A new study has found that the risk of glaucoma, a fairly common eye condition in the older population that can lead to vision loss , was lower in people who drank hot tea every day.
Glaucoma is an ocular condition characterized by damage to the optic nerve, which may result in partial or total loss of vision. Risk factors for developing glaucoma include age, a medical history of diabetes, obesity, and hypertension.
Coffee consumption has previously been associated with an increased risk of developing glaucoma, due to increased intraocular blood pressure. However, later results have had mixed conclusions.
Most of the research addressing the link between these beverages and the risk of increased intraocular pressure concerns small population samples, and is therefore inconclusive.
Now, a team of scientists from Brown University in Providence, Rhode Island and the University of California in Los Angeles (USA) have decided to compare how consuming various beverages, including hot tea, decaffeinated tea, tea Ice cream, coffee, and soft drinks all influence glaucoma risk.
“The aim of this study is to examine the association between the consumption of various caffeinated and decaffeinated beverages and glaucoma,” the authors clarify.
Lower risk for tea drinkers
The researchers analyzed data obtained from the 2005-2006 National Health and Nutrition Survey, which collected medical data from around 10,000 people. The survey used a wide variety of tools, including interviews, physical examinations, blood samples, as well as an eye test in which 84 participants stood out for some form of glaucoma, with the aim of providing a detailed picture of health in the population from the United States.
As part of their assessment, the participants were asked about their drinking habits, including how much coffee, hot tea, decaffeinated tea, soda, and iced tea they had drunk in the previous year, and how often. They found that participants who drank hot tea every day had a 74% lower risk of developing glaucoma than those who did not.
To ensure consistency of these results, the team also checked for potential confounders, such as a history of diabetes and smoking habits.
No links were found between glaucoma risk and any other type of beverage considered in the study, including coffee, both caffeinated and non-caffeinated, as well as decaffeinated tea, iced tea, and soft drinks.
Is it a causal relationship?
This is only an observational study, so the results must be viewed with caution.
The study also had other limitations, such as the small number of participants with glaucoma and the lack of detailed information on the timing of the diagnosis.
Still, the study authors note in their article that “tea contains phytochemicals and flavonoids [types of active chemical compounds found in plants], which have been shown to have anti-inflammatory, anti-cancer, antioxidant, and neuroprotective properties associated with prevention of cardiovascular diseases, cancer and diabetes “.
Therefore, they suggest, it would not be so exaggerated to consider that the consumption of tea could have a protective metabolic effect.
“More research is needed to establish the importance of these findings and whether the consumption of hot tea can play a role in preventing glaucoma, ” concludes Connie Wu, leader of the work.
Referencia: Frequency of a diagnosis of glaucoma in individuals who consume coffee, tea and/or soft drinks. British Journal of Ophthalmology. 2018 DOI: http://dx.doi.org/10.1136/bjophthalmol-2017-310924
