In the U.S., glaucoma is the leading cause of blindness, and primary open-angle glaucoma (POAG) is the most common type. Research performed at the New York Eye and Ear Infirmary of Mount Sinai (NYEE) suggests a low-carbohydrate diet may reduce the risk of developing POAG.*

Why a low-carbohydrate diet?

Low-carbohydrate diets have protective effects against neurologic disorders, such as Parkinson’s disease, Alzheimer’s disease, and epilepsy. The body normally uses carbohydrates, or glucose, as the main source for function in the brain. With a low-carbohydrate diet, the body may use compounds from the body’s breakdown of fat instead. Studies have shown this to improve function and slow down brain degeneration.

Similarly, researchers believe the low-carbohydrate diet may provide protective effects against POAG. POAG is caused by the degeneration of the optic nerve in the eye, which normally uses glucose as a source of energy to function.  

What they did 

Researchers followed data of 185,000 adult participants (between the ages of four and 75) from other studies collected between 1976 and 2017. Every two to four years, participants completed a food frequency questionnaire to assess their dietary intake. Participants would also notate if they had developed any health conditions, including POAG. 

For those that developed POAG, researchers divided them into groups based on their carbohydrate intake. Furthermore, participants who followed a low-carbohydrate diet were divided into three types of categories: 

• Participants on an animal-based low-carbohydrate diet
• Participants on a plant-based low-carbohydrate diet
• Participants on a low-carbohydrate diet with high fat and proteins, regardless of the source

After adjusting for multiple factors, including age, race, and body mass index (BMI), researchers calculated the risk of POAG for each of the dietary patterns.  

What they found

• The participants with the best results were those substituting plant-based fats and proteins for carbohydrates. 
  • Those participants had a 20% lower risk of developing POAG in comparison to those on a high-carbohydrate diet. 
• Researchers did not find any benefit of a low-carbohydrate diet that did not account for the source of protein or fat.
• They also didn’t find an animal-based low-carbohydrate diet to be beneficial to prevent the development of POAG.

What it means

The findings suggest a plant-based low-carbohydrate diet may be the most beneficial for those at risk for POAG. As this is the first study to look at dietary patterns and POAG, Dr. Louis Pasquale, Deputy Chair for Ophthalmology Research for the Mount Sinai Health System, believes more work is needed. 

“It’s important to identify patients who have a genetic make-up of POAG who may benefit from a low-carbohydrate diet,” stated Pasquale. “This dietary pattern may be protective only in people with a certain genetic make-up.” 

*The Mount Sinai Hospital. (2020, July 23). Low-carbohydrate diet may be associated with lower risk of blinding eye disease. Medical Xpress. https://medicalxpress.com/news/2020-07-low-carbohydrate-diet-eye-disease.html