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March 12, 2011

Is caffeine actually good or bad for you?

Each week a nutritionist from the University of Maryland Medical Center will provide a post on nutrition topics. Have questions or ideas for future topics? Email This week, Shanti Lewis, RD, CNSD, CSP, weighs in on caffeine.   

Consumers are often confused about caffeine since they may have heard or read news reports on research that associates caffeine to cancer, heart palpitations or osteoporsosis. However, no study has found a significant link between cancer and caffeine consumption. Moderate consumption of caffeine is safe for most healthy individuals, and some beverages that contain caffeine have been shown to have potential health benefits.

Is caffeine bad for me?

For most healthy individuals, moderate caffeine consumption at 300 milligrams per day (about 3 cups of coffee) is considered safe. Studies have demonstrated no correlation between caffeine consumption and heart disease mortality or incidence, but people with high blood pressure or heart valve disease may want to consider limiting their intake.

Although not directly related to caffeine, unfiltered coffee has been shown to raise total cholesterol levels with the most significant elevation in triglycerides and low-density lipoprotein (LDL) cholesterol. The elevation in total cholesterol results from a substance called cafestol, which is primarily found in French-press coffee and Turkish coffee. Studies suggest that limiting unfiltered coffee consumption to 6 cups per day may be beneficial to avoid elevations in cholesterol levels.

Individuals with reactions to methylxanthine compounds should avoid any food or beverage that contains caffeine. People with this reaction may experience panic attacks, vomiting, heart palpitations and headaches.

What are the side effects of caffeine consumption?

Every individual has a different tolerance to caffeine. Some people may feel jittery or over energized with a single cup of coffee.

If someone has irritable bowel or reflux, caffeine may lead to worsening symptoms. Studies suggest that there may be a correlation between coffee consumption and lower bone density; however, an adequate consumption of calcium-rich foods and beverages should counteract this effect.

Are there benefits to consuming caffeine?

Caffeine does increase alertness and has been found to help end asthma attacks by constricting bronchial muscles. Individuals who consume caffeine or coffee regularly have a decreased risk of developing Parkinson’s disease.

Certain beverages, like coffee or tea, contain antioxidants that may protect individuals from developing diabetes, cancer or heart disease.


Does caffeine help with weight loss?

Some studies suggest that drinking coffee or tea may slightly boost weight loss or help with weight maintenance by causing appetite suppression or increasing thermogenesis, but the jury is still out.

Caffeine does have negative side effects, such as jitteriness or insomnia. In order to lose weight, it is critical to reduce overall caloric intake and increase physical activity rather than rely on caffeine consumption.

Is it safe to consume caffeine if pregnant or lactating?

Caffeine consumption has been linked to miscarriages in the first trimester. It may be beneficial to limit caffeine intake during the second and third trimesters, even though no specific recommendations are published.

If a mom is breastfeeding, her milk will contain caffeine if she consumes it. Some babies experience irritability and insomnia as a result of receiving caffeine in breast milk. Moms who consume more than one or two cups of coffee per day may reduce the bioavailability of iron in their breast milk.

Does caffeine improve athletic performance?

Most studies on caffeine and athletic performance found that caffeine does enhance performance and makes the effort seem easier for endurance activities and short, high-intensity activities. A moderate amount of caffeine intake is 250-300 mg/day.

Research shows that the amount of caffeine needed to enhance performance is 1.5 to 4 mg/lb body weight taken an hour before exercise. Any amount above this level has not been shown to improve performance.

Athletes have varied responses to caffeine. Some athletes are very sensitive to caffeine and need to limit consumption to avoid negative side-effects. Other athletes can consume a large amount of caffeine without any side effects. It is important to remember to do trial and error to determine the right amount of caffeine for your body.

A study at the University of Buffalo found that gender may play a difference on caffeine’s effect on the body. Males were found to feel a greater rush and have more energy or athletic performance than females.

How much coffee am I consuming?

6-fl-oz drip coffee: 100 mg

6-fl-oz brewed tea: 50 mg

12 –fl-oz of regular soda: 35-50 mg

1 fl-oz of espresso: 40 mg

1 –oz dark chocolate: 30 mg

6-fl-oz decaffeinated coffee: 2 mg

1- oz Gu (electrolyte tablet): 20 mg

1 piece Jolt gum: 40 mg

8-fl-oz energy drink: 80 mg

1 tablet caffeine pill: 200 mg

How to cut back on caffeine

Since caffeine can be addictive, it is important to wean slowly from caffeine to avoid withdrawal symptoms. It is important to start weaning off caffeine beverages by mixing them with decaffeinated varieties to avoid headaches and irritability.

What is the bottom line?

Everyone has an individualized tolerance to caffeine intake. When choosing caffeinated beverages, it is best to aim for those that are not energy-dense. It is best avoid regular soda and coffee drinks with added cream and sugar, but choose diet sodas and coffee with skim or low fat milk with a sweetener.


Clark, N.  The facts about caffeine and athletic performance. Retrieved on
March 1, 2011 from

Lopez-Garcia E, van Dam RM, Li TY, Rodriguez-Artalejo F, Hu FB. (2008). The Relationship of Coffee Consumption with Mortality. Ann Intern Med., 148:904-914
Temple, JL, Dewey, AM, Briatico, LN.  (2010). Effects of acute caffeine administration on adolescents. Experimental and Clinical Psychopharmacology, 18(6), 510-520.

Posted by Kim Walker at 7:35 AM | | Comments (3)
Categories: Nutrition


Some of the information on this page is good. But, nevertheless, much of it is misinformed. For example, advising people to keep their dose of caffeine down to 300mg is just plain irresponsible. Each person has a different tolerence level and capacity to benefit from caffeine. Also the advice on athletics is only half-true. I suggest interested parties check out to get the latest accurate information about caffeine.

One additional correction: Caffeine is not addictive. Even we called it "addictive" in our book The World of Caffeine. But we were contacted by so many medical and pharmacological experts to correct us that we changed our tune in our future books. Caffeine creates a metabolic dependency. That means you should not stop using it suddenly, but, rather, taper off. But no one has ever lost his wife, his house, or his job because of caffeine. Addictive drugs are drugs, like heroin and cocaine, that can do these things.

oh so addiction depends on sociological effects? how does metabolic dependency =/= addiction? And alcoholics and heroin addicts are also advised not to "stop using it suddenly." My grandfather lost his house, wife, and job, in that order because of caffeine.

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Andrea Siegel, a reporter at The Baltimore Sun, covers mostly crime and courts in Annapolis and Anne Arundel County, as well as legal issues. She wishes she was more physically fit, and, as she's more fond of chocolate than exercise, fitness is a challenge. Her partner on a one-mile-plus daily walk is the family dog, a mixed breed named Moxie, and she exercises at the gym where the D.C. snipers once worked out.
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