Coffee has negative effects on people with preexisting health conditions

Coffee is safe and healthy but people with pre-existing health conditions may feel more of its negative side effects like increased risk of dementia and stroke, as well as a higher risk of death from cardiovascular disease among coffee drinkers with hypertension.

And though there is “strong and consistent” evidence that moderate coffee consumption is not harmful, that does not mean coffee should be consumed for health benefits, said a member of the American Society for Nutrition, Tricia Psota, a dietitian with Nutrition on Demand. The Food and Drug Administration recommends people cap their daily caffeine intake at 400 milligrams, or about four or five 8-ounce cups of coffee. Most people are unlikely to experience serious side effects of caffeine — like erratic heartbeat, vomiting, seizures, diarrhea and even death — unless they consume about 12 cups in a day.

But even consuming 400 milligrams of caffeine daily can sometimes come with undesirable side effects, including jitteriness, anxiety and trouble sleeping, Psota said. “I’ve noticed that on days when I might not have slept as well the night before and go beyond that point, I just feel jittery and uncomfortable,” she said. “So, for me, I definitely stay below that FDA recommendation.” For pregnant or breastfeeding people, Psota recommends no more than 200 milligrams, or about two cups of coffee a day, because the caffeine can pass on to the infant through breast milk.

Some people might feel more of coffee’s negative side effects as they age, as the body’s ability to tolerate certain chemicals and foods evolves over time, said the spokesperson for the Academy of Nutrition and Dietetics, Jessica Sylvester, a dietitian at the Florida Nutrition Group. Within those milligram or cups of coffee recommendations, if you start feeling overly tired and the caffeine is not helping, then you’ve got to stop,” Sylvester said. “If your heart starts beating incredibly fast, you’ve got to stop. It’s different for each person”. Sylvester said that she has a habit of starting her mornings with a double shot of espresso in almond milk — but that over time, she has become less likely to finish the drink and often sips it into the afternoon.

Coffee can also pose risks for younger people, especially teenagers. Dr David Buchholz, a pediatrician at the Columbia University Irving Medical Center, said no amount of caffeine is healthy for adolescents. Buchholz said he wouldn’t recommend more than 100 milligrams a day, or about one 8-ounce cup of coffee, for teenagers.