A study of nearly 119,000 adults followed for more than 13 years found coffee and tea consumption was associated with lower dementia risk, while higher intake of sugar-sweetened beverages and, in some groups, artificially sweetened drinks was associated with increased risk.
By yourNEWS Media Newsroom
Daily beverage choices may be associated with meaningful differences in long-term dementia risk, according to a large observational study that followed nearly 119,000 adults for more than 13 years.
The research, published in The Journal of Nutrition, Health and Aging, analyzed data from 118,963 participants in the UK Biobank who were free of dementia at the beginning of the study.
Over an average follow-up period of 13.45 years, researchers documented 992 cases of all-cause dementia.
The findings showed sharply different associations depending on the type of beverage consumed. Coffee and tea were associated with lower dementia risk, while higher consumption of sugar-sweetened beverages was linked to increased risk.
Artificially sweetened beverages were also associated with higher risk among certain participants, particularly those with dyslipidemia.
Because the study was observational, the findings demonstrate associations rather than proving that any particular beverage directly causes or prevents dementia.
Researchers went beyond examining beverages individually by modeling what might happen statistically when one type of drink was substituted for another. That analysis suggested that replacing sugary or artificially sweetened beverages with coffee or tea was associated with lower dementia risk.
Among participants consuming more than one 8-ounce cup of sugar-sweetened beverages per day, the risk of all-cause dementia was 61% higher compared with lower consumption, according to the study.
The category included beverages such as soda, sweetened fruit drinks, energy drinks and sweetened iced tea.
Sugar-sweetened beverages have long drawn attention because of their relationship with metabolic disease. Previous research has estimated that sugary drinks are associated with approximately 183,000 deaths worldwide annually, including about 133,000 deaths from diabetes.
Artificially sweetened beverages produced a more complicated pattern.
Among participants with dyslipidemia, consuming one artificially sweetened beverage per day was associated with a 50% higher dementia risk. Drinking more than one per day was associated with an 80% increase.
Researchers cautioned, however, that artificial sweeteners were analyzed together rather than individually.
The study acknowledged that grouping the sweeteners into a single category “may have obscured potential differences in health effects.”
That limitation is significant because artificially sweetened drinks can contain different compounds with different biological properties.
Previous observational research has also found associations between diet soda consumption and increased risks of dementia and stroke. Other research has examined potential health effects associated with specific artificial sweeteners, including aspartame, which is used in thousands of food and beverage products.
The strongest favorable associations in the new study involved caffeinated coffee and tea.
Participants consuming up to one cup of coffee per day had a 37% lower risk of dementia compared with the reference group, according to the researchers.
Those drinking more than one cup per day had a 24% lower risk.
Tea consumption showed a similar pattern.
Moderate tea intake was associated with a 34% reduction in dementia risk, while consumption of more than one cup per day was associated with a 26% lower risk.
The reported associations were observed specifically with caffeinated coffee and tea. Decaffeinated versions did not demonstrate the same relationship.
The study did not provide detailed information about whether participants drank their coffee or tea plain, with milk or with added sweeteners.
The report noted that heavily sweetened coffee or tea may have been classified separately under sugar-sweetened or artificially sweetened beverage categories, meaning the lower-risk associations could more closely reflect unsweetened varieties.
Coffee and tea also differ substantially from water because they contain numerous naturally occurring compounds in addition to providing hydration.
Both beverages contain caffeine as well as plant-derived compounds that have been investigated for possible effects on inflammation, oxidative stress, metabolism and neurological health.
The researchers also examined whether replacing one beverage with another changed the statistical relationship with dementia.
Replacing sugar-sweetened beverages with coffee was associated with a 23% lower dementia risk.
Replacing them with tea was associated with a 19% lower risk.
The estimated benefit was smaller, but still present, when artificially sweetened beverages were replaced.
Substituting coffee for artificially sweetened drinks was associated with a 15% lower risk, while substituting tea was linked to an 11% reduction.
Those substitution analyses do not demonstrate that changing beverages will necessarily produce the same reduction for an individual person. Instead, they show how dementia risk differed statistically among people whose beverage patterns resembled those substitutions.
The findings were particularly pronounced among participants with certain existing health risks.
Among people with obesity, moderate coffee consumption was associated with a 62% lower dementia risk.
Tea consumption of more than one cup per day was associated with a 52% lower risk in that group.
Researchers reported similar favorable patterns among participants with hypertension, depression and dyslipidemia.
Those results raise the possibility that beverage choices may have a stronger association with brain health among people already facing metabolic, cardiovascular or psychological risk factors.
Dementia, however, develops through a complex combination of influences.
Age, genetics, cardiovascular health, physical activity, body weight, sleep, smoking, alcohol use, diet and other lifestyle factors can all contribute to an individual’s overall risk.
Researchers therefore cautioned against interpreting a single beverage choice as a preventive treatment.
The study instead identified beverages as one potentially modifiable component of a broader lifestyle pattern.
That distinction is especially important because people who regularly drink coffee or tea may differ from heavy consumers of sugary beverages in other ways that are difficult to fully account for statistically.
Dietary patterns can influence cardiovascular and metabolic health, both of which are closely connected to cognitive aging.
Researchers studying neurological disease have increasingly focused on how long-term dietary habits may affect inflammation, insulin resistance, blood-vessel health and other processes associated with changes in the aging brain.
The new findings add to that research by suggesting that beverage selection may be another measurable component of those patterns.
For people consuming large quantities of sugar-sweetened drinks, the study found the clearest unfavorable association: more than one serving per day corresponded with a substantially higher rate of dementia during follow-up.
Coffee and tea showed the opposite pattern, particularly at moderate intake levels.
The results do not establish that coffee and tea prevent dementia or that sugary and artificially sweetened beverages directly cause it. They do, however, suggest that everyday beverage choices may be associated with long-term cognitive health and warrant further study through research capable of examining causation more directly.
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