Drinking regular tea and coffee may reduce the risk of dementia, a new study has claimed, with researchers able to pinpoint the number of cups each day linked to reduced risk.
Those who drink caffeinated versions of tea and coffee also have better mental skills compared to people who do not, experts found.
Researchers from Harvard University in the US found that higher caffeinated coffee intake was significantly associated with lower dementia risk – those who drank the highest amount of coffee compared to the lowest appeared to have an 18% reduced risk of dementia.
People who drank the most tea appeared to have a 16% reduced risk.
Those who consumed the most tea and coffee also showed a slower rate of cognitive decline compared to those who drank the least.
Drinking decaffeinated coffee was not associated with lower dementia risk or better cognitive performance.
How significant is this new research?
Lead author Yu Zhang from the TH Chan School of Public Health at Harvard University said: “Coffee and tea are widely consumed globally, so even modest associations could have meaningful population-level implications.”
Dr Susan Kohlhaas, executive director of research at Alzheimer’s Research UK, cautioned against reading too much into the study, saying: “This research doesn’t prove that coffee or tea protect the brain.
“This study shows an association, not a cause-and-effect relationship.
“People who drink coffee or tea may also differ in other ways that affect brain health, even after careful adjustment, and the study relied partly on self-reported diagnoses.
“It was also conducted in relatively similar groups of health professionals, which limits how widely the results can be applied.”
What did the study involve?
The researchers examined data on 131,000 health workers, who were tracked for an average of 43 years.
This included 86,000 female NHS nurses and 45 men working as health professionals in the US.
Questionnaires about their diet were completed every two to four years, including questions about caffeinated coffee, decaffeinated coffee and tea consumption.
Cognitive tests were also performed.
During the follow-up period, 11,033 cases of dementia were identified.
Among the NHS nurses, higher caffeinated coffee consumption was also associated with better objective cognitive performance.
Higher intake of tea showed similar associations, researchers found.
Overall, the authors found that the most “pronounced association” was among people who drank a “moderate” amount of tea or coffee, with “no additional advantages” among people who consumed more.
What did experts find to be the right amount?
Researchers estimated that drinking two to three cups of caffeinated coffee each day, or one to two cups of tea per day, was linked with the lowest risk of dementia compared to people who did not drink these drinks.
“Greater consumption of caffeinated coffee and tea was associated with lower risk of dementia and modestly better cognitive function, with the most pronounced association at moderate intake levels,” they wrote in Jama.
Dr Zhang added: “We observed the most favourable associations were at moderate intake levels – the strongest associations were seen at about two to three cups per day of caffeinated coffee and about one to two cups per day of tea.
“We didn’t observe additional benefits at higher intake levels.”
Source: ITV News
--Agencies
