Alzheimer’s: Can drinking coffee reduce risk?

• There is currently no cure for Alzheimer’s disease, although treatment and lifestyle changes can slow its progression.
• A new Australian study suggests that higher coffee intake might be linked to a slower rate of cognitive decline.
• There was also an association between higher coffee intake and slower accumulation of amyloid deposits in the brain.

More than 55 million people worldwide are living with dementia. The most common type of dementia is Alzheimer’s disease (AD), which experts believe accounts for 50–75% of dementia cases. In an aging population, AD cases are expected to increase.

AD is a complicated disease and not a normal part of aging. It causes complex brain changes that can lead to memory loss and cognitive decline.

A new study in Australia has uncovered evidence to suggest that there is a link between the amount of coffee people drink and their rate of cognitive decline. The study recently appeared in the journal Frontiers in Aging Neuroscience.

Previous research has suggested that coffee might reduce the incidence of cognitive disorders. The authors of this new study set out to explore this further.

Dr. Samantha Gardener, the lead author of the paper, says that if additional research confirms this link, “coffee intake could one day be recommended as a lifestyle factor aimed at delaying the onset of [AD].”

She continues: “It’s a simple thing that people can change […]. It could be particularly useful for people who are at risk of cognitive decline but haven’t developed any symptoms.”

Investigating the link

The research team is based at the Edith Cowan University in Perth, Western Australia. The scientists used data from the Australian Imaging, Biomarkers, and Lifestyle (AIBL) longitudinal study and followed the participants for more than a decade.

The study involved 227 adults aged 60 years or over, who did not have cognitive decline at the start of the study. The team used a questionnaire to gather information from the participants about the amount and frequency of coffee they consumed.

They then performed cognitive assessments using a selection of psychological measures at baseline and 18-month intervals. These assessments measured six cognitive areas: episodic recall memory, recognition memory, executive function, language, attention and processing speed, and the AIBL Preclinical Alzheimer Cognitive Composite (PACC).

PACC is a composite score, combining tests for memory, executive function, and cognition. Research has shown that it can reliably measure the first signs of cognitive decline.

A subset of 60 participants underwent PET brain scans to assess the accumulation of beta-amyloid in the brain. A further subset of 51 participants had MRI scans to assess their brain volume atrophy.

Findings

Analysis of the data showed that habitual coffee drinking was positively associated with the cognitive areas of executive function, attention, and the PACC score. Drinking higher amounts of coffee was associated with slower cognitive decline in these areas over the course of the study.

Higher baseline coffee consumption was also linked to a slower accumulation of amyloid protein over the 126 months.

There did not seem to be a link between coffee intake and brain volume atrophy in this study.

The observed results suggest that increasing coffee intake from 1 to 2 cups per day could potentially reduce cognitive decline by up to 8% after 18 months. There could also be up to a 5% decrease in cerebral beta-amyloid accumulation over the same period.

Dr. Gardener told MNT, “[h]igher coffee intake was associated with slower accumulation of the sticky protein called beta-amyloid, which clumps together in the brains of those with Alzheimer’s disease.”

“This was really interesting to us to establish a potential mechanism, especially as the recently approved medication designed to treat Alzheimer’s disease in the United States, Aduhelm [aducanumab], also works by targeting this protein to reduce its buildup but has been quite controversial and hasn’t shown effects on reducing cognitive decline, which coffee intake has.”

Limitations

It is important to consider the limitations of the study. These include the fact that self-reported dietary data could be subject to recall bias. However, the authors do note that coffee intake is less prone to reporting errors because of its long-term habitual nature.

Secondly, this is quite a small sample size of just 227 people. With a small number of participants, it is harder to draw conclusions about the general population.

Also, the data were not able to show a difference between drinking caffeinated or decaffeinated coffee or to confirm whether the preparation method had any effect.

Dr. Sara Imarisio, head of research at Alzheimer’s Research UK, told MNT, “Studies like this one can provide useful clues about the effects of diet on our brain health, but we must be careful when interpreting the results, as we know many other factors are at play when it comes to dementia risk.”

“This study is not able to pinpoint cause and effect, and no firm conclusions can be drawn about whether coffee has any impact on dementia risk. Participants only reported coffee consumption at the start of the study, so it’s not clear how relevant the findings are to long-term brain health.”

– Dr. Imarisio

MNT asked Dr. Gardener about the generalizability of the results. She said: “The vast majority of our study cohort are [white], and, therefore, generalizability regarding similar effects in other populations may be limited. Additional studies in more varied groups will be required to confirm results are transferable.”

“Our study did not have data on midlife coffee consumption — consequently, potential positive or negative effects of coffee intake at midlife cannot be assessed in the current study.”

Future research 

The authors say that more long-term observational and intervention studies are necessary to confirm these findings.

Dr. Gardener told MNT, “Additional studies with participants followed for [more than] 10 years in a range of different groups of participants, and intervention studies where participants are assigned a specific amount and type of coffee to drink are required to confirm our preliminary findings.”

Dr. Imarisio added:

“Future research into long-term outcomes is needed to further understand the benefits of regular coffee consumption. In the meantime, the best way to keep your brain healthy as you age is to stay physically and mentally active, eat a healthy balanced diet, not smoke, drink only within the recommended limits, and keep weight, cholesterol, and blood pressure in check.”

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