Q: I love coffee! I drink three cups a day. Is this harmful?
A: Probably not. Based on many studies, which I read as I sip my own brew, three cups is a reasonable amount.
In fact, there are many positive effects from coffee and its primary ingredient, caffeine (the most recent being a report from Japan that daily coffee drinking cuts the risk of liver cancer in half).
First, though, a caveat: The reason I say “probably” is that some medical conditions mean coffee is not for everyone. (Please below for several potential issues.)
Some quick coffee factsCaffeine is a psychostimulant that occurs naturally in coffee beans. It is also present in tea and chocolate (though in smaller quantities) and is used in many sodas.
Just so you know what’s in that cup:
- An average cuppa Joe has 135 mg of caffeine
- Instant coffee: 95 mg
- Shot of Espresso: 50 mg
- Decaf: 3 mg
Incidentally, if you want to lessen the effects of coffee consumption, you might want to drink coffee made from the Arabica bean, which has about half the amount of caffeine as the Robusta bean, the other main variety.
The good things about coffee
- Caffeine promotes wakefulness, improves thinking and enhances mood, even in small doses. It also improves muscle coordination and strength, especially if you drink it just before exercise. In addition, it increases energy expenditure, helping you burn calories.
- We also know that caffeine can relax the airways, helping decrease asthma attacks. And it acts as a laxative — good for those with constipation.
- Studies show that men who drink 2 to 3 cups of coffee daily have fewer gallstones than others. And, at least in Japanese-American men, coffee drinkers have a lower incidence of Parkinson’s disease.
The not-so-good things
- Like nicotine (and many other psychostimulants) caffeine is addictive. It increases levels of dopamine, which acts as a reward system in the brain. So once you start drinking it regularly, you are likely to get coffee cravings, which can result from consumption as low as a cup a day. If you try to stop cold turkey, you may experience withdrawal symptoms that include headache, fatigue, irritability, depression and even flu-like symptoms. These can last up to two weeks. (Caffeine withdrawal, by the way, is why pre-operative patients, who cannot eat or drink before surgery, get headaches. We now let them have coffee as soon as they can tolerate fluids.)
- Because caffeine perks you up, a late-day cup can make you wakeful at night. It takes up to seven hours to metabolize caffeine — more if you take estrogen or birth-control pills.
- Excessive coffee can make you anxious and jittery. If you suffer from anxiety or panic attacks, even small amounts of caffeine can exacerbate these conditions.
- Coffee, even decaffeinated coffee, can increase production of stomach acid and prevent proper closure of the valve between the stomach and esophagus. So if you have heartburn or reflux, coffee is not the beverage for you. The same goes for incontinence — coffee’s diuretic effect may make bathroom emergencies worse.
- It can make pain medications for headaches more effective, but chronic use can cause so-called “rebound” headaches. Over-the-counter medications containing caffeine — Anacin and Excedrin are well-known examples — should be used only for a few days at a time.
The bad things
Matters become more acute when coffee is drunk in conjunction with various medical conditions and/or in excess. Here are several examples:
- You should seriously consider your level of caffeine consumption if you are trying to get pregnant. Research shows that women who drink more than 2.5 cups a day may double their infertility rates.
- For women who have become pregnant, there may be a 30 percent increase in miscarriage rates in women who drink one to two cups a day, rising to 40 percent with consumption of four cups a day. We don’t know why this happens, but we do know that pregnant women metabolize caffeine more slowly than their non-pregnant cohorts.
- More than five cups a day increases fibrocystic changes in the breast, making them lumpy and painful.
- Too much coffee also blocks the absorption of some vitamins and minerals, especially calcium. Since coffee acts as a diuretic and calcium is secreted in the urine, it seems that over-consumption boosts the risk of osteoporosis. There is no conclusive link; however, adolescents should not consume caffeinated drinks instead of milk — they will be lacking the calcium they need at this crucial bone-building time.
- For people with heart disease, caffeine can cause palpitations and heartbeat irregularities.
Dr. Reichman’s Bottom Line: If you enjoy coffee and have no health reasons for abstaining, keep sipping — in moderation.
Dr. Judith Reichman, the “Today” show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," published by William Morrow, a division of .
PLEASE NOTE: The information in this column should not be construed as providing specific medical advice, but rather to offer readers information to better understand their lives and health. It is not intended to provide an alternative to professional treatment or to replace the services of a physician.