Drinking coffee or tea can have a better impact on health than expected. According to a study carried out recently with data from more than 360 thousand English people, the daily consumption of the two drinks may be associated with a decrease in cases of stroke (cerebrovascular accident) and dementia in people over 50 years of age.
Published in the academic journal PLOS Medicine, the research was done by scientists at Tianjin Medical University in China and Yale University in the United States.
“It is an important issue because we have few options for measures that can prevent or reduce the chance of having, mainly, dementia. So, it is necessary to carry out research of this type to fight a disease that is so prevalent”, comments Polyana Piza, neurologist at the Albert Einstein Hospital (who was not part of the study).
According to the neurologist, approximately 1 million people live with different types of dementia in Brazil. In addition, none of the current treatment options can cure the patient, but only reduce the progression of the disease.
In the case of stroke, in Brazil alone, an average of 400,000 new cases are reported per year. Mortality is also high. Piza cites data from Arpen (Association of Registrars of Natural Persons), which show that in 2020 Brazil registered stroke as the fourth leading cause of death from disease.
For the study, records from 2006 to 2010 from the UK Biobank were used, a database that gathers biomedical information from approximately half a million people living in the UK. As stroke and dementia are more common in the elderly, there was a cut-off for people aged between 50 and 74 years — totaling a sample base of approximately 365,000 people.
The researchers analyzed responses to a questionnaire about coffee or tea consumption—in the case of the latter, the type was not specified, but included black and green tea, both with caffeine in their composition.
Each participant could indicate that they drank less than one glass a day, did not know how to respond, preferred not to pass on this information or indicated the exact amount of glasses ingested daily — and could answer, for example, zero, if they did not take any of the drinks recurrently.
Participants were followed through 2020 to see which ones had developed some type of dementia, suffered a stroke, or were still healthy.
Crossing these data with routine beverage consumption, the researchers found that those who consumed between two and three cups of coffee and two to three cups of tea every day had 32% less risk of having an ischemic stroke and 23% less risk of having an ischemic stroke. having dementia, with the exception of Alzheimer’s — a very common type of the disease, which did not have a reduction in the analysis carried out during the study.
The consumption of drinks without being combined also reduced the chances of having the illnesses. Those who drank just two to three cups of coffee a day had an average 12% decrease in stroke risk, while those who drank the same amount of tea had a 16% contraction of having a stroke.
Another part of the research turned to understanding the development of dementia after suffering a stroke. In this case, more than 13 thousand responses were observed.
According to the researchers, the consumption of three to six cups of coffee and tea every day represented a decrease in the development of some types of dementia. Isolated tea, on the other hand, had no appreciable impact against dementia in stroke patients.
There are some explanations for why tea and coffee prevent stroke or dementia, but the authors themselves claim that animal tests are needed to draw conclusions with greater accuracy.
The article mentions, for example, the fact that beverages are composed of substances, mainly caffeine, which would have an antioxidant and neuroprotective effect, resulting in a reduction in the occurrence of diseases.
Although Piza claims that “the study is well done and has a reliable database” with a large sample of participants, she points out that being observational is a limiting aspect.
Unlike a clinical study, in which there are controlled groups to analyze the effects of a substance, the observational study consists of analyzing data from a population without interference from researchers.
Thus, the doctor says that the research works more as a guide for further investigations that can bring a greater degree of certainty about the impact of beverages on preventing dementia and stroke.
“It is important to validate it with other surveys that also have a large sample, but which are controllable, [contem com] a group that uses coffee or tea compared to a placebo group,” he says.
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