Overdosing on eye supplements like lutein, omega-3 can harm vision: expert

Ophthalmologists are warning that prolonged, high-dose consumption of popular eye health supplements, such as lutein and omega-3 fatty acids, could paradoxically lead to vision impairment. Dr. Won Yeo-kyung, an ophthalmologist with a large YouTube following, cautioned against the misconception that higher doses equate to better results. She noted that in clinical practice, patients sometimes experience adverse effects from extended use of high-potency supplements. A key concern involves supplements formulated for macular degeneration prevention, which often contain high levels of zinc. Dr. Won explained that excessive zinc absorption over time can block the body's uptake of copper, a vital nutrient. Copper deficiency can affect nerve function, including the optic nerve connecting the eye and brain, potentially leading to vision disturbances or even decreased eyesight in rare cases. Omega-3 fatty acids also require careful consideration. Individuals taking anticoagulant medications like aspirin for cardiovascular conditions should consult a healthcare professional before taking high-dose omega-3s, as it can increase bleeding risks. The effectiveness of lutein is also often misunderstood. While lutein, a pigment in the macula, helps filter blue light and protects the retina from oxidative stress, it is not a cure for age-related presbyopia or cataracts. Dr. Won clarified that blurred near vision due to presbyopia, a physical change in the lens's elasticity and focusing muscles, cannot be corrected by lutein intake. Lutein acts on the retina, not the lens, and therefore cannot clear cloudy cataracts or restore focus. Furthermore, the retina has a limit to how much lutein it can absorb. Reports exist of excess lutein accumulating in the macula as yellow crystals when intake exceeds the body's capacity, as it is not efficiently excreted. The commonly cited 4:1 ratio of lutein to zeaxanthin is based on average blood levels and may not suit everyone, as individual retinal conditions vary. Overconsumption can also burden the liver and kidneys. Dr. Won also highlighted early warning signs of retinal diseases, such as straight lines appearing wavy, which could indicate retinal swelling or structural changes. She advised prompt consultation with an ophthalmologist if such distortions are noticed, especially when checked with one eye at a time. Even normal vision test results may not reveal underlying issues, as the brain can compensate for peripheral vision loss. She recommended optical coherence tomography (OCT) scans for a more detailed view of retinal layers, which can detect hidden problems early.

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Taking high-dose supplements for a long time can cause side effects like vision loss.