In discussing his audiobook on caffeine with Terry Gross on NPR last winter, Michael Pollan called caffeine “the enemy of good sleep” because it interferes with deep sleep. He confessed that after the challenging task of weaning himself from coffee, he “was sleeping like a teenager again.”
Dr. Willett, now 75, said, “You don’t have to get to zero consumption to minimize the impact on sleep,” but he acknowledged that a person’s sensitivity to caffeine “probably increases with age.” People also vary widely in how rapidly they metabolize caffeine, enabling some to sleep soundly after drinking caffeinated coffee at dinner while others have trouble sleeping if they have coffee at lunch. But even if you can fall asleep readily after an evening coffee, it may disrupt your ability to get adequate deep sleep, Mr. Pollan states in his forthcoming book, “This Is Your Mind on Plants.”
Dr. Willett said it’s possible to develop a degree of tolerance to caffeine’s effect on sleep. My 75-year-old brother, an inveterate imbiber of caffeinated coffee, claims it has no effect on him. However, acquiring a tolerance to caffeine could blunt its benefit if, say, you wanted it to help you stay alert and focused while driving or taking a test.
Caffeine is one of more than a thousand chemicals in coffee, not all of which are beneficial. Among others with positive effects are polyphenols and antioxidants. Polyphenols can inhibit the growth of cancer cells and lower the risk of Type 2 diabetes; antioxidants, which have anti-inflammatory effects, can counter both heart disease and cancer, the nation’s leading killers.
None of this means coffee is beneficial regardless of how it’s prepared. When brewed without a paper filter, as in French press, Norwegian boiled coffee, espresso or Turkish coffee, oily chemicals called diterpenes come through that can raise artery-damaging LDL cholesterol. However, these chemicals are virtually absent in both filtered and instant coffee. Knowing I have a cholesterol problem, I dissected a coffee pod and found a paper filter lining the plastic cup. Whew!
Also countering the potential health benefits of coffee are popular additions some people use, like cream and sweet syrups, that can convert this calorie-free beverage into a calorie-rich dessert. “All the things people put into coffee can result in a junk food with as many as 500 to 600 calories,” Dr. Willett said. A 16-ounce Starbucks Mocha Frappuccino, for example, has 51 grams of sugar, 15 grams of fat (10 of them saturated) and 370 calories.
With iced coffee season approaching, more people are likely to turn to cold-brew coffee. Now rising in popularity, cold brew counters coffee’s natural acidity and the bitterness that results when boiling water is poured over the grounds. Cold brew is made by steeping the grounds in cold water for several hours, then straining the liquid through a paper filter to remove the grounds and harmful diterpenes and keep the flavor and caffeine for you to enjoy. Cold brew can also be made with decaffeinated coffee.
Decaf is not totally without health benefits. As with caffeinated coffee, the polyphenols it contains have anti-inflammatory properties that may lower the risk of Type 2 diabetes and cancer.
