by Michael Nickels, M.D.
Many years ago a series of television ads appeared in
which successful individuals were identified as "Coffee Achievers." I related
strongly to these ads, as much of my own success in life has been achieved in a
highly caffeinated state. I am certainly not alone in this regard, as over half
the U.S. population drinks at least two cups of coffee a day. Furthermore, since
caffeine is also found in tea, chocolate, many over-the-counter cold
medications, and a majority of soft drinks, this substance has grown in
popularity to become the most commonly used drug in the world. In fact, it is
the rare individual who does not consume at least some caffeine on a daily
basis. With this in mind, it is highly prudent to ask the question, "What effect
does caffeine have on our health?"
Caffeine is a central nervous system stimulant that in moderate doses reduces drowsiness, increases concentration, improves mood and shortens reaction time. Tolerance will develop with consistent use, requiring larger doses to get the same stimulant effect. If their daily intake is suddenly curtailed, moderate to heavy users (more than 3 – 4 cups a day) will often develop withdrawal symptoms—headache, irritability or increased fatigue. In large amounts, caffeine may cause anxiety, nervousness, irritability, restlessness, headaches, tremors, nausea, and ringing in the ears. It is possible to die from an oral caffeine overdose; however, it would require from 50 to 200 cups of coffee or approximately 50 Vivarin (200mg) caffeine tablets to do so.
Many researchers have attempted to correlate caffeine or coffee with adverse health effects. During the 1960’s and 1970’s, research studies indicated that caffeine may increase the risk of developing a number of pathologies, including heart disease, cancer, birth defects, and fibrocystic breast disease. More recent studies have attempted to use better controls and separate out factors that effect our health. When factors such as diet, cigarette smoking, lack of exercise, and heavy alcohol use are taken into account, little evidence can be found linking low to moderate caffeine consumption with adverse health consequences. In fact, just the opposite is true, as several recent studies suggest caffeine reduces the risk of developing gallstones, colorectal cancer and depression.
Clearly, much work remains in clarifying the affect of caffeine consumption on our health. In general, however, caffeine is considered to be a "safe" drug when consumed in low to moderate amounts. The following is a short list of health problems with which coffee has been associated:
1. Coronary Artery Disease: this has been one of the most controversial areas in caffeine health research. In the past, caffeine has been linked to an increased risk for developing coronary artery disease and myocardial infarctions (heart attacks). This association may be secondary to increases in blood pressure and serum cholesterol, both of which have been found to be higher in individuals who consume coffee. Most recent data, however, has not found any evidence that mild to moderate caffeine use (2 – 6 cups per day) increases blood pressure, cholesterol, or coronary artery disease.
2. Cardiac Arrhythmias: caffeine will intensify certain irregular heartbeats in susceptible individuals. Generally, if you know you have a history of irregular heartbeats, my advice is to avoid stimulants of any kind.
3. Cancer: numerous studies have attempted to correlate caffeine or coffee with various forms of cancer. In the 1970’s, for example, several studies indicated that caffeine might increase the risk of bladder and pancreatic cancer. While it is true that researchers were able to induce cancer in several animal models, the doses used were often 20 to 40 times higher than that consumed by even the heaviest of coffee drinkers. Current research does not indicate an association exists between caffeine and increased cancer risk. In fact, some researchers are finding that caffeine / coffee may provide a protective effect. An example of this is a recent finding that individuals who drank 4 or more cups of coffee a day, were 24% less likely to develop colorectal cancer. Much research is still required in this area. For the moment at least, it appears that caffeine use does not significantly increase your cancer risk.
4. Gastrointestinal Disease: caffeine is known to relax the band of muscles separating the esophagus from the stomach. This action increases the reflux of stomach acids into the esophagus in susceptible individuals and produces "heartburn." Caffeine will also increase the production of stomach acids, thereby irritating any ulcers that might be present. Interestingly, coffee may also play a protective role in suppressing the development of gallstones, as a recent study found that men who drink coffee have a 30% to 50% decreased risk for their formation.
5. Osteoporosis: caffeine has been associated with increased excretion of calcium in the urine. Current studies indicate that one would have to drink very large volumes of coffee to observe any decrease in bone density. It is estimated that a glass of milk per day will offset the loss of calcium secondary to the diuretic effect of caffeine.
6. Fibrocystic Breast Disease: a study in the early 1980’s found that caffeine increased a woman’s risk for developing fibrocystic breast disease. Further research has not substantiated this finding, although many medical professionals continue to advise women with fibrocystic changes to avoid caffeine.
7. Pregnancy: the U.S. Food and Drug Administration regards moderate caffeine intake to generally be safe, but advises pregnant women to reduce or curtail their caffeine consumption. This is due to several human and animal studies in the 1970’s and 1980’s that linked caffeine to birth defects, low birth weight, miscarriages and stillbirths. Again, these animal studies have often used abnormally high caffeine blood levels and the human studies fail to show a strong correlation when other adverse health factors are taken into account. Most recent studies tend to show little harm in mild caffeine consumption; however, when carrying a child it is always best to "live clean," avoiding all potentially harmful substances such as alcohol, tobacco, unnecessary medication and caffeine.
In conclusion, I thought I would share some interesting trivia I gathered while researching this article.
• Amount of caffeine in various foods, drinks or pills: Vivarin caffeine pill has 200 mg; automatic drip coffee (7 oz) has 115 to 175 mg; cup of espresso has 100 mg, Jolt Cola has 71.2 mg; Sugar-Free Mr. Pibb has 58.8; Mountain Dew has 55.0 mg; Coca-Cola has 45.6 mg; Mr. Pibb has 40.8 mg; Pepsi Cola has 37.2 mg; Iced Tea (12 oz) has 70 mg; Chocolate Bar (average) has 10 to 30 mg, Decongestant with caffeine has 30 mg; Decaffeinated coffee has 2 mg.
• Legend has it that coffee was discovered by an Arab goat herder named Kaidi, who noticed his charges became frisky and danced around the fields after eating berries from certain wild bushes. He apparently tried a few himself and soon became as hyperactive as his heard.
• The first drink made from the coffee tree was a wine distilled from a mixture of coffee, cherries, water and honey. This wine was highly prized within the Arab world.
• A Turkish law passed in 1475 made it legal for a woman to divorce her husband if he failed to provide her with her "daily quota of coffee."
• Pope Vincent III considered banishing coffee from the Christian world after hearing it referred to as the "Devil’s Drink." Fortunately, he decided to try coffee before condemning it. He enjoyed the brew so much that he instead baptized it, saying, "Coffee is so delicious that it would be a pity to let the infidels have exclusive use of it."
• Admiral Josephus "Joe" Daniels, Chief of Naval Operations, outlawed alcohol onboard ships of the United States Navy, replacing it with coffee. This beverage became known as a "Cup of Joe." Since sailors were often cold and wet, they preferred to drink their coffee hot. Thus the name was shortened to "Hot Joe," then "Hojo."
Michael Nickels received an M.D. and a Ph.D. in Biomedical Science (Microbiology and Immunology) from the University of South Carolina School of Medicine.