Can Cannabis Help Your Gut?

When Joe Silverman developed Crohn’s disease at age 21, the symptoms started out mild. While the sight of blood in his stools initially freaked him out, what really bothered him was the frequent abdominal pain and bloating that occurred as his condition progressed to moderate and then severe. Dietary changes didn’t make a difference, so he began taking prescription oral anti-inflammatory drugs that are often used to treat certain bowel diseases, which alleviated but didn’t eliminate his discomfort. He started using prescription steroid suppositories to cope with flare-ups of the inflammatory bowel disease.

Even so, “I didn’t feel well—my mind was cloudy and I was in pain,” says Silverman, now 47, the co-founder of the PSMC5 Foundation, which is dedicated to beating rare genetic disorders like the PSMC5 gene mutation (which his son has). So in 2013, he tried a new approach: he began getting intravenous infusions of an immunosuppressive drug at four- to eight-week intervals to reduce inflammation in the lining of his intestines. “It helped, but I still had nausea, brain fog, discomfort and trouble sleeping,” says Silverman.

In 2018, he decided to try something different as an adjunctive treatment, with his gastroenterologist’s blessing: medical marijuana in the form of cannabidiol (CBD) and tetrahydrocannabinol (THC) capsules that he was able to purchase after getting a New York City medical-marijuana license. “Within an hour and a half of taking them, I felt better,” Silverman says. “The bloating and pain went down, and my appetite came back.”

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For centuries, marijuana, which is derived from the plant Cannabis sativa, has been used for both medicinal and recreational purposes. On the medicinal front, cannabinoids—a group of compounds that constitute the active ingredients in the marijuana plant—have been found to help alleviate chronic pain, as well as the nausea and vomiting that stem from chemotherapy for cancer. The U.S. Food and Drug Administration (FDA) has even approved specific cannabinoid products for chemotherapy-induced nausea and vomiting in cancer patients and to stimulate appetite in patients with AIDS who have lost weight.

In recent years, there has been growing interest in the use of medical marijuana for gastrointestinal disorders, such as inflammatory bowel diseases (IBD) like Crohn’s and ulcerative colitis (UC). In a study in the December 2013 issue of the journal Inflammatory Bowel Diseases, researchers surveyed 292 patients with IBD at a major medical center in Boston about their use of marijuana and found that 12% were active users and 39% were past users. Among current and former users who used marijuana products for their symptoms, the majority felt that it was “very helpful” in relieving their abdominal pain, nausea and diarrhea. More recently, a 2018 study in the Journal of Pediatrics found that among 99 teen and young-adult patients with IBD, nearly one-third had used marijuana—and 57% of the users endorsed its use for at least one medical reason, most commonly relief of physical pain.

“A lot of people perceive this as a more natural therapy and preferentially want this over immunosuppressants for inflammatory bowel disease,” says Dr. Byron Vaughn, an associate professor of medicine and co-director of the IBD program at the University of Minnesota in Minneapolis. But if anything, experts see the primary role for cannabis as an adjunctive therapy, not as a replacement for medications that are used to treat IBD and other GI disorders.

Help or hype?

Research investigating the effects of medical marijuana on various gastrointestinal disorders is limited, so there are many unanswered questions. Right now, one of the obstacles to this is the classification of cannabis as a Schedule I drug (along with heroin, LSD and ecstasy) by the federal government. This reality has inhibited research in the U.S. to evaluate the effects of cannabis on various gastrointestinal disorders as well as other medical conditions.

And while the mechanisms of action aren’t completely understood, this much is clear: the human body has an endogenous cannabinoid system—one that originates inside the body—that comprises cannabinoid receptors, endogenous cannabinoids (lipids that engage cannabinoid receptors), and enzymes that are involved in the synthesis and degradation of the endocannabinoids. In particular, CB1 receptors are abundant in the central nervous system, while CB2 receptors are more prevalent throughout the gastrointestinal tract, explains Dr. Jami Kinnucan, an assistant professor of medicine in the division of gastroenterology and hepatology at the University of Michigan in Ann Arbor.

A little background about cannabis: while it contains hundreds of compounds, the most well-known are THC and CBD. THC is responsible for marijuana’s psychoactive effects (that “high” sensation), whereas CBD is not psychoactive but seems to modulate the effects of THC, explains Dr. Christopher N. Andrews, a clinical professor of gastroenterology at the University of Calgary.

As far as inflammatory gastrointestinal disorders go, the greatest symptom benefit seems to come from preparations that have a combination of THC and CBD, Kinnucan says. This is partly because while CB1 receptors are activated by THC, CBD and THC have a synergistic effect on CB2 receptors. “In patients with inflammatory bowel disease, studies have shown that the combination improves abdominal pain and decreases bowel movement frequency,” she says. What’s more, cannabis use appears to decrease emptying of the stomach and gastric-acid production, as well as reduce the movement of food throughout the gastrointestinal tract, notes Dr. David Poppers, a clinical professor of medicine in the division of gastroenterology and director of GI Quality and Strategic Initiatives at NYU Langone. As a result, cannabis use may improve the diarrhea-predominant form of irritable bowel syndrome (IBS), he says.

Whether cannabis actually improves the underlying causes of GI disorders is less clear. “In the test tube, all cannabinoids have some anti-inflammatory effects,” says Dr. Jordan Tishler, an instructor of medicine at Harvard Medical School and president of the Association of Cannabinoid Specialists, a professional organization dedicated to education about cannabinoid medicine. “In human studies, if you look for blood markers of inflammation, you don’t see any change after using cannabis.” When it comes to treating IBD, “there isn’t a lot of evidence that cannabis really modifies the underlying disease process,” Tishler says. “But it treats the symptoms people have.”

Other experts agree. “When you tease it out, this is more of a symptom-based therapy,” Vaughn says. “With IBD, there seems to be a calming effect on symptoms such as nausea, vomiting, pain and diarrhea.” Vaughn reports that he sees patients with Crohn’s disease get more of an effect from cannabis than those with ulcerative colitis.

In a review of 20 studies in a 2020 issue of the Journal of Clinical Gastroenterology, researchers examined cannabis use among patients with IBD and found that cannabinoids had no effect on inflammatory biomarkers, and they were not effective at inducing remission, which is the ideal end point. However, patients who used cannabinoids reported significant improvements in abdominal pain, nausea, diarrhea, appetite and overall well-being. Similarly, a double-blind, randomized, placebo-controlled study in a 2021 issue of PLoS One found that patients with mild to moderate ulcerative colitis who smoked marijuana cigarettes daily for eight weeks—while continuing to take their usual UC medications—experienced improvements in their symptoms and quality of life, compared with those who were given placebo cigarettes, which contained cannabis flowers from which THC had been extracted. However, neither group experienced reduced inflammation, based on blood tests.

All that said, it’s possible that the impacts of cannabinoids on symptoms could have trickle-down effects that decrease the need for other prescription drugs. For example, a study in a 2019 issue of the European Journal of Gastroenterology & Hepatology found that when patients with IBD used medical cannabis to treat their symptoms, their need for other medications was significantly reduced over the course of a year because their symptoms improved.

Potential drawbacks

A cautionary note: there’s a tipping point with using cannabis for GI disorders. “Cannabinoids reduce the tone of the lower esophageal sphincter, which can increase heartburn and reflux symptoms,” Kinnucan says. “They also decrease gut motility, causing the stomach to empty more slowly, which can increase nausea and be problematic for patients with gastroparesis,” a disorder that delays the movement of food from the stomach to the small intestine.

Another potential risk: chronic, daily cannabis use can cause cannabinoid hyperemesis syndrome, which is characterized by recurrent nausea, vomiting and abdominal pain, Andrews notes. “Some people have many months with cannabinoid hyperemesis. Even if they stop using cannabis, it’s possible [their usage] may have induced a permanent change.” In addition, some develop a cannabis-use disorder, a form of dependence that occurs when the brain adapts to ongoing use of the drug. A study in a 2020 issue of the journal Drug and Alcohol Review found that approximately 27% of lifetime marijuana users develop a cannabis-use disorder, which is defined as problematic or continued use despite experiencing loss of control, social or medical problems, cravings, tolerance or withdrawal.

“We don’t know what the right dose is where patients can have the positive effects and avoid the negative effects—and not all patients respond the same way to the same dose,” Kinnucan says. Plus, cannabis is used in many different ways—as edibles, smoking or vaping, dabbing, oils or tinctures—and the dosing is different with each route.

“There’s little regulation of cannabis, and the THC levels are extremely high now,” Andrews says. Thirty years ago, the percentage of THC in typically accessible marijuana was in the single digits, he says, whereas these days THC is often 20% or higher. With these higher concentrations, “we have no idea what they will do to the [body’s] cannabinoid system long term,” Andrews says.

There’s also a concern that people with IBD and other gastrointestinal disorders might stop using other treatments that have been approved by the FDA for their condition. “Because they feel better, they may have a false sense that they are better,” Kinnucan says. “It’s important to continue medical therapy to prevent progression of the disease. We know that medication non-adherence is associated with clinical relapse of IBD and could have implications on future disease outcomes.”

Looking ahead, “what we need is to really start doing large, multicenter, randomized, controlled studies to examine the effects on IBD, using specific forms of cannabis at specific doses,” Tishler says. Until more is known, the onus is on patients to take precautions. For one thing, if you’re interested in trying it, find out what the laws are in your area: while some states have fully legalized marijuana, others allow it only for medical purposes, and still others continue to treat it as fully illegal. You’ll also want to find out what your employer’s policy is regarding medical marijuana use, in case there’s a chance that you may be drug-tested. “With chronic use, marijuana stays in your system for a long time,” Vaughn says.

If you’re already using marijuana, whether for medical or recreational reasons, it’s important to tell your doctors—regardless of whether it’s legalized where you call home.

Wherever you live, “you need to talk to your doctor about whether this is right for you,” Vaughn says. “It’s good to be open—your doctor is not going to be judgmental.” While this may seem like a privacy issue, it’s important to realize there could be medical risks. For one thing, cannabis can have potential interactions with other medications, such as warfarin (an anti-coagulant), benzodiazepines and barbiturates, Kinnucan warns. Cannabis use is also more likely to cause problems with certain groups of people, like those who are pregnant or breastfeeding, who have significant psychiatric disorders or who have a history of substance abuse, Poppers says.

Finally, remember that experts primarily view cannabis as adjunctive therapy—a potential addition on an as-needed basis—for GI disorders. “This is not a panacea or a miracle drug,” Vaughn says. “For some people, it helps their symptoms, and for some people it doesn’t.”

While Joe Silverman found that medical marijuana does help ease his Crohn’s disease symptoms, he has prioritized finding the most effective drug to treat the underlying cause of his condition. At the beginning of 2021, he and his doctor shifted the course of his treatment, and he began getting intravenous infusions of a different immunosuppressant drug every six weeks. “It has kept the inflammation [of my Crohn’s disease] at bay,” he says. Silverman continues to use medical marijuana for flare-ups or tougher days in a measured fashion. “With being able to measure these cannabinoid products by a dosed milligram each time, I still feel in control mentally and physically while reducing pain in my gut.” That’s the best of both treatment avenues.