Most people who drink decaffeinated coffee do so because it doesn’t make them jittery or keep them awake. But some believe it’s better for them than regular coffee—even though coffee has been cleared of nearly all health charges, and may actually be beneficial. Is decaf somehow healthier than regular coffee? Or does the decaffeination process itself represent a health risk? On the other hand, many Americans are drinking tea because they’ve heard how healthy it is. If they drink decaf tea, they may wonder, do they get the health benefits? Here are answers to these and other questions.
How much caffeine does decaf contain?
It must have at least 97 percent of the caffeine removed. That leaves about 5 milligrams, compared to the 100 to 150 milligrams in 6 ounces of brewed coffee. Tea starts with much less caffeine, so most decaf tea has even less caffeine than decaf coffee.
How is coffee or tea decaffeinated?
There are three methods to extract the caffeine: using organic chemical solvents (methylene chloride or ethyl acetate), carbon dioxide or the water method (also known as the Swiss Water method). Since ethyl acetate is derived from fruit, coffee de-caffeinated via this solvent is sometimes described as "natural" decaf. Some coffee or tea processors use different methods for their various products.
Is one type of decaf preferable?
No. Over the years there have been worries about decaf processed with methylene chloride because studies had found that this chemical caused cancer when inhaled by lab animals (which is why it was banned in hair sprays). But there was no carcinogenic effect when the animals drank the chemical. In any case, the residue in decaf is virtually nil, and there’s no evidence of any danger for humans drinking decaf. The Food and Drug Administration (FDA) has approved the compound for use in decaffeination. Many companies, including Starbucks, use methylene chloride because consumers tend to prefer the taste compared to, say, water-filtered decaf, which usually tastes blander.
Does regular coffee pose any health risks?
Coffee has been blamed for causing many ailments, but in nearly every instance it has been declared not guilty, as we have reported over the years. It was linked to heart disease and pancreatic cancer—but then exonerated. Some researchers still worry that coffee drinking may promote hypertension; most studies, however, have found no such effect. A few studies have suggested that large quantities of coffee (regular or decaf) can boost blood cholesterol slightly, but most research has found no increase in cholesterol or cardiovascular risk. One exception: drinking five or more cups of unfiltered coffee, brewed in a French press (a pot with a plunger), raises cholesterol.
Caffeine actually has potential benefits. Besides boosting alertness, it has an analgesic effect, which is why it is added to some pain relievers. Several studies also suggest it helps prevent Parkinson’s disease. A review of 18 studies, published in the Archives of Internal Medicine, suggested that high intakes of regular and decaf coffee, along with tea, may reduce the risks of Type 2 diabetes. And there’s evidence suggesting it may help against gallstones and dental cavities.
What about decaf—does it pose any risks?
Though decaf has been less studied than regular coffee, it too has been the focus of several health scares that have so far not panned out. For instance, a study of women in Iowa found that those drinking four or more cups a day of decaf had an elevated risk of rheumatoid arthritis, but another study, from Harvard, found no such link.
Decaf can, however, have some of the same effects on the body as regular coffee. It too can cause heartburn or irritate stomach ulcers in susceptible people. And oddly enough, even without the caffeine, it too can stimulate the nervous system and briefly boost blood pressure in those unaccustomed to coffee, according to Swiss researchers. But coffee, decaf or regular, does not cause hypertension.
Is decaffeinated tea as healthful as regular?
No one knows. The studies suggesting health benefits have looked at people who drink a lot of regular tea, not decaf. The benefits apparently come from antioxidant compounds called flavonoids. Decaf tea generally contains less of these, though flavonoid content varies widely among teas, so it is hard to predict. The levels also depend on how the tea was processed. Moreover, not all types of flavonoids are lower in decaf tea, and it’s not known which ones are most important. A few studies suggest that decaffeinated teas do have potential anti-cancer effects. For instance, one study found that smokers who drank four cups of decaffeinated green tea daily for four months had significantly reduced DNA damage, as shown by urine tests. Another study gauged the total antioxidant capacity of various teas and found that some decafs rank higher than some regular teas.
On the horizon: Researchers are now working on breeding coffee plants that will have up to 98 percent less caffeine. But making these plants commercially viable looks like it will take years.
Originally published May 2008. Updated April 2013.