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By: George Citroner
A recent study has shown that the amount of coffee consumed may impact its health benefits, adding to existing evidence that drinking coffee can have a broad range of positive eye-health benefits.
Research from the Center for Eye Research Australia has potentially found a link between coffee and tea consumption and the thickness of the macular retinal nerve fiber layer. This layer comprises nerve cells that carry visual information. Its thickness is an important indicator of the macula’s health. The macula is a small area in the retina’s center responsible for clear vision, color perception, and the ability to see fine detail.
The study involved over 35,000 participants from the UK Biobank. This biomedical database keeps in-depth genetic and health information of about 500,000 UK participants, who were asked about their daily coffee and tea consumption over the previous year via a touchscreen questionnaire. Participants were grouped based on their consumption, ranging from nondrinkers to those consuming over four cups daily.
The participants’ macular retinal nerve fiber layer thickness was measured noninvasively using optical coherence tomography. This diagnostic imaging test uses reflected light to produce detailed images and is commonly employed in detecting retinopathy and glaucoma.
The results showed that coffee drinkers had significantly increased macular retinal nerve fiber layer thickness, particularly those drinking two to three cups of coffee daily. But it wasn’t only coffee that provided this benefit.
Tea consumption also increased macular thickness significantly, but only among participants who consumed more than four cups per day.
“Our findings indicate if we consume two to three cups of coffee or more than four cups of tea per day, the macular thickness will increase,” Dr. Lisa Zhuoting Zhu, principal investigator of CERA’s Ophthalmic Epidemiology team, said in a statement.
Fresh Coffee May Be Better Than Instant Coffee
Zhu emphasized that the study found a “sweet spot” for coffee consumption and a healthy macular retinal nerve fiber layer thickness. “That means not too much and not too little—a medium amount of coffee is best,” she said. She also pointed out that coffee quality may be an important factor.
Many people drink instant coffee because it’s readily available. However, “Many studies have indicated that instant coffee could be a risk factor for many health outcomes, including neurodegenerative diseases, which we also found in our study,” she said. “That suggests it’s better to have good quality coffee.”
While the study’s findings are intriguing, Zhu says further studies are needed to validate the results.
Moderation and consulting a health care professional before making significant changes to one’s coffee or tea consumption habits are essential, Dr. Rohan Arora, a neurologist and director of the stroke program at Northwell Long Island Jewish Forest Hills in New York, told The Epoch Times. “More studies are needed to confirm that high intake of coffee and tea can have significant impact in preventing diseases such as Alzheimer’s or Parkinson’s,” he added.
How a Thicker Macular Nerve Enhances Vision
Increased thickness in the macular retinal nerve fiber layer is associated with specific benefits for vision:
Improved visual acuity: A thicker macular nerve layer can help to improve visual acuity, which is the sharpness of vision or clarity.
Enhanced contrast sensitivity: A thicker macular nerve layer may improve contrast sensitivity, which is the ability to distinguish between shades of colors and brightness levels, among older adults.
Reduced risk of macular degeneration: Macular degeneration is a common eye disease that can lead to vision loss. A thicker macular nerve layer may reduce our risk of macular degeneration.
