Molecular medicine specialist

Caffeine has been shown to improve focus and memory. It can even help with athletic performance and with overcoming fatigue from exercise. However, people's reaction to it varies. Some people are supersensitive and feel edgy after just a few sips of coffee, while other people may feel no reaction. People can also build up a tolerance and become increasingly dependent on caffeine. You really have to listen to your body to know what is a safe amount for you. Rapid heart rate, palpitations, and feeling edgy, tense, or dizzy are typical signs you've had too much. Most people can safely drink a couple of cups of coffee a day.

If you need caffeine to stay alert and to function, then there's an underlying biochemical reason. Are you getting enough sleep? Are you exercising? How's your diet? If symptoms persist after you've made an honest effort to change, then it's time to see your doctor.

Cut back on caffeine slowly to avoid withdrawal symptoms, including the “rebound headache.” Try drinking some noncaffeinated herbal tea with honey. It is not always obvious that a food or beverage product contains caffeine, so read food labels carefully. Synephrine (Citrus aurantium) and guarana are other ingredients, found in energy drinks and weight-loss and fat-burning supplements, that can produce similar effects to caffeine.

—Dale Guyer, MD, The Guyer Institute of Molecular Medicine, Indianapolis, Indiana; co-author of Getting Well (Author House, 2004)

Detoxification specialist

Caffeine isn't necessarily harmful if you have a healthy relationship with it. In other words, you should be able to easily take a break from daily use and be fine. If you're consuming more than 500 mg of caffeine a day, then a break could be a good idea. Drinking caffeine may energize you, but it may be just a Band-Aid for an underlying ailment. For instance, caffeine helps some people stay regular. But a good diet, water, and fiber from fruits, vegetables, and whole grains carry the same benefit and make for a healthier lifestyle.

Caffeine is an addictive drug, so cutting back gradually will make withdrawal symptoms much easier to handle. Because caffeine is acidic, a more alkaline diet can help minimize withdrawal. That means eating more fruits and vegetables, and less bread, cheese, and meat. Extra vitamin C (500-1,000 mg two or three times a day) and vitamin B complex (25-50 mg per day) may help. If you feel tense, a calcium-magnesium combination (300-500 mg each before bed) can help you relax. Magnesium is a mild laxative, which will help with constipation — a side effect of cutting back on caffeine for some people.

Also, look at what you're eating and drinking. Caffeine may be found in many products — especially foods that are coffee or chocolate flavored, such as yogurt, ice cream, energy bars, and cookies. Even some over-the-counter medicines like Excedrin, Midol, and Dristan can contain caffeine.

—Elson M. Haas, MD, Preventive Medical Center of Marin, San Rafael, Calif.


Coffee may not be as bad as we once thought, possibly because it contains more antioxidants, such as quinides, than other beverages. Quinides are produced during the roasting process and may partly offset caffeine's potentially negative effects, such as jitteriness and anxiety.

Coffee, both caffeinated and decaffeinated, has been found to lower the risk of liver cancer and type 2 diabetes. And caffeinated coffee might give men and women some protection from gallstones. There is some evidence that coffee also lowers the risk of Parkinson's disease, but researchers don't know yet whether that's due to caffeine or to other compounds.

Tolerance to caffeine is very individualized, but most people don't need to worry about those one or two cups of coffee a day. Even if you're an espresso fan, you can relax. Although espresso packs about four times more caffeine per ounce than regular coffee, the typical serving size is just 1 ounce. So even three espressos can have less caffeine than a typical 12-ounce cup of coffee.

However, if you're working to control your cholesterol, you may want to avoid espresso because it does contain small amounts of cafestol, which is known to raise blood cholesterol. Pregnant women should also limit their caffeine because some studies indicate that high caffeine intake during pregnancy may lower birth weight.

—Rob M. van Dam, PhD, assistant professor of nutrition, Harvard School of Public Health, Boston

Caffeine levels in common beverages

Drinks (12oz) Caffeine (mg)
Drip coffee 240-300
Black tea 100-120
Espresso (1oz) 75
Green tea 60
Mountain Dew 50
Cola 30-65
Chocolate milk 20-30
Decaf coffee 6-20
Source: Staying Healthy with Nutrition (Celestial Arts, 2006) by Elson M. Haas, MD