A popular social media claim says drinking coffee before eating anything spikes stress hormones and damages your gut. Doctors who treat digestive conditions say the fear is mostly unfounded.
Videos circulating online have claimed that coffee on an empty stomach harms the lining that protects the gut from stomach acid, and at least one medical professional posting on TikTok warned that the habit can cause a spike in cortisol levels.
Cortisol is a steroid hormone made by the adrenal glands, which sit atop the kidneys, and it helps regulate how the body responds to stress. Both high and low levels can affect health, according to the Cleveland Clinic.
“Coffee doesn’t seem to cause major problems when you drink it on an empty stomach. Studies haven’t really shown that it causes problems [with] your cortisol or blood sugar or any other kind of metabolic issues,” said Dr. Asma Khapra, a gastroenterologist at GastroHealth in Fairfax, Virginia.
Cortisol naturally peaks in the morning anyway, the Cleveland Clinic notes, so what people interpret as a coffee-triggered spike may simply be the body’s normal daily rhythm.
What caffeine actually does to digestion
Caffeine relaxes the muscular valve between the esophagus and the stomach, according to the Cleveland Clinic. That can let stomach acid move upward into the esophagus and potentially cause heartburn.
Both regular and decaffeinated coffee trigger the release of stomach acid and gastrin, a hormone involved in digestion. That happens whether or not someone has eaten, but drinking it on an empty stomach can bring on symptoms such as nausea, burning in the abdomen or an urgent need to use the bathroom, according to Dr. Douglas Weine, a gastroenterologist based in New Jersey, who spoke with Everyday Health.
Weine also pointed out that caffeine is a stimulant that activates the central nervous system, which can raise blood pressure and heart rate and, in some people, contribute to anxiety, heart palpitations or trouble sleeping. He noted that people vary widely in how sensitive they are to caffeine.
The Cleveland Clinic confirms that the body absorbs coffee, and therefore caffeine, more quickly on an empty stomach — though many people experience no ill effects at all from drinking it that way.
Khapra said that for most people, the habit “shouldn’t really cause too many GI symptoms.”
“I think it’s fine if you enjoy your cup of coffee on an empty stomach,” Khapra said, adding the caveat that it’s best without heavy amounts of cream, milk, sugar or other additives.
