mitochondria or energy centers of the cell. This change results in decreased energy production. The retina has a high metabolic demand and requires a large amount of oxygen to function correctly. In addition to mitochondrial dysfunction, this demand also puts the eyes at risk for increased levels of oxidative stress.

Dysbiosis, an imbalance in the microbiome, is related to certain ocular diseases. A systematic review of visual inflammatory disorders found that bacterial species that produce short-chain fatty acids are lower in people with particular conditions. Patients with Sjogren’s syndrome, an autoimmune disease that can cause dry eyes, often have altered microbiome profiles compared to healthy individuals.

Vitamin D, a nutrient known for its anti-inflammatory effects, plays a role in eye health by protecting the eyes against oxidative damage. It also promotes epithelial barrier integrity of the cornea. Vitamin D status is associated with sight-threatening diabetic retinopathy and myopia. Research suggests that vitamin D genetic polymorphisms can affect disease risk for conditions like myopia, uveitis, and AMD.

Other compounds, such as omega-3 fatty acids and carotenoids, are also needed for vibrant eye health. Researchers looked at food frequency questionnaires from the Age-Related Eye Disease Studies. They found that nutrients such as magnesium, vitamin A, vitamin C, beta-carotene, lutein, and zeaxanthin were associated with a decreased risk of AMD. In contrast, saturated fatty acid, monounsaturated fatty acids, and oleic acid were associated with an increased risk. This study also found that genetic polymorphisms influenced the beneficial effect of omega-3 fatty acids for specific individuals.

Antioxidants

The macula of the retina helps provide sharp color vision. The macular contains lutein, zeaxanthin, and meso-zeaxanthin. These carotenoids protect the retina against blue light and reactive oxygen species. People with AMD tend to have lower macular pigment optical density (MPOD). MPOD can serve as a marker to assess the risk of visual dysfunction. Dietary antioxidants can help modulate the function of macular pigment while supporting mitochondrial function and decreasing inflammation.

Humans must obtain carotenoids, such as lutein and zeaxanthin, through the diet as they cannot be synthesized endogenously. Diet is considered a clinical strategy to prevent or delay the progression of age-related macular degeneration. However, improvements are not immediate, and people benefit most from a consistent intake of carotenoid-rich foods or supplementation over time. One systematic review and meta-analysis found that MPOD increased after three months of high-dose lutein and zeaxanthin supplementation (5 mg/day). Since American adults have been found to consume an estimated 1-2 mg daily from food, supplementation may be beneficial to see a clinical effect.

In one study, healthy participants were given carrot juice, spinach powder, carotenoid supplements, or a placebo. There was an association between serum levels of lutein and zeaxanthin and macular pigment level in the groups receiving the supplement or the dietary sources of carotenoids. However, after eight weeks, the changes in macular pigment level and markers of inflammation were statistically insignificant. Participants who initially had lower macular pigment levels saw more of an improvement.

Avocados are a dietary source of lutein. In a six-month randomized, controlled trial, healthy participants were given one avocado, one potato, or one cup of chickpeas daily. Serum lutein increased by 25%, and macular pigment density also increased in the avocado group. Besides being rich in lutein, avocados increase HDL cholesterol, which transports lutein in plasma.

The Age-Related Eye Disease Study found that participants who used daily supplementation of antioxidants (vitamins C and E along with beta-carotene) and zinc experienced a significant reduction in AMD. After five years, the estimated probability of AMD progression was 20% for the antioxidants and zinc group, compared to 28% for the placebo group. Those who only consumed the antioxidant supplement had a 23% probability, while those in the zinc-only group had a 22% probability of disease progression.

A study on AMD used a product formulated using nutrients from the second Age-Related Eye Disease Study and compared the benefits of combining it with zinc or additional meso-zeaxanthin. After two years, both groups showed a statistically significant increase in macular pigment.

Yet another study compared the use of a carotenoid supplement with omega-3 fatty acids against the Age-Related Eye Disease Study 2 formulated product. The carotenoid supplement significantly improved contrast sensitivity function after six months. MPOD and visual acuity did not improve significantly in either group. The researchers postulated that the carotenoid plus omega-3 fatty acid supplement yielded better results due to improved absorption. Since carotenoids are lipid-soluble, pairing these compounds with omega-3 fatty acids increases bioavailability.

Lutein and zeaxanthin are beneficial for ocular conditions besides AMD as well. Older adults were given lutein and zeaxanthin supplementation for six months and experienced significant improvements in night vision. MPOD, glare recovery time, and valuable field of view also improved.

Omega-3 Fatty Acids

Numerous studies have looked at the beneficial effects of omega-3 fatty acids on healthy vision. Long-chain omega-3 fatty acids are abundant in the retina. The Limpia Study found that higher levels of plasma docosapentaenoic acid (DPA), a type of omega-3 fatty acid, were significantly associated with macular pigment optical density in people with AMD.

A diet rich in omega-3 fatty acids can help slow the decline of ocular conditions such as retinitis pigmentosa, which can cause night blindness and tunnel vision. Adults who were supplementing with vitamin A had a 40% slower decline in distance vision if they also had a high intake of omega-3 fatty acids.

Omega-3 fatty acids can help address dry eye syndrome. In response to dryness, increased inflammatory cytokines such as IL-6 and TNF-α are found in the eye. Omega-3 fatty acids not only exert anti-inflammatory properties but also play an essential role in the structure of cellular membranes and may even improve tear function.

Finally, one hundred healthy adults either received a lutein supplement or lutein plus the omega-3 fatty acid docosahexaenoic acid (DHA) for three months. MPOD was significantly higher in the DHA group compared to the lutein-only group. While the lutein group experienced a 29% increase in MPOD for both eyes, the lutein and DHA group had a 39.6% increase.

Closing Thoughts

• Inflammation and mitochondrial dysfunction are critical drivers of ocular disease. An anti-inflammatory diet rich in omega-3 fatty acids, carotenoids, and targeted supplementation can help reduce reactive oxygen species and support eye health.
• Incorporate dietary sources of omega-3 fatty acids into your diet by consuming wild-caught cold-water fish such as salmon, sardines, cod, and herring. If you are incorporating a fish oil supplement into your routine, ensure it is of good quality. Working with a qualified nutrition professional can be helpful in high-quality sourcing products.
• Plant-based sources of omega-3 fatty acids include foods such as chia, flaxseeds, and walnuts.
• Regularly consume dietary sources of carotenoids. Lutein and zeaxanthin can be found in dark leafy greens, such as spinach and kale, and foods such as cruciferous vegetables, corn, squash, avocado, and egg yolks. Since carotenoids are lipid-soluble, eating these foods with dietary fat can help increase their bioavailability. Lightly sauté vegetables in avocado oil or sprinkle extra virgin olive oil over raw or already-cooked vegetables.
• Consult with a qualified nutrition professional to determine if lutein and zeaxanthin supplementation is proper for you.

If you plan to make food or supplement changes, have food or supplement allergies, or have questions about which foods or supplements are best suited to your eye and vision needs, talk to your doctor, nutritionist, dietician, or another member of your healthcare team for personal options based on your circumstances.