What are the negative effects of caffeine?

Caffeine has it's pros and cons.  But as with most things in life, too much of something isn't good for you.  Caffeine is a chemical compound found in various plants that acts as a central nervous system stimulant.  It is known to produce physical dependence and to alter moods. 

The negative effects of caffeine:

  • nervousness
  • insomnia
  • restlessness
  • irritability
  • accelerated heartbeat
  • stomach upset
  • frequent urination
  • anxiety
  • muscle tremors
  • headaches
  • irritability
  • jitteriness

It's recommended that adult consumption be between 300-400 mg (that's equivalent to 3-4 cups of coffee) and teens be around 100 mg.

Joel H. Fuhrman, MD
Family Medicine
In addition to the slightly increased risk of osteoporosis or heart disease, there are other problems with caffeine. Caffeine is a stimulant, so it gives you the false sensation that you can comfortably get by on less sleep, and inadequate sleep promotes disease and premature aging. Overall, it is difficult to discern the precise risks from heavy coffee drinking because most people who drink lots of coffee participate in lots of other unhealthy behaviors as well.

My main objection to drinking coffee is that it is addicting and, therefore, may promote more frequent eating and a higher calorie intake in some people. Eliminating your caffeine intake may help you lose weight. Coffee drinkers -- and tea and cola drinkers -- are drawn to eat more frequently than necessary. They eat extra meals and snacks because they mistake unpleasant caffeine withdrawal symptoms with hunger. They can't tell the difference between true hunger and the discomfort that accompanies caffeine withdrawal.

In essence, coffee is mostly like a drug, not a food. In spite of the presence of some beneficial antioxidants, it also has some negative effects and withdrawal symptoms that may fuel drinking and eating behavior. Like most drugs, it could have some minor benefits, but its toxic effects and resultant risks likely overwhelm those minor advantages.
Eat for Health: Lose Weight, Keep It Off, Look Younger, Live Longer (2 Volume Set)

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Eat for Health: Lose Weight, Keep It Off, Look Younger, Live Longer (2 Volume Set)

Dr. Fuhrman's scientifically proven system, Eat For Health, enables you to finally conquer your cravings and food addictions, while steering your taste buds toward healthier food choices. Medical...
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Caffeine can cause you to have a premature baby.

Watch the video to learn more from Dr. Oz about the negative side effects of caffeine.


When taken in appropriate doses (used in moderation) caffeine is considered to be a relatively safe substance (by the FDA). Negative effects occur when an overdosage occurs. Overdosage is different for each individual and is usually based on age, weight and caffeine tolerance. Overdosage will result in: nervousness, irritability, anxiety, rambling thoughts or speech, fidgetiness, excitement, euphoria, flushing of the face, shaking hands and feet  tremors), muscle twitching, insomnia, headaches, and heart palpitations.
Discovery Health
Administration
Along with its ability to ward off drowsiness, caffeine also increases dopamine levels the same way amphetamines do. Dopamine, a neurotransmitter, activates pleasure centers in certain parts of the brain. Cocaine and heroin also manipulate dopamine levels. They do this by slowing the rate of dopamine reabsorption. Caffeine's effect, obviously, is much lower than cocaine's, but it is the same mechanism. Scientists suspect the dopamine connection contributes to caffeine addiction.

It's obvious why your body likes caffeine in the short term, this is especially true if you're low on sleep and need to remain active. It blocks adenosine reception, making you feel alert. It stimulates adrenaline production to give you a boost. It also manipulates dopamine production to make you feel good.

Unfortunately, caffeine's longer-term effects tend to spiral. Once the adrenaline wears off, for example, you face fatigue and depression. To combat this, you consume more caffeine and get that adrenaline going again. But remaining in a state of emergency all day isn't very healthy. It also makes you jumpy and irritable.

Caffeine's most important long-term problem is the effect on sleep. The half-life of caffeine is about six hours. If you gulp down a big cup of coffee (with its 200 mg of caffeine) at 3 p.m., by 9 p.m. about 100 mg is still in your system. If you can fall asleep, your body probably will miss out on the benefits of deep sleep. The lack of deep sleep adds up fast. The next day, when you feel worse, you crave caffeine as soon as you get out of bed. Day after day, that cycle continues.

Now, 90 percent of Americans consume caffeine every day. They get in the cycle, and have to keep consuming the drug. What's worse: if they stop consuming caffeine, they get very tired and depressed, and get a terrible, splitting headache from the blood vessels in the brain dilating. These negative effects can force you to run for more coffee even if you want to stop.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.