Nutrition Articles

The Buzz on Caffeine

Health Benefits and Risks of Caffeine Consumption

Caffeine: Most of us can't get through the day without it. Whether brewing a fresh pot of coffee in the morning, enjoying lunch with a refreshing can of cola, or recharging in the afternoon with an energy drink, we have many routines and food rituals revolving around this energizing substance. Found naturally in the leaves, seeds and fruits of more than 60 plants (including cocoa beans, kola nuts, guarana, yerba mate, green tea extract and tea leaves) and added to many other foods and beverages, caffeine is the world's most popular stimulant. In the US alone, more than 80% of adults consume it. 
Like many commonly enjoyed foods and ingredients, we get mixed information about caffeine. Sometimes we hear it does a body good. Other times, we hear it's bad for us. Keep reading to uncover the truth about caffeine: how it works—and how it affects your health.
Why Caffeine Keeps You Charged
The brain produces a natural sedative called adenosine, which binds to the appropriate receptor sites in the brain, resulting in a drowsy feeling. Adenosine levels rise during daytime/waking hours, encouraging sleep in the evening. While sleeping, adenosine levels drop, so you awaken refreshed and raring to go.  
Caffeine is similar in structure to adenosine. It temporarily binds to adenosine receptor sites in the brain.  This prevents adenosine from attaching itself to the sites and thus, wards off fatigue. If you regularly consume caffeine, you might also discover that you build up a tolerance because the brain makes more receptor sites as a result. Therefore, you need more caffeine to attach to these new sites and get the same results.

While caffeine is one of the most studied ingredients in food supply, there is still great confusion regarding its effects on health. For years caffeine has been included on the U.S. Food and Drug Administration's list of substances that are "generally recognized as safe" (GRAS) list. Extensive research has been conducted on numerous health aspects of caffeine consumption. Here is a synopsis of the findings regarding caffeine and health.
5 Health Benefits of Caffeine
  • Dementia Risk: While it is too soon to tell about caffeine's role in the prevention of dementia in humans, there are some preliminary animal studies showing that it might help to protect against dementia. 
  • Headache Treatment: The blood vessels in the brain dilate (enlarge) during a headache. Caffeine constricts the blood vessels, which lessens the pain. It is also a mild pain reliever. This is why caffeine is found in headache medications like Excedrin Migraine (130 mg per 2 tablets), Midol Complete (120 mg per 2 tablets) and Anacin (64 mg per 2 tablets).
  • Mental Stimulation and Problem Solving: Caffeine has been shown to speed up reaction time and improve processing skills, such as paying attention, solving arithmetic problems, typing and proofreading.
  • Parkinson's Disease: Several preliminary studies have shown that higher caffeine intake can reduce one's risk for developing Parkinson's Disease. In fact, caffeine might help improve tremors and motor skills in people who already have the disease. However, the benefits could lessen as a person develops a tolerance to caffeine. 
  • Physical Performance: Low to moderate doses of caffeine (200-300 mg) have been shown to improve athletic performance in well-trained athletes, especially in endurance events like running. However, in sports that require short bursts of movement like weight lifting or sprints, caffeine is less effective. Caffeine might help with the burning of fat for energy after exhausting the carbohydrates stored in the muscles. Caffeine also helps reduce the feeling of muscle pain and tiredness, so one feels better while exercising.
4 Health Risks of Caffeine Consumption
  • Complex Tasks: Caffeine can worsen performance on complicated tasks, and with caffeine usage over time, the mental boost one gains from caffeine is reduced.
  • Fertility and Pregnancy: The March of Dimes recommends that women who are pregnant or trying to get pregnant consume no more than 200 milligrams of caffeine per day due to possible adverse effects on fertility, miscarriage and fetal growth.
  • Fibrocystic Breast Disease: While it does not cause this condition, caffeine can aggravate the symptoms in some women who already have the disease. 
  • Sleep: Consumed later in the day, caffeine can interfere with the onset of sleep and especially rapid eye movement (REM) sleep. Most people report difficulty falling asleep when consuming caffeine within six hours before going to bed. Your sensitivity will vary based on how quickly your body metabolizes caffeine, the amount you ingest and your regular consumption amount.  
6 Things Caffeine Has NO Affect On
  • Cancer: Current research does not show a link between caffeine intake and cancer in humans. 
  • Dehydration: Caffeine is a mild diuretic that can increase the frequency of urination. However, the fluid you consume in the caffeinated beverage tends to offset the fluid loss when you urinate. Studies have shown that caffeinated beverages do not cause dehydration. 
  • Heart Disease or High Blood Pressure: Caffeine has not been shown to increase the risk for cardiac arrhythmias, coronary heart disease, stroke or the development of chronic hypertension. It has not been shown to increase cholesterol levels or alter lipid profile.
  • Osteoporosis: Caffeine has not been shown to be a risk factor in the development of osteoporosis, especially in adults with adequate daily calcium intake. It does not alter calcium absorption or excretion significantly.
  • Reduced Intoxication: When intoxicated from too much alcohol intake, caffeine does not "sober you up" faster.
  • Weight Loss: Because caffeine is a stimulant, it does speed up metabolism, but the effect is only minimal and very short term. Clinical research does not show a significant weight loss with the use of caffeine-containing supplements. Therefore, save your money and leave those supplements (which can contain up to 300 mg of caffeine per dose) on the store shelf.  
How Much Caffeine Are You Consuming?
While a moderate caffeine intake up to 400 milligrams a day is considered safe for a healthy adult, it is not mandatory for the amount of caffeine to be listed on the label of foods, beverages or supplements.  Therefore, determining your daily intake can be difficult. The chart below shows estimated caffeine contents in commonly used foods, beverages and pills. The amount will vary based on ingredients used, brewing method, brewing time and a company's formula.

Other nutritional supplements, such as weight-loss supplements, vitamin-mineral supplements, and sport-enhancing supplements might also contain caffeine in varying amounts. To determine if a supplement contains caffeine, look for plant names that contain caffeine on the ingredient list such as guarana, yerba mate, kola nut and green tea extract. Since products and formulas change, contact the company to see if the exact caffeine amount is available.  

Product Caffeine (mg) 
Brewed coffee, 8 oz 80-160
Instant coffee, 8 oz 50-90
Decaf coffee, 8 oz 3-8
Alertness medication, pill 100-200
Appetite suppressants, pill 100-200
Headache medication, pill 65
Brewed black tea, 8 oz 30-90
Yerba mate, 8 oz 85
Instant tea, 8 oz 25-50
Iced tea, 8 oz 10-50
Green tea, 8 oz 25
Herbal tea, 8 oz 0
Flavored Milks:  
Chocolate milk, 8 oz 2-7
Chocolate soy milk, 8 oz 4-5
Soft Drinks:  
Mountain Dew, 12 oz 54
Cola, 12 oz 35-50
Root beer, 12 oz 0-25
Energy Drinks:  
Energy shots, 1.9 oz 200
Energy drinks, 8 oz 80-100
Energy vitamin water, 20 oz 50
Energy gum, per piece 35-100
Coffee ice cream, 4 oz 20-50
Dark chocolate, 1.5 oz 10-50
Milk chocolate, 1.5 oz 5-20
Hot chocolate, 8 oz 13
Chocolate flavored syrup, 1 oz   4-5
Chocolate ice cream, 4 oz Less than 1

Cutting Back on Caffeine:  If you decide it's time to cut back on your caffeine intake, there are two basic approaches you can try:
  • Go Cold Turkey: Consider all of the typical sources of caffeine that you might consume, then remove some or all of them at once to reach your desired upper limit of caffeine per day. You will probably experience caffeine withdrawal symptoms such as headaches, drowsiness and tiredness. These discomforts usually subside in 4-7 days.
  • Cut Back Slowly: Determine your typical daily caffeine intake and sources of caffeine. Remove about 50 milligrams of caffeine from your diet to start. Stay at this amount for several days to allow your body to adjust. Then cut back another 50 milligrams. Continue with this process until you reach your desired level of caffeine consumption.  
The Final Scoop 
In moderation, caffeine can increase alertness, performance, productivity and may have some health benefits. Too much, however, can ove-stimulate the nervous system and bring about restlessness, irritability, and insomnia. Based on current evidence, the U.S. Beverage Guidance Panel suggests that moderate caffeine intake up to 400 milligrams a day is safe for healthy adults and is not associated with increased risk of heart disease, hypertension, osteoporosis or high cholesterol. Discuss your daily caffeine intake plan with your doctor as it relates to your medical conditions and tolerance. 
Note:  This article was specifically researched and written regarding caffeine intake and the adult population. Refer to the American Academy of Pediatrics for information on caffeine intake for children and adolescents. 
Aedma M, Timpmann S, Ööpik V. "Effect of Caffeine on Upper Body Anaerobic Performance in Wrestlers in Simulated Competition Day Conditions." Int J Sport Nutr Exerc Metab. 2013 May 22.
Center for Science in the Public Interest, "Caffeine Content of Food and Drugs,", accessed on October 21, 2013.
EnergyFiend, "Caffeine Amounts,", accessed on October 21, 2013.
Eskelinen MH, Kivipelto M. "Caffeine as a protective factor in dementia and Alzheimer's disease." J Alzheimers Dis. 2010;20 Suppl 1:S167-74.
Hodgson AB, Randell RK, Jeukendrup AE. "The metabolic and performance effects of caffeine compared to coffee during endurance exercise." PLoS One. 2013;8(4).
Hursel R, Viechtbauer W, Westerterp-Plantenga MS. "The effects of green tea on weight loss and weight maintenance: a meta-analysis." Int J Obes (Lond). 2009 Sep;33(9):956-61.
Lieberman JA, Sylvester L, Paik S. "Excessive sleepiness and self-reported shift work disorder: An internet survey of shift workers." Postgrad Med. 2013 May;125(3):162-71.
March of Dimes, "Caffeine in Pregnancy,", accessed on October 21, 2013.
Nawrot P, Jordan S, Eastwood J, Rotstein J, Hugenholtz A, Feeley M.
"Effects of caffeine on human health." Food Addit Contam. 2003 Jan;20(1):1-30.
Palacios N, Gao X, McCullough ML, Schwarzschild MA, Shah R, Gapstur S, Ascherio A. "Caffeine and risk of Parkinson's disease in a large cohort of men and women." Mov Disord. 2012 Sep 1;27(10):1276-82.
Rosalie Marion Bliss, ARS. "Caffeine-Containing Botanicals in Dietary Supplements," Agricultural Research, April 2009.
Sengpiel V, Elind E, Bacelis J, Nilsson S, Grove J, Myhre R, Haugen M, Meltzer HM, Alexander J, Jacobsson B, Brantsaeter AL. "Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study." BMC Med. 2013 Feb 19;11:42.
Snel J, Lorist MM. "Effects of caffeine on sleep and cognition." Prog Brain Res. 2011;190:105-17.
The Nutrition Transition, "Tea, Coffee, Unsweetened,", accessed on October 21, 2013.

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Member Comments

  • I only drink one or two glasses of Crystal light energy packets per day. I drink water the rest if the day. I'll enjoy a coffee now and again, but it's rare that I do.
  • I disagree with the article~ I think the world is addicted to coffee as evidenced by many comments. Yes, I will take a cup, that is once in a great while ,but I think there are MANY MORE benefits to Herbal tea than coffee. Besides ,really , isn't it about the ADDITIVES everyone puts in coffee~another way to keep the sugar habit going. No, I do not put sugar in my tea. But I have a sugar habit going that I am trying to get rid of~called ~cookies!
  • Love the article but have to say that when I am decaffeinate the world at large is in danger. '-)

  • I enjoyed this and I have to say some of this I did not know about coffee. Thank you.
  • I have gone for years without the caffeine - actually got addicted to it some as a younger adult with headache medicines with it and coffee -- Have very slowly begun to try a little again, but have to be careful to stop by later afternoon if I want to sleep by 10 p.m. Have been more motivated to try it some in order to see how it affects my ADHD adult daughter and that experiment is still in progress.
  • This lovely cup of Dunkin Donuts iced coffee right here, with skim milk and three packs of Equal?
    This is all that's standing between most people and certain annhilation, because my patience is already short and my grip on my temper is tenuous at best.
  • I've been caffeinated and decaffeinated. I prefer to be caffeinated. The good news is that I know when I've had enough--even when I'm tired. I can't drink more than I can handle.
  • I drink 4-5 coffees everyday, and being in Italy, they're quite strong. I have stopped drinking it after 4-5 pm though, cause it worsen my sleep problems. I have a low blood pressure and I suffer from headaches from time to time, so I guess it helps!
  • YELLOWDUCK60 there's a caffeine chart on pg 3 that shows for tea as well as other drinks :)
    Hi lots of talk about coffee - nothing really said about a refreshing cup of weak tea. I drink alot of it - its just about hot water with milk- with a hint of tea. I would be interested to know what that caffeine content of that would be.
    I drink coffee infrequently and find purchased coffees too strong for me.
  • I love and adore coffee-drink it every day. But every once in a while -I quit coffee to give my body/brain a break from it. .And I find It takes about a month for my brain to re-wire to be able to have my own energy again. For that month I notice it is harder to think as quick /move as I do with the caffeine.But I have learned that I have to quit slowly. One time I tried to quit cold. and looking for an exit at the car wash, I accidentally drove my car off a curb that at one time had been a driveway ( it still sort of looked like one). I realized right there and then, with my car stuck on that curb-that withdrawal from coffee -I need to be careful for the first day or two! I would not have made such a judgement error had I had my morning joe.
  • I tried giving up caffeine once. It was the worst dietary change I ever made. I will never do that again, unless some horrible global catastrophy happens, and suddenly humanity runs out of coffee.
  • Nicely balanced article. Thanks.
  • I have Fibrocystic Breast Disease and had to quit caffeine and take Vitamin E as per the doc's request. Big improvement in my health which saved me from surgery.

    The only problem with going caffeine free is when you go out to dinner and ask what they have that is decaffeinated and diet, you will get a plethora of crazy answers from tea to Diet Coke. I started ordering the water with lemon.
  • I so agree... My grandmother is a healthy 92 year old, that for as long as I can remember, has always had a cup of coffee each morning with her prayers.
    Her only pain is arthritis.

About The Author

Becky Hand Becky Hand
Becky is a registered and licensed dietitian with almost 20 years of experience. A certified health coach through the Cooper Institute with a master's degree in health education, she makes nutrition principles practical, easy-to-apply and fun. See all of Becky's articles.

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