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The Negative Side Effects of Caffeine Explained

Although caffeine can be consumed at a safe level, an excessive amount can lead to unpleasant side effects. Caffeine is a drug, after all. Here are just a few negative effects of overconsumption.

The Negative Side Effects of Caffeine Explained

According to the National Coffee Association, 54 percent of the general U.S. adult population drinks coffee with an average of three, 8-ounce cups per day. The U.S. Centers for Disease and Control (CDC) reported 1 in 5 Americans drink at least one soda per day. With busy schedules and coffee shops and convenience stores seemingly on every corner, there is no wonder over half the adult population adores those caffeinated beverages. Additionally, the statistics do not even attribute or mention the use and quantity of energy drinks. Every input has an output so what are the health effects of caffeine and is caffeine good or bad for you?

The Negative Impacts of Caffeine

Although caffeine can be consumed at a safe level, an excessive amount can lead to unpleasant side effects. Realistically, caffeine is a drug. In fact, caffeine dependence is now considered a mental disorder due to its addictive properties and potential for dependence. Trying to quit cold turkey can lead to painful headaches and fatigue until the body is able to adjust after a few days. Even though a morning cup of coffee helps kick start the day, it can disrupt sleep patterns when used to defeat daytime sleepiness and overcome that midday slump.

For those with acid reflux or heartburn, caffeine can exacerbate symptoms. Caffeine has the ability to relax a sphincter in the stomach. When the sphincter is closed, the acidic contents of the stomach remain in the gut and travel down the rest of the gastrointestinal (GI) tract. When the sphincter is relaxed, the stomach contents can travel upward into the esophagus and become irritating. To expand, coffee is highly acidic and can irritate the GI tract. Interestingly, research has shown switching to decaf or switching brewing methods may even increase the acid concentration in the stomach.

Additionally, side effects of extreme daily caffeine use (more than 500 to 600 milligrams per day) include irritability, anxiousness, nervousness, restlessness, and a fast heartbeat and increased blood pressure. In postmenopausal women, a high consumption can contribute to potential bone loss, especially if calcium intake is low. Caffeine can also interact with medications, limiting and/or disrupting their effectiveness.

Careful Considerations

The Mayo Clinic recommends a caffeine intake up to 400 mg per day. For pregnant women, the American Pregnancy Association says the less caffeine consumed, the better. While some experts say no more than 150 to 300 mg per day, avoiding caffeine altogether is safest or should be discussed with a healthcare provider for the healthiest choice for mom and baby. The American Academy of Pediatrics recommends adolescents consume no more than 100 mg a day and should not consume caffeinated beverages on a regular basis. Safe consumption has been linked to a reduced risk of Alzheimer's and dementia, stroke, some cancers, and type 2 diabetes.

Unless a plain, black cup of coffee, those caffeinated beverages contain more than just caffeine. That chocolaty Starbucks drink topped with whipped cream? Filled with tons of added sugar and fat. That Red Bull that gave you wings? Loaded with sugar unless noted as sugar-free. Ultimately, the intake of those high-sugar and high-fat beverages can lead to weight gain and associated comorbidities along with jitters if the cups go beyond the recommended amount.



Caffeine Intake During Pregnancy. American Pregnancy Association. Available at:

Caffeine: How much is too much? Mayo Clinic. Available at:

Sarah Asay's Photo
Written By Sarah Asay, RDN. Published on February 27, 2016. Updated on March 17, 2016.


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