I read my first study about 20 years ago: The research suggested coffee could be healthy. For me, the norm after drinking coffee was sweaty palms, the jitters and pumping my leg like a sewing needle under my desk. Sometimes, if I kept sipping my "joe" into the afternoon hours, a sickly quivering sensation would creep into my core. How could that be healthy?
Yet, it's true. There are thousands of studies on the benefits of coffee. A simple search returns more than 30,300 journal articles on coffee. That shouldn’t be surprising for a drink that’s been around for thousands of years.
Early days of research
One of the early published articles on caffeine was by Argyll Robertson, M.D., an eye surgeon at the Edinburgh Royal Infirmary in Scotland. The article, published Jan. 3, 1885, in the British Medical Journal, described how the doctor tested the merits of caffeine as a local anesthetic on a patient’s eyes.
Dr. Robertson wrote: “The expense of cucaine [sic] is so great, that it is very desirable that some other less expensive substance should be found which acts as powerfully as a local anaesthetic [sic]. Caffeine, which is known to resemble cucaine in chemical constitution, and to some extent in therapeutic properties, naturally suggested itself to many as a possible substitute.”
Caffeine eye drops weren’t the answer, although they did cause pupil dilation in patients that lasted about 24 hours.
Perhaps Dr. Robertson would be heartened to know that in 2010 researchers at the University of Maryland reported in the journal Molecular Vision that caffeine eye drops may "significantly inhibit the onset as well as the progress of cataract formation,"
Positive and negative effects
In January 2017, Stanford University researchers published an article that suggests coffee drinkers might live longer. In this early study, researchers aren’t saying that coffee flows from the Fountain of Youth, but at a molecular level, caffeine may dampen the inflammatory process involved in heart disease in some patients later in life.
There are plenty of studies about the negative effects of too much coffee, as well. Side effects of large doses of caffeine include dizziness, dehydration and abnormal heart rhythms. Therefore, prescribing coffee isn’t likely to be recommended by the American Academy of Family Medicine.
But there’s no need for that. Coffee and tea are the most consumed beverages in the world after water. In the U.S., we consume an average of 2.1 coffee drinks per day, and the number increases as we age, according to a recent Zagat survey.
What’s so special about caffeine?
Here are a few basic facts about caffeine, the most active compound among many in coffee:
- It's an antioxidant. Caffeine stops a chain reaction by free radical molecules that results in damage to healthy cells.
- It’s anti-inflammatory. Caffeine blocks receptors in the brain that cause inflammation when they’re triggered.
- It prevents apoptosis, a different type of cell death involved in some diseases that begin at the genetic level.
Because of these and other abilities, caffeine has been proven to be beneficial in men with Parkinson's disease, and in men and women with Alzheimer’s disease. Caffeine has shown benefits in people with heart disease, stroke and Type 2 diabetes.
Recommended amount
Keeping it to three 8-ounce cups a day is probably a good idea. That’s about the high dose used in many studies showing the benefits of coffee. If you need more proof that it’s enough, take my word for it. I participated in the jittery leg trial.
Want to learn more about coffee and caffeine, and find more studies? The U.S. National Libraries of Medicine is a good place to start. It includes a page on clinical trials testing the drug's effects. Be sure to talk to your provider if you have questions about how much coffee you drink.
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