Niacin, also known as vitamin B3, is a vitamin that people sometimes take to lower their cholesterol or manage high levels of fat in the blood.
While niacin can be helpful when used correctly, taking too much of it can be dangerous. In fact, it can even damage your eyes.
A recent report from the New York Eye and Ear Infirmary of Mount Sinai tells the story of a man who nearly lost his eyesight after taking large amounts of niacin without a doctor’s guidance.
This case involved a 61-year-old man who started having blurry vision that got worse over the course of a month.
By the time he went to the hospital, his vision had become so poor that he was almost legally blind. In one eye, he could only see at 20/150, and in the other, 20/100. That means he could barely read the biggest letters on an eye chart.
At first, he only told doctors that he had high blood pressure and high cholesterol. He didn’t mention anything about taking supplements.
Later, he admitted that he had been taking between 3 and 6 grams of niacin every day for several months. He said he started taking it to lower his risk of heart disease, but he didn’t know it could hurt his eyes.
Doctors explained that the usual recommended dose of niacin for cholesterol problems is between 1 and 3 grams a day. A 6-gram dose is the absolute upper limit and should only be taken under close medical care. The man had been buying niacin over the counter and using it on his own, which turned out to be very risky.
Using special eye scans, doctors discovered that he had a rare condition called niacin-induced cystoid maculopathy. This condition causes swelling in the macula, the part of the eye that helps you see clearly and in detail. The high amount of niacin had caused fluid to build up in his retina, making his vision blurry.
Luckily, the doctors caught the problem early. They told him to stop taking niacin right away. Just one week later, his vision started to improve. Two months later, all the swelling was gone, and his eyesight returned to normal—20/20.
This case is a strong reminder that just because vitamins are sold without a prescription doesn’t mean they are always safe. Taking large amounts of vitamins or supplements without a doctor’s advice can lead to serious health problems, including eye damage.
If you are thinking about taking high-dose supplements, always talk to a doctor first. Some vitamins can cause harm when taken in large amounts. And if you notice sudden changes in your vision, seek medical help as soon as possible.
The study was led by Dr. Richard Rosen and published in the Journal of VitreoRetinal Diseases. It shows how important it is to use supplements responsibly and with proper medical guidance.
If you care about nutrition, please read studies about the best time to take vitamins to prevent heart disease, and vitamin D supplements strongly reduce cancer death.
For more information about nutrition, please see recent studies about plant nutrient that could help reduce high blood pressure, and these antioxidants could help reduce dementia risk.
