Exactly How Much Coffee Should You Drink a Day to Lower Your Risk for IBS?

Fact checked by Nick Blackmer

Key Takeaways

• A recent study found that drinking instant or ground coffee at higher rates was associated with a lower risk of irritable bowel syndrome (IBS), especially for those who drank four or more cups a day.

• But for some people with IBS, coffee is one of many dietary triggers that can set off stomach cramping or diarrhea.

Between 25 and 45 million people in the United States have irritable bowel syndrome (IBS), a condition known for various digestive issues. While introducing a stimulant like coffee may not seem like a way to stave off IBS, new research suggests that drinking coffee every day may be associated with a lower risk of developing the condition.

The research, published in the International Journal of Epidemiology in March, considered people who did not have IBS at the start of the study and followed them for an average of 12 years. Those who drank the most coffee—four or more cups a day, according to an intake survey—had a significantly lower risk of developing the digestive disorder compared to caffeine abstainers.

Drinking coffee can keep things moving through the digestive tract, but there's not enough evidence for dietary guidelines to recommend four cups a day to reduce IBS risk. For folks with IBS-D, or diarrhea-type IBS, that much caffeine may seem like a recipe for disaster.

On the other hand, many individuals who struggle with constipation depend on a daily cup of joe to stay regular, according to Jeffrey Crespin, MD, a gastroenterologist and a clinical assistant professor at New York University.

“Coffee is a great laxative,” Crespin said. “That can be really helpful for a lot of patients, especially those with constipation-predominant IBS.”

That’s because drinking coffee stimulates the release of gastrin, a hormone that causes the intestines to constrict and relax, Crespin said. A second hormone found in coffee, called “cholecystokinin,” helps with digestion by triggering bile production.

IBS has three distinct subtypes: diarrhea-type (IBS-D), constipation-type (IBS-C), and mixed-type IBS (IBS-M). These subtypes are based on symptom groups and can help guide healthcare providers’ recommendations on diet and IBS management.

The American College of Gastroenterology recommends changing your diet and lifestyle as a first-line approach for managing IBS. There's no known cure or single cause of IBS, so healthcare providers may suggest following an elimination diet to identify or rule out trigger foods. Foods commonly triggering IBS include dairy, corn, soy, gluten, and cruciferous vegetables such as broccoli and cabbage—but remember, everyone’s gut responds differently.

Related: What to Eat When You Have Irritable Bowel Syndrome

Research on Coffee and IBS Has Mixed Findings

Although coffee is a trigger food for some people with preexisting IBS, frequent coffee drinkers may actually have a lower risk of developing the digestive disorder over their lifetime, according to the International Journal of Epidemiology study. Notably, this study only considered people who did not have IBS and followed them to see if they developed it.

Researchers considered participants’ daily coffee and tea intake. They found those who consumed four or more cups of instant or ground coffee per day had a 19% lower risk of IBS development compared to caffeine abstainers. This association was also noted, albeit at lower rates, for people who drank 1–3 cups of coffee daily, but there was no significant trend for decaf coffee drinkers.

Those who drank small amounts of tea—half a cup to a cup per day—also had lower odds of developing IBS. However, frequent tea drinkers who had more than a cup a day had similar odds to those who abstained from caffeine altogether.

Crespin said he typically recommends no more than two cups of coffee per day to his patients, especially older adults. Consuming too much caffeine risks raising your heart rate and blood pressure to dangerous levels. Of course, there’s always decaf coffee, but studies have shown that the milder brew doesn’t have as strong of a laxative effect.

This might be good news for people with preexisting IBS-D. In a 2021 study, researchers found a “significant positive association between coffee and caffeine intake and odds of IBS in the whole population.” A closer look at the study data reveals that the association was strongest for women and people with clinical overweight, and the latter category experienced more severe IBS symptoms with increased coffee consumption.

In another study of adults with IBS, an intake questionnaire put coffee in the top ten foods to avoid if you have IBS. The data, based on patient lifestyles and healthcare provider recommendations, found coffee to be a less common dietary trigger compared to onions and garlic. Still, 26.6% of adults with IBS said they had been advised to steer clear of coffee.

Related: Different Drink Options for When You Have IBS

Why Does Coffee Make You Poop?

Both regular and decaffeinated coffee can help to stimulate bowel movements. A hot brew will help increase blood flow and activity in the gastrointestinal tract, and the caffeine in most coffee drinks also helps your intestinal muscles contract, holistic dietician Jenna Volpe, RDN, told Verywell.

“By nature, coffee acts like a digestive bitter, which stimulates the release of certain gastric juices that aid in digestion,” Volpe said.

For people who don’t make enough digestive enzymes, this extra acid is just what the doctor ordered. Stomach acid is essential for breaking down fats and proteins, absorbing nutrients, and having regular bowel movements. But too much acid can cause diarrhea, reflux or heartburn, Volpe said, which is why coffee may exacerbate those symptoms for some people with IBS.

Drinking coffee will either bring you more into balance or a little bit out of balance, so it’s important to listen to your body and consider how coffee impacts you specifically.

“We can’t really make a blanket statement that coffee is good for IBS or coffee is bad for IBS because everybody’s body is uniquely hardwired,” Volpe said.

Related: Is Coffee Bad for You?

What Causes IBS?

IBS is a chronic condition, meaning people diagnosed with the disorder must navigate its symptoms for the long haul. IBS is more common in women, but anyone can be affected. Some people with IBS can manage their symptoms with changes to their diet and lifestyle. Medication may also help people with more severe symptoms.

Symptoms of IBS include cramping, abdominal pain, bloating, gas, and diarrhea or constipation—or both. While these symptoms are not life-threatening, they can be uncomfortable and disruptive to your emotional and social well-being.

Although the exact cause of IBS is unknown, researchers have identified genetic markers linking the digestive disorder with chronic anxiety. This doesn’t mean anxiety causes IBS, or vice versa, but the processes have a shared genetic root. Additionally, various stimulants—including stress, hormonal changes, and dietary triggers—may exacerbate IBS symptoms.

The types of bacteria living in your gut may also serve as a marker for IBS, Volpe told Verywell. Volpe, who specifically uses nutrition to treat gut disorders, said her patients with IBS all have some imbalance in their gut microbiome, whether that’s an overgrowth of harmful bacteria or a deficit of helpful microbes. Studies have identified a potential influence of gut microbiota on future treatments for IBS, but more research is needed to get there.

And because a person’s gut microbiome is as unique as a fingerprint, Volpe said solutions are rarely one-size-fits-all.

Related: 10 Things to Stop Doing When You Have IBS

What This Means for You

If you’re a coffee drinker, you may have a lower risk of developing IBS than those who abstain. As IBS can be a tricky disorder to manage, people with it may feel left to their own devices when it comes to finding the optimal diet and lifestyle. It’s important to remember that clinical advice varies based on the type of IBS you have—and that not all coffee drinks are created equal.