You probably know that tea and coffee contain caffeine, but did you know it also can be found in other drinks, food and some medications? When it comes to caffeine consumption, you're not alone if you depend on it to help you concentrate or be alert. Studies have shown that about 90% of U.S. adults consume a form of caffeine every day.

How much caffeine is too much?

Caffeine content in beverages widely varies. For most adults, consuming up to 400 milligrams of caffeine daily does not have adverse side effects. Depending on the type of beverage, that can be roughly four cups of brewed coffee, 10 cans of cola or two energy shot drinks.

While consuming some caffeine is OK, too much can cause side effects, including:

• Fast heartbeat
• Headaches
• High blood pressure
• Insomnia
• Muscle tremors

Adolescents and young adults must be cautious when drinking caffeine, and children should avoid it altogether. People who are sensitive to caffeine's effects or take certain medications should avoid consuming too much caffeine. People who are pregnant, want to become pregnant or are breastfeeding should talk with their healthcare team about caffeine consumption.

Common caffeine sources

If you reach for different types of beverages throughout the day, you may be drinking more caffeine than you realize. With a cup of coffee or tea with breakfast, a soda in the afternoon and a piece of chocolate after supper, caffeine is part of your daily eating habits.

Some of the most common sources of caffeine are:

• Chocolate
• Coffee
• Medication
• Soda
• Tea

Caffeine also can hide under some names that are less recognizable. Energy drinks have additives that contain caffeine to enhance the effects of the drink. Knowing about these additives can help you avoid consuming more caffeine than you thought, so be sure to check labels before you buy.

Some common additives that contain caffeine include:

• Cartinine
• Choline
• Ginseng
• Glucuronolactone
• Guarana
• Inosol
• Kola nut
• Malic acid
• Maltodextrin
• Niacin
• Pantothenic acid
• Taurine
• Theanine
• Tyrosine
• Yerba mate

Caffeine in powder or liquid form can be particularly dangerous. The Food and Drug Administration has warned that high levels of caffeine can cause serious health problems. One teaspoon of powdered caffeine is the same as drinking 28 cups of coffee, which is significantly more than the recommended level.

Kicking a caffeine habit

If caffeine becomes more of a hindrance than a help, you may want to consider cutting back. This can be challenging because an abrupt decrease can cause withdrawal symptoms like headaches, fatigue and difficulty focusing.

To lessen caffeine withdrawal symptoms, try these tips:

• Be aware of and track how much caffeine you consume throughout the day.
• Cut back gradually so your body gets used to lower levels of caffeine.
• Check products you use for caffeine, such as over-the-counter pain relievers.
• Shorten the brew time of tea to cut down on the caffeine content, or choose an herbal tea that doesn't have caffeine.
• Switch to decaffeinated beverages, which have a similar taste but much less caffeine than their full-strength counterparts.

Contact your primary care provider for guidance or evaluation if you're struggling with persistent or severe caffeine withdrawal symptoms.

Brian Burroughs is a physician assistant in Family Medicine with special interest in headache treatment, in Red Wing, Minnesota.

This article first published on the Mayo Clinic Health System blog.

Related resources

• Mayo Clinic Q and A: Caffeine’s effects on blood sugar and blood pressure
• Does caffeine make depression worse?
• Mayo Clinic Minute: Kids and Caffeine

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