Spilling the Beans on Coffee and Brain Health

Caffeine may help protect long-term memory, but has some downsides

Michele Shapiro

Updated April 15, 2025

A close-up view of four spoons with different coffee beans

Maximilian Stock Ltd/Getty Images

Caffeine may help protect your brain from memory decline.
Drinking too much coffee can cause sleep problems as you age.

You're not alone if you don’t feel like a fully functioning human until you’ve downed a steaming mug of coffee in the morning. Daily coffee consumption is at a 20-year high. And the greatest increase is among consumers 60-plus, according to the National Coffee Association’s 2024 report. Among those older adults, 73 percent reported drinking coffee the day before, compared with 67 percent in 2004. 

While the mental jolt you experience after a java fix is very real, research suggests there may be some additional benefits to your morning or midafternoon cup, plus a few potential drawbacks.

Best part of waking up

First, a quick lesson in why you experience that lift about 30 minutes after finishing your first cup: That feeling of being awake and alert results from several chemical interactions in the body.

Caffeine is a stimulant. It blocks receptors for the sleep-inducing chemical adenosine. “By blocking adenosine receptors, caffeine temporarily prevents [adenosine’s] signal from making you feel sleepy,” despite the continued accumulation of adenosine in the brain throughout the day, says Michael Grider, assistant professor of neuroscience at High Point University in North Carolina. It also boosts levels of two key hormones: cortisol and adrenaline. Grider explains that adrenaline increases alertness, heart rate, blood pressure and body movement. “Cortisol is the body’s main stress hormone, and it increases the body’s stress response,” he says.

Caffeine also increases the activity of a group of nerve cells in the brain known as cholinergic neurons, which are involved in attention and arousal, Grider adds. This is another reason coffee provides a short-term increase in focus on a test or work project, for example.

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Attention helps memory

All three of these chemical reactions in the brain increase attentiveness. “The more attentive we are, the more we tend to remember,” says James Giordano, Pellegrino Center professor of neurology and biochemistry at Georgetown University Medical Center in Washington, D.C.

A 2021 review of caffeine-related studies concluded that caffeine has significant positive effects on both short- and long-term memory in adults. “A moderate dose of caffeine can facilitate the short-term retention of information, which then has a good shot of being encoded into long-term memory,” Giordano says.

Long-term protection

Additional research suggests that drinking coffee may also help fend off mild cognitive impairment, or MCI, the decline in one’s cognitive abilities beyond expected changes related to aging. MCI is often, but not always, a precursor to Alzheimer’s disease.

Researchers from Edith Cowan University in Australia sought to determine whether coffee intake affected the rate of cognitive decline of more than 200 volunteers. Higher coffee intake was associated with slower decline in executive function and attention and a lower likelihood of reaching MCI or Alzheimer’s disease over 10 years. Higher coffee intake seemed to be linked to slowing the accumulation of the amyloid protein in the brain, a key factor in the development of Alzheimer’s disease, as reported in 2021 in Frontiers in Aging Neuroscience.

But when it comes to coffee, more isn’t always better. In fact, high doses can have a negative effect on memory and attentiveness, Giordano says. Plus, “the more coffee you drink, the more used to the caffeinated effect you’ll get, and the more you’ll need,” he cautions.

So, what’s the sweet spot to reap the potential brain benefits? The Mayo Clinic recommends up to 400 milligrams of caffeine daily — about four cups of coffee — for most adults. But how many cups you can safely consume a day depends on several factors, including your size and liver function, says Grider, who adds that genetics and diet can also influence how fast your body breaks down caffeine.

Potential problems

Despite coffee’s potential perks, studies suggest that older adults may be more sensitive to caffeine than younger people. Coffee’s impact on sleep is an overall concern. “As we age, our biorhythm shifts earlier and earlier,” says Jeffrey Ellenbogen, M.D., a sleep specialist and neurologist who is director of The Sound Sleep Project in Baltimore. “We tend to go to bed and wake up earlier. Caffeine lasts in our bodies for about seven hours, so that late-afternoon cup of coffee begins to encroach on bedtime, making it hard to fall asleep.”

Cutting out the late caffeine may even help people already dealing with cognitive decline get some sleep. In one interventional study reported in 2018 in European Geriatric Medicine, 21 nursing home residents with dementia got better sleep after eliminating caffeine intake in the afternoon and evening over a six-week period.

People taking certain supplements or medications may want to rethink their overall coffee habit. This can mainly come into play with over-the-counter (OTC) supplements for weight loss or memory boosting. “Many OTC treatments contain stimulants that, when taken with caffeine, can have negative effects,” Giordano says.

In addition, if you are prone to high blood pressure or taking medications for low blood pressure, caffeine might not be a good idea. Lastly, those with acid reflux, heart conditions (such as unstable heart rhythms) and disorders of the parasympathetic and sympathetic nervous systems should check with their doctors before drinking coffee, Giordano advises.

One final caveat: Adding lots of sugar and cream to your cuppa joe may wreak havoc with your waistline, which is not good for your brain health. So, it pays to be mindful about what you’re putting in your coffee as well as how many cups a day you’re consuming.