Niacin, also known as vitamin B3, is often used to help lower cholesterol and reduce high levels of fat in the blood. Doctors sometimes prescribe it for people who cannot tolerate other cholesterol medicines.
Because it is sold as a vitamin supplement, many people believe it is completely safe. However, taking very high doses without medical supervision can cause serious health problems, including damage to the eyes.
A recent report from the New York Eye and Ear Infirmary of Mount Sinai described a case that shows how dangerous self-prescribing supplements can be. The study focused on a 61-year-old man who developed severe blurred vision that gradually worsened over one month.
By the time he went to the hospital, his eyesight had declined so much that he was close to legal blindness. He could barely read even the largest letters on an eye chart.
At first, the man only told doctors about his history of high blood pressure and high cholesterol. He did not mention that he had been taking large amounts of niacin on his own.
Later, he explained that he had been taking between three and six grams of niacin every day for several months. He had purchased the supplement without a prescription, hoping it would lower his risk of heart disease.
Doctors explained that while niacin can be helpful in certain cases, the usual dose for managing cholesterol is between one and three grams per day, and even these amounts should be monitored by a healthcare provider. Six grams per day is considered extremely high and should never be taken without medical supervision.
Using special imaging equipment, doctors discovered that the man had developed a rare eye condition called niacin-induced cystoid maculopathy. This condition causes swelling in the macula, the part of the retina responsible for clear central vision. Excess niacin caused fluid to build up in his retina, leading to severe blurry vision.
Fortunately, the damage was reversible because doctors identified the cause in time. They immediately told him to stop taking niacin. Within one week, his vision began to improve. After two months, the swelling in his retina disappeared completely, and his eyesight returned to normal.
This case highlights an important message: just because a vitamin is sold over the counter does not mean it is harmless. High doses of supplements can act like powerful drugs and may cause serious side effects. Experts advise people to speak with a doctor before taking large amounts of any supplement, especially for medical conditions such as high cholesterol.
The study also reminds people to seek medical help right away if they notice sudden vision changes. Early treatment can prevent permanent damage. Responsible use of supplements and professional guidance are key to protecting both eye health and overall well-being.
If you care about eye health, please read studies about how vitamin B may help fight vision loss, and MIND diet may reduce risk of vision loss disease.
For more information about eye disease, please see recent studies about how to protect your eyes from glaucoma, and results showing this eye surgery may reduce dementia risk.
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