The relationship between cannabis use and acid reflux, or gastroesophageal reflux disease (GERD), is complex. GERD is a chronic condition where stomach contents flow backward into the esophagus, causing irritation and heartburn. Cannabis compounds interact with the digestive system in ways that can produce contradictory effects, meaning the outcome is determined by physiological mechanisms, the specific compounds consumed, and the method of consumption.
Cannabis Interaction with the Gut-Brain Axis
The digestive tract is linked to the nervous system through the gut-brain axis, a communication network regulating gastrointestinal function. Cannabis components interact with the body’s native signaling system, known as the Endocannabinoid System (ECS). The ECS includes cannabinoid receptors, primarily CB1 and CB2, which are distributed throughout the central nervous system and the enteric nervous system.
CB1 receptors are prevalent in the gut, where their activation influences motility, secretion, and sensation. By modulating nerve signaling in this axis, cannabinoids can regulate processes like the perception of pain, nausea, and the movement of food through the stomach and intestines. This system explains why cannabis can affect various gastrointestinal symptoms, including those associated with reflux.
Impact on Esophageal Sphincter and Gastric Emptying
Acid reflux is primarily caused by the inappropriate relaxation of the Lower Esophageal Sphincter (LES), the muscle separating the esophagus from the stomach. When the LES weakens, it allows stomach acid to wash back into the esophagus. The primary psychoactive compound in cannabis, delta-9-tetrahydrocannabinol (\(\Delta^{9}\)-THC), affects this muscle.
Research indicates that \(\Delta^{9}\)-THC can reduce the basal pressure of the LES, weakening the barrier that prevents reflux. This effect is mediated by the activation of CB1 receptors in the digestive tract. By lowering LES pressure, cannabis use may increase the incidence of acid backflow, potentially worsening GERD. Furthermore, CB1 receptor activation can delay gastric emptying, meaning the stomach holds food and acid longer. This prolonged presence increases the risk of reflux episodes and acid exposure.
Clinical Findings: Symptom Management vs. Physiological Effects
Despite the physiological risk of weakening the LES, many individuals report a reduction in acid reflux symptoms. This contradiction arises because cannabis compounds offer pain relief and anti-nausea effects. Cannabinoids modulate visceral sensation, reducing the perception of the burning pain associated with heartburn. A user may feel better because the pain signal is masked, not because the acid backflow has stopped.
Cannabis may also provide relief by reducing inflammation and alleviating stress or anxiety, both of which can exacerbate GERD symptoms. However, confusing symptom relief with a physiological cure is a concern. By reducing the painful sensation, cannabis may allow acid to continue damaging the esophageal lining without the user realizing the reflux severity. Clinical trials supporting cannabis as a long-term GERD treatment remain limited, highlighting the distinction between temporary relief and addressing the root cause.
Adverse Gastrointestinal Effects of Cannabis Use
Beyond the direct effect on the LES, cannabis use can introduce several other adverse gastrointestinal complications relevant to reflux sufferers. One condition is Cannabinoid Hyperemesis Syndrome (CHS), which affects chronic cannabis users. CHS is characterized by recurrent episodes of nausea, abdominal pain, and vomiting, which can complicate existing GERD. The cyclical vomiting associated with CHS can lead to dehydration and irritation to the esophageal lining from repeated exposure to stomach acid.
Another common side effect is dry mouth, or xerostomia, which is detrimental for those with reflux. Saliva is a natural buffer that helps neutralize and wash away acid that has entered the esophagus. Reduced saliva production removes this protective mechanism, prolonging the acid’s damage. Furthermore, the increased appetite associated with cannabis use, known as “the munchies,” can lead to overeating or consuming trigger foods like high-fat, spicy, or acidic items. Eating large quantities or consuming food close to bedtime significantly increases the risk of reflux episodes, compounding the issue for those susceptible to GERD.