The consumption of coffee and tea is very high throughout the world, so knowing its advantages or disadvantages for health is always interesting and a new investigation is committed to its benefits, in this case for the brain, since it has found a relationship positive relationship between drinking coffee and tea and the thickness of our macular retinal nerve fiber layer, which is an indicator of brain health.
The macula is the central part of the retina at the back of the eye that allows us to enjoy sharp central vision. The retinal nerve fiber layer is a thin layer of nerve cells that transmit visual information from the eye to the brain. “Our findings indicate that if we consume two to three cups of coffee or more than four cups of tea per day, macular thickness will increase,” said Lisa Zhuoting Zhu, MD, principal investigator of the Center for Ophthalmic Epidemiology team. Eye Research Australia (CERA), which has led the new study, which has been published in Nutrients.
As the researcher has explained, the study was inspired by existing evidence that tea or coffee may have protective effects on the brain. “Many cultures drink coffee and tea almost every day, from one to more than five cups, so it is important to be aware of the potential benefits or risks to our health.” And she adds that during the study the thickness of the macular retinal nerve fiber layer was used as a measure of brain health: “The thinner the layer, the greater the risk of neurodegeneration.”
Drink coffee yes, but not too much
The study involved more than 35,000 people who completed a touchscreen questionnaire reporting the number of cups of coffee and tea they drank on average daily over the past year. They divided the participants into four categories: from zero cups to more than four cups per day.
“If we consume two to three cups of coffee or more than four cups of tea a day, macular thickness will increase,” which benefits the brain
The thickness of the macular retinal nerve fiber layer was measured by optical coherence tomography (OCT), a non-invasive imaging technique that uses reflected light to create images of the back of the eye, which was automatically analyzed by a embedded software.
The results showed that coffee drinkers had a significant increase in the thickness of the macular retinal nerve fiber layer, especially those who drank two to three cups of coffee per day. In the case of tea drinkers, a significant increase in macular thickness was also found in those who drank more than four cups a day.
Dr. Zhu noted that they found a “sweet spot” for coffee consumption and having a healthy thickness of the macular retinal nerve fiber layer. “That means not too much, not too little; a medium amount of coffee is best,” she says. And she also cautions that not all coffees are created equal: “Many studies have indicated that instant coffee could be a risk factor for many health problems, including neurodegenerative diseases, which we also found in our study. “That suggests that it is better to have good quality coffee.”
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