Where Do You Draw the Line on Caffeine?

Tuesday Jul 14 | BY |
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young addict business man in suit and tie holding cup of take away coffee against crazy maniac face in caffeine addiction isolated on grey background

Some caffeine may be good for you, but how much is too much?

It wasn’t that long ago that the general perception of caffeine was negative. Recent studies, however, have indicated that caffeine can be beneficial to health in some cases—especially when consumed in tea, coffee, dark chocolate and other items that contain healthy antioxidants.

Still, that doesn’t mean we have carte blanche on caffeine, and can consume as much as we want without fear of negative effects. But just how much is too much?

Healthy Effects of Caffeine

Though long considered something that worked against health, caffeine seems to actually has some health benefits, when taken in the right way. We have a lot of studies showing coffee to be good for us, reducing risk of cancer, diabetes, dementia, stroke, and Parkinson’s disease.

Many times, however, it’s unclear whether it’s the caffeine or the antioxidants in the coffee that are creating the benefits. We do have some studies, however, that isolated the effects of caffeine. Here’s a glimpse of the research so far:

  • Improves memory: According to the Johns Hopkins University, caffeine has a positive effect on long-term memory. Whether consumed in coffee, tea, or a can of soda, the stimulant was found to enhance certain memories for up to 24 hours. “We’ve always known that caffeine has cognitive-enhancing effects,” said senior author Michael Yassa, “but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans. We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours.”
  • Protects from breast cancer: Swedish researchers recently reported that caffeine turns off the signal paths to breast cancer cells, slowing proliferation and increasing cell death. Women in the study who drank at least two cups of coffee a day reduced risk of relapse by almost half over those who drank smaller quantities or no quantities at all—and researchers determined it was the caffeine that had the impact on cancer signaling pathways.
  • Improves blood flow: A Japanese study in 2013 found that caffeinated coffee created a 30 percent increase in blood flow through the small vessels in the fingertips, compared with a cup of decaf. The effects lasted for over a 75-minute period. Previous studies have linked coffee consumption with a reduced risk of heart disease—this study suggested that it’s the improvement in blood flow that may have something to do with these positive effects.
  • Reduces depression: A Harvard School of Public Health study of 50,000 women found that caffeine may lower incidence and intensity of depression. Those who drank four cups of caffeinated coffee a day had a 20 percent lower risk of developing clinical depression than those drinking one cup or less per week.
  • Protects against Alzheimer’s: Several studies have indicated that coffee can protect against Alzheimer’s and other forms of dementia. A 2014 study narrowed it down to the caffeine. Researchers found that caffeine had a positive effect on the “tau deposits” in the brain that are characteristic of Alzheimer’s. Regular doses slowed memory decline.

Other studies have indicated that coffee drinkers enjoy heightened mental alertness, improved muscle coordination, and may even enjoy a longer life. In these studies, we can’t be sure if it’s the caffeine or the coffee providing the benefits, or some combination of both.

Either way, recent evidence indicates that in moderate amounts, caffeine can be good for us. But we all know the feeling when we’ve had too much—the shakiness, jitteriness, insomnia, and more.

Possible Adverse Effects of Caffeine

Meanwhile, we have other studies indicating that caffeine can be harmful to our health.

  • Motor learning: A 2008 study compared consuming caffeine with napping and their effects on learning. They found that naps were much more effective in enhancing recall than caffeine, and that caffeine actually impaired motor learning.
  • Anxiety and panic attacks: Several studies have indicated that caffeine, particularly in doses of 400 mg or more, can increase anxiety, and can also exacerbate panic in individuals that suffer from generalized anxiety. Normal consumption of coffee is rarely linked with anxiety.
  • Hallucinations: High daily doses of coffee (about seven cups or 300 mg a day) are more likely to suffer from hallucinations compared to those who drink about three cups a day or less.
  • Dependency: Consistently consuming too much caffeine can lead to dependence, which can create negative withdrawal symptoms including headaches, depression, and fatigue.
Too Much of a Good Thing

Try to find out how much caffeine is too much for good health and you come up with a number of different suggestions. There’s also a wide variance between people—your overall health condition, age, and regular consumption of caffeine can all factor into how much you can tolerate without noticing negative effects.

“Caffeine can also metabolize at different rates among individuals for various reasons,” Steven E. Meredith of the Johns Hopkins University School of Medicine told Medical News Today. “For example, cigarette smokers metabolize coffee twice as fast as non-smokers.”

Caffeine metabolism is slower in pregnant women, individuals with liver disease, and those taking some medications.

As we review all the recommendations and evidence, we can determine general amounts that are safe for most people.

For your reference: a single espresso provides about 80 mg of caffeine, while a regular cup of coffee has about 90 mg. A standard energy drink contains about 80 mg. A standard soda contains 40 mg, and a bar of plain chocolate contains about 25 mg (milk chocolate has only about 10 mg).

  • 500-600 mg: The Mayo Clinic says that this much or more of caffeine can lead to nervousness, restlessness, insomnia, irritability, an upset stomach, rapid heartbeat, and even muscle tremors.
  • 400 mg: The European Food Safety Authority (ESFA) states that up to 400 mg from a range of sources is a safe level for most healthy adults. (This amounts to about 4 cups of coffee a day.)
  • 200 mg: Johns Hopkins Medicine states that 20-200 mg of caffeine a day generally produces positive mood effects, whereas more than that can cause anxiety and nervousness.
  • 500 mg: The U.S. Food and Drug Administration (FDA) reports that 500 or more mg of caffeine a day is considered a high daily dose, and has been linked with negative health consequences.
Bottom Line

How much caffeine is too much for you? Only you can answer that question, but here are some general guidelines:

  • Three-to-four cups a day of regular coffee is considered safe and beneficial for most people.
  • Up to 400 mg of caffeine a day is likely to be safe for most healthy adults.
  • Caffeine is transmitted through the placenta and through breast milk to baby. The FDA recommends pregnant and breastfeeding women stop taking caffeine or cut back to 1 cup per day.
  • If you are anxious or prone to panic, you may want to avoid caffeine altogether.
  • Watch for possible effects of too much: headaches, anxiety, irritability, nervousness, or withdrawal symptoms.
  • Remember to count all sources of caffeine when tallying up your daily consumption—coffee, tea, chocolate, energy drinks, soft drinks, etc.
  • Be particularly careful with energy drinks—the Substance Abuse and Mental Health Services Administration has called them “a continuing public health concern” because of the rise in energy-drink-related emergency-room visits. (They increased from fewer than 2,000 in 2005 to over 20,000 in 2011.)
  • Be wary of caffeine powder—one teaspoon can contain the equivalent of 25 cups of coffee. The FDA issued a warning in 2014 urging people to avoid it.

What is your limit on caffeine consumption? Please share your thoughts with our readers.

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Daniel Borota, et al., “Post-study caffeine administration enhances memory consolidation in humans,” Nature Neuroscience, 2014; 17:201-203, http://www.nature.com/neuro/journal/v17/n2/full/nn.3623.html.

Latarsha Gatlin, “Caffeine has positive effect on memory, Johns Hopkins researchers say,” Johns Hopkins University, January 12, 2014, http://hub.jhu.edu/2014/01/12/caffeine-enhances-memory.

“Healthy caffeine: Study proves coffee can ward off breast cancer,” RT News, April 19, 2015, http://rt.com/news/251041-coffee-cancer-prevention-study/.

Dennis Thompson, “Does Caffeine in Coffee Perk Up Heart Health?” Consumer HealthDay, November 20, 2013, http://consumer.healthday.com/vitamins-and-nutrition-information-27/caffeine-health-news-89/does-caffeine-in-coffee-perk-up-heart-health-682333.html.

Marsha R. Sakamaki, “Is Caffeine a Miracle Drug?” Natural Awakenings, March 2015, http://www.naturalawakeningshawaii.com/Natural-Awakenings-Hawaii/March-2015/Is-Caffeine-A-Miracle-Drug/.

“Scientists discover big clue to how caffeine wards off Alzheimer’s,” MedicalNewsToday, April 8, 2014, http://www.medicalnewstoday.com/articles/275181.php.

Zachary Sniderman, “How Much is Too Much Caffeine?” Greatisti, April 27, 2012, http://greatist.com/health/how-much-too-much-caffeine.

“Five espressos’ worth of caffeine could be damaging to health, warns EU,” The Guardian, May 27, 2015, http://www.theguardian.com/world/2015/may/27/caffeine-intake-five-espressos-damage-health-eu-food-standards.

“Caffeine Dependence,” Johns Hopkins Medicine, http://www.hopkinsmedicine.org/psychiatry/research/BPRU/docs/Caffeine_Dependence_Fact_Sheet.pdf.

Mednick SC, et al., “Comparing the benefits of caffeine, naps, and placebo on verbal, motor, and perceptual memory,” Behav Brain Res., November 3, 2008; 193(1):79-86, http://www.ncbi.nlm.nih.gov/pubmed/18554731.

Leeana Aarthi Bagwath Persad, “Energy Drinks and the Neurophysiological Impact of Caffeine,” Front Neurosci., 2011; 5:116, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3198027/?tool=pubmed.

James Hamblin, “How Much Caffeine Before I End Up in the E.R.?” The Atlantic, January 15, 2013, http://www.theatlantic.com/health/archive/2013/01/how-much-caffeine-before-i-end-up-in-the-er/267129/.

“Caffeine: how does it affect our health?” Medical News Today, June 10, 2015, http://www.medicalnewstoday.com/articles/271707.php.

“FDA Consumer Advice on Powdered Pure Caffeine,” FDA, 2014, http://www.fda.gov/Food/RecallsOutbreaksEmergencies/SafetyAlertsAdvisories/ucm405787.htm.

“Caffeine,” Brown University, http://brown.edu/Student_Services/Health_Services/Health_Education/alcohol,_tobacco,_&_other_drugs/caffeine.php.

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho. www.colleenmstory.com

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