Spilling the Beans on Coffee and Brain Health

• Caffeine may help protect your brain from memory decline.
• Drinking too much coffee can impact bone density in women.

If you don’t feel like a fully functioning human until you’ve inhaled a steaming mug of coffee in the morning, you’re not alone. Sixty-four percent of Americans report drinking at least one cup on average a day, according to a Gallup poll, and the appeal actually increases with age.

While 50 percent of 18- to 34-year olds consume coffee daily, 74 percent of adults 55 and older say they do the same, the poll reports. 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, as well as a few potential drawbacks. 

Best part of waking up

First, a quick lesson in why you experience that brain boost about 30 minutes after finishing your first cup: That feeling of being awake and alert results from several chemical interactions in the body. Caffeine, a stimulant, blocks receptors for the chemical adenosine, which normally prevents the release of brain-sparking chemicals. “By blocking adenosine receptors, caffeine temporarily prevents this signal from making you feel sleepy,” despite the continued accumulation of adenosine in the brain throughout the day, says Michael Grider, director of the neuroscience program at High Point University in North Carolina.

Caffeine also affects two key hormones: cortisol and adrenaline. Grinder 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.”

In addition, caffeine increases the activity of a group of neurons known as cholinergic neurons, which are involved in attention and arousal, Grider adds. This is another reason for the short-term increase in focus on a test or work project, for example, that is associated with caffeine intake.

Morning jolt

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, a professor in the neurology and biochemistry departments at Georgetown University Medical Center in Washington, D.C. A study published in the Journal of Nutrition found that on tests of mental function, subjects who consumed caffeine had better scores, particularly among older adults. “Indirectly, caffeine is a tool to improve certain types of learning,” Giordano says.

How long does the increased attentiveness last? Research published in Nature Neuroscience shows that caffeine enhances certain memories for up to 24 hours after consumption. “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. (An important footnote is that, in scientific jargon, “short-term memory” is between seven and 15 seconds, whereas “long-term memory” is measured in minutes and hours, not in years, as you might imagine.)

Long-term protection

Additional research suggests that drinking coffee may also help fend off mild cognitive impairment (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. A study from the Journal of Alzheimer’s Disease determined that older individuals who drink one to two cups per day have lower levels of mild cognitive impairment compared with those who don’t drink coffee. (It’s important to note that the same study found that people who hadn’t been regular coffee drinkers beforehand were actually at higher risk for MCI.)

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.”

So what’s the sweet spot to reap the potential brain benefits? The Mayo Clinic recommends up to 400 milligrams 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 brain-boosting perks, researchers have also identified some potential drawbacks that might make you think twice before ordering that latte. In one study published in the American Journal of Epidemiology that involved more than 60,000 women, a high coffee intake was associated with minor decreases in bone mineral density. But Grider, for one, is not overly concerned. “Based on the most recent data available, it appears that decreased bone density does not relate to an increase in bone fractures. Therefore, I would say that coffee is fine unless a person already has advanced osteoporosis.”

Coffee’s impact on sleep is a much greater concern. “As we age, our biorhythm shifts earlier and earlier,” says Jeffrey Ellenbogen, a sleep specialist at the Johns Hopkins University School of Medicine 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.”

In some instances, you may want to rethink your overall coffee habit, at least temporarily. This includes when you’re taking 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, cardiac conditions (such as unstable heart rhythms) and disorders of the parasympathetic and sympathetic nervous systems should check with their doctors before consuming, Giordano advises. 

One last coffee caveat: Adding lots of sugar and cream to your cuppa joe may counter the brain-boosting benefits while also wreaking havoc with your waistline. 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.