Boiled coffee overload: Consuming six or more cups daily linked to higher dementia and Alzheimer's risk

By Bhavana KunkalikarReviewed by Benedette Cuffari, M.Sc.May 30 2023

In a recent study published in the journal Nutrients, researchers examine the potential relationship between tea and coffee consumption during midlife and the risk of developing dementia in later life.

Study: The Association between Coffee and Tea Consumption at Midlife and Risk of Dementia Later in Life: The HUNT Study. Image Credit: ImYanis / Shutterstock.com

The health benefits of caffeine

Tea and coffee are widely consumed beverages globally and are rich in bioactive plant compounds. Regular caffeine consumption has been found to decrease amyloid-β levels and neuroinflammation, as well as improve cognitive function in animal models.

Observational studies investigating the link between tea and coffee consumption and the risk of dementia have produced inconsistent results. Whereas some studies have shown that increased tea and coffee intake, in combination or separately, may be correlated to lower dementia risk, other studies have not reported this association.

About the study

In the present study, researchers investigate the potential correlation between the intake of tea and coffee during midlife and the subsequent long-term risk of developing Alzheimer’s disease (AD), mild cognitive impairment (MCI), and all-cause dementia.

The HUNT Study was conducted in four surveys since 1984. The HUNT4 study included a specific investigation on aging, known as HUNT4 70+.

People aged 70 years or above, whether living in the community or long-term care facilities, were recruited for the study. Participants from HUNT2 were recruited between 1995 and 1997 and later participated in the HUNT4 70+ study between 2017 and 2019.

A self-reported questionnaire was used to evaluate the consumption of tea and coffee during HUNT2. Participants were instructed to record their daily intake of boiled coffee, tea, and different coffee types.

The primary study outcome was cognitive status at HUNT4, which was evaluated 22 years after exposure evaluation. The diagnosis of MCI and dementia was made using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. 

Dementia subtypes are identified according to clinical symptoms and classified into categories such as vascular dementia, AD, Lewy body dementia, mixed dementia, frontotemporal dementia, or other specified or unspecified dementia. Here, the researchers primarily focused on determining the general risk of developing dementia. Secondary outcomes involved the risk of AD and MCI.

Several models were used to analyze the data, the first of which included sex and age, while the second model included additional factors such as marital status, educational attainment, smoking, alcohol consumption, physical activity, and tea/coffee consumption.

The third model further adjusted for body mass index (BMI), history of cardiovascular disease, and diabetes. Finally, in model four, the analyses were adjusted to assess the link between various coffee types and the risk of dementia and account for alternative types of coffee.

Study findings

The HUNT2 and HUNT4 70+ studies involved 8,758 participants, with an average follow-up time of approximately 22 years. A total of 7,381 individuals were available for the main analyses after exclusions.

Daily intake of eight or more cups of coffee was associated with a higher risk of developing dementia compared to those who consumed zero to one cup of coffee daily. However, after accounting for confounding factors, the link between coffee and dementia weakened.

No significant links were discovered between general coffee intake and the risk of dementia. Additionally, there was no relationship between tea intake and dementia risk.

Daily intake of at least six cups of boiled coffee correlated with an increased risk of dementia risk when compared to those who consumed zero to one cup of boiled coffee every day. However, the association between boiled coffee intake and dementia was not present after adjusting for other coffee types.

No associations were observed between other levels of boiled coffee consumption and dementia. Adjustment models two and four revealed that drinking four to five cups of coffee every day, other than the general coffee type, was linked to a lower risk of dementia in comparison to consuming zero to one cup daily.

Daily consumption of four to seven cups of boiled coffee was associated with a higher risk of MCI as compared to those who consumed zero to one cup of boiled coffee. No correlation was observed between the risk of MCI and regular intake of other types of coffee.

Consuming more than six cups of boiled coffee daily was associated with an increased risk of AD, while the consumption of other types of coffee was not associated with AD risk. Furthermore, the risk of MCI or AD was not linked to daily tea consumption.

Consuming six to seven cups of boiled coffee increased the risk of dementia in individuals who do not carry the apolipoprotein E ε4 (ApoE4) gene, compared to those who consume zero to one cup of boiled coffee. However, this correlation was not observed in ApoE4 carriers.

Conclusions

Drinking four to seven cups of boiled coffee every day increased the risk of MCI, whereas consuming six or more cups of boiled coffee each day was associated with a greater risk of AD. No correlation was found between the risk of MCI or AD and the consumption of other types of coffee.

Boiled coffee was associated with increased dementia risk among women and those without the ApoE4 gene, while other types of coffee were linked to lower dementia risk in men. No association was observed between tea consumption and the risk of developing dementia.

Further research is needed to determine the potential correlation between coffee consumption, dementia risk, coffee type, gender, and ApoE4 carrier status.