A 2016 survey conducted by the National Coffee Association revealed that an average of about 56 percent of all Americans 18 years and older drink coffee daily.1 Likewise, on any given day, more than 50 percent of the American population drinks tea.2 Unquestionably, that represents a lot of caffeine being consumed—but is that a good thing or a bad thing? The answer is that it could be either, depending upon the individual. This article will examine the pros and cons of caffeine, but first let's take a look at the common sources of caffeine, and how much of caffeine is provided in each.

Caffeine sources
Coffee and tea are the most prevalent sources of caffeine. An 8 oz. cup of brewed coffee can contain 95–200 mg of caffeine—depending upon who is brewing it. An 8 oz. cup of brewed black tea provides 14–70 mg, and green tea provides 24–45 mg. Cola drinks (regular or diet), provide 23–39 mg per 12 oz. can, and MTN DEW® provides 42–55 mg of caffeine. Energy drinks provide varying amounts of caffeine: 200–207 mg in a 2 oz. 5-Hour Energy shot, and 70–80 mg in a 8.4 oz. can of Red Bull®. Over-the-counter medications can also contribute to total caffeine intake: 65 mg/tablet of Excedrin® Extra Strength, and 200 mg/tablet NoDoz® Max Strength. Even chocolate provides caffeine—104 mg in one cup of semisweet chocolate chips.3 Of course some dietary supplements also contain caffeine. The caffeine may be added as concentrated caffeine anhydrous, or as part of herbal botanical extracts. Guarana, Maté (yerba maté) and cola nut (bissy nut) are examples. The amounts of caffeine provided in the herbs can vary greatly depending on how the herb is processed and concentrated.

Now let's take a look at caffeine's benefits.

The benefits of coffee and caffeine

Despite years of negative press about caffeine, there are, in fact, quite a few significant benefits associated with caffeine intake—and those benefits go beyond energy and weight loss. Following is a brief overview.

Asthma: The use of caffeine in people with asthma has been shown to modestly improve airway function for up to 4-hours in people.4

Diabetes: Consumption of caffeine from beverages such as coffee or tea is associated with a lower risk of developing type 2 diabetes. What's more, this effect appears to be dose-dependent: 200 mg/day caffeine is associated with a 14 percent decrease in the incidence of type 2 diabetes,5 while 417 mg/day caffeine is associated with 20 percent lower risk of developing type 2 diabetes.6

Energy: Caffeine has been shown to reduce fatigue, reduce sleepiness and provide general energizing effects.7,8,9,10,11

Exercise: Research has demonstrated that caffeine increases muscle strength by seven percent and physical endurance by 14 percent,12 and can even decrease subjective feelings of exertion and fatigue during such exercise as fencing and cycling.13

Gallbladder Disease: Also dose-dependent, consumption of caffeine beverages providing 400 mg/day or more caffeine is significantly reduces risk of developing gallstone disease, while 800 mg/day caffeine has the greatest reduction in risk.14 Hypotension: Consuming caffeine beverages has been shown to increase blood pressure in elderly people with low blood pressure following a meal.15

Memory: Memory function was improved in individuals taking 65–200 mg/day caffeine. In research, this included those with extraverted personalities, and college students.16,17,18 Mental Alertness: Caffeine is FDA-approved to help "restore mental alertness or wakefulness during fatigue or drowsiness."19 Other studies have similarly shown that caffeine is beneficial for promoting long-term memory, and improving mental alertness.20,21,22

Migraine Headache: The use of caffeine orally in combination with acetaminophen, aspirin23, and/or sumatriptan24 (a medication used for the treatment of migraine and cluster headaches) is effective for treating migraine headache. In fact, caffeine is FDA-approved for use with analgesics for the treatment of migraine.

Pain: The use of caffeine in combination with pain-relieving agents such as acetaminophen and ibuprofen can reduce acute pain better than pain-relieving agents alone.25

Parkinson's Disease: Large epidemiological studies indicate that people who consume caffeine-containing beverages, such as coffee, tea, and cola, have a decreased risk of Parkinson's disease.26,27

Tension Headache: The use of caffeine in combination with analgesics is effective for treating simple tension headaches.28 As with migraine headaches, caffeine is also FDA-approved for use with analgesics for improving pain relief associated with tension headaches.

Weight Loss: Research has shown that consumption of 100–400 mg/day caffeine increased energy expenditure (calories burned), and thermogenesis (fat burning) and metabolic rate.29,30,31 Caffeine was even found to help reduce waist circumference and body weight.32

Contraindications for caffeine intake
In general, some people are sensitive to caffeine and get the "caffeine jitters" even with relatively small amounts of caffeine, while other people seem to have no negative effects associated with caffeine intake. Clearly, those who are sensitive to caffeine should avoid it since it may cause them to experience insomnia, nervousness, restlessness, gastric irritation, nausea, quickened respiration, tremors, premature heartbeat, arrhythmia and excessive urination (although this latter symptom may occur in anyone who consumes caffeine).33,34,35

It should also be noted that, although acute administration of caffeine can cause increased blood pressure, regular consumption does not seem to increase either blood pressure or pulse, even in mildly hypertensive patients.36,37,38 Also, evidence regarding the relationship between caffeine use and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium. However, moderate caffeine intake, less than 300 mg per day, does not seem to significantly increase osteoporosis risk in most postmenopausal women with normal calcium intake.39,40,41

In any case, individuals with the following medical conditions may need to avoid caffeine or limit its intake. Anxiety Disorders: In some research, caffeine has been shown to aggravate anxiety disorders.42

Bipolar Disorder: In a case study, a 36-year-old man with bipolar disorder was hospitalized with symptoms of mania after consuming several cans of an energy drink (containing caffeine) over a period of four days43.

Cardiac Conditions: Caffeine, taken in high doses (e.g. 750 mg for a 165 lb person), can induce cardiac arrhythmias in sensitive individuals.44

Glaucoma: People with glaucoma should be aware that caffeine increases intraocular pressure. The increase occurs within 30 minutes of ingesting the caffeine, and lasts for at least 90 minutes.45

Conclusion
Caffeine is neither good for everyone, nor bad for everyone. It has many benefits to offer for many people, but care must be taken if you're one of those individuals who are sensitive to caffeine, or who have one of the medical conditions listed under the "Contraindications" section above.

References:

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Gene Bruno, MS, MHS

Gene Bruno is the Dean of Academics and Professor of Dietary Supplement Science for Huntington College of Health Sciences (a nationally accredited distance learning college offering diplomas and degrees in nutrition and other health science related subjects. Gene has two undergraduate Diplomas in Nutrition, a Bachelor’s in Nutrition, a Master’s in Nutrition, a Graduate Diploma in Herbal Medicine, and a Master’s in Herbal Medicine. As a 32 year veteran of the Dietary Supplement industry, Gene has educated and trained natural product retailers and health care professionals, has researched and formulated natural products for dozens of dietary supplement companies, and has written articles on nutrition, herbal medicine, nutraceuticals and integrative health issues for trade, consumer magazines, and peer-reviewed publications. Gene's latest book, A Guide to Complimentary Treatments for Diabetes, is available on Amazon.com, and other fine retailers.