To better understand how cannabis impacts the gut, it’s helpful to know a little about how the herb engages the body. The active compounds in cannabis interact with cells in the body through the endocannabinoid system (ECS).
The ECS is a large communication network in the body. It is made up of cell receptors, chemical compounds, and the enzymes that make the chemical compounds.
The cell receptors are called cannabinoid receptors, and thus far, there are two of them: CB1 and CB2. The chemical compounds are called endocannabinoids. Endocannabinoids are the body’s natural THC. In fact, they were named after the active components of cannabis, called phytocannabinoids.
The ECS has many functions in the body. In fact, it’s primary responsibility is to promote homeostasis, which means optimum balance. This includes regulation of mood, mobility, pain, immune function, metabolism, sleep, and reproduction.
The ECS and the gut
In a way, the ECS is sort of like an orchestra conductor. It makes up the signal messages that trigger all sorts of biochemical interactions. Many of these interactions occur between the brain, the immune system, and the gut.
The gastrointestinal (GI) tract houses 80% of the immune system. GI tract also contains cannabinoid receptors. Research has shown that high levels of endocannabinoids are found throughout the digestive system.
Research is still lacking on the exact function of endocannabinoids in the gut. Yet, the ECS seems to play many roles in the GI tract. These include,
- Regulation of stomach acid
- Motility (ability to move food from the mouth and out again as a bowel movement)
- Visceral sensation (ability to perceive bodily organs)
- Inflammation (immune response)
- Satiety (feeling full)
Both the CB1 receptor and the CB2 receptor can be found in the gut. The CB1 receptor is the cell site responsible for the high caused by psychoactive THC. Though most abundant in the central nervous system, the CB1 receptor is expressed on nerves that connect the gut to the brain.
The CB2 receptor is a bit tricky. In a healthy gut, a 2008 review suggests that CB2 receptors are not very abundant. But, when the GI tract is inflamed and in the case of bowel diseases, levels of the CB2 receptor increase. The CB2 receptor is most common on immune cells.
The fact that CB2 receptors are increased in damaged or sickly intestines is a good sign that cannabinoid therapy may be useful in gastrointestinal disease. GI diseases are discussed in more detail below.
Another fascinating way the ECS engages the gut is through the gut-brain axis. In the Victorian era, it wasn’t uncommon to hear the phrase “I have bowels for you” as an expression of empathy. Today, idioms like “gut feelings” and “butterflies in the stomach” are still popular. There’s a reason this language exists. The gut and the brain are intimately connected.
One way that they are connected is through the ECS. A 2016 review published in Gastroenterology found that the CB1 receptors control the body’s visceral sensation. “Visceral sensation” is the response and perception of the internal organs. Of course, this includes the gut.
Turns out, the gut and the brain communicate with each other through what is called the “gut-brain axis”. This is a series of nerve connections and chemical signals that help the two major organ systems coordinate and send messages to each other. They are so intimately connected that recently the gut has been called “the second brain”.
When one part of the body is under stress, whether from signals from the central nervous system or signals from the gut, the other responds with vigor. The ability to feel this response partly depends on the ECS. The ECS links stress to visceral pain and GI function.
Those who’ve experienced nervous stomach or have suddenly needed to run to the bathroom after a stressful event have likely experienced the connection between the ESC, gut, and brain first hand.
How does cannabis affect the gut?
The ECS is what allows cannabis to have an effect on the body. THC activates both endocannabinoid receptors. This may explain why many with nausea and GI distress find strong relief with cannabis.
Yet, the effects of the herb largely depend on what you’ve got going on in the first place. In some people, the impacts of cannabis may be highly desirable. Cancer, IBS, and wasting disease are great examples. In others, too much cannabis may have negative impacts. Here’s why:
THC may reduce stomach acid
Have acid reflux? What about heartburn? It’s important to pay attention to whether or not cannabis makes this condition better or worse. Popular belief has it that acid reflux and heartburn are caused by high levels of stomach acid. If this is the case, then there is evidence that cannabis may help.
However, some experts suggest that low stomach acid and too much abdominal pressure may actually be the underlying issue. With low stomach acid, it’s possible that cannabis may aggravate the issue.
Here’s how cannabis is involved: the CB1 receptor tells the stomach to stop producing stomach acid. In some cases, this may be beneficial. However, if digestive problems are caused by low stomach acid, THC may not actually help.
An early study published in the 1970s found that consuming cannabis more than twice a week was associated with low stomach acid. This is potentially good news for those with peptic ulcers, yet the news isn’t so great for those who have the opposite problem.
Low stomach acid (Hypochlorhydria) means that food may not be digested properly. Some signs of low stomach acid include:
- Bloating and gas after meals
- Carbohydrate malabsorption
There is not enough research to discuss the potential impacts of cannabis on stomach acid. It is also unclear whether tolerance to THC has an impact on gastric acids. To better understand these effects, this study sorely needs to be replicated.
Some people have increased nausea with cannabis
It’s well-known that cannabis can ease stomach pain and reduce nausea and vomiting. Many even feel that they have no appetite or are unable to digest or process food without the help of cannabis. Cancer and HIV/AIDS patients with medical recommendations often experience this firsthand.
However, in some cases, chronic cannabis consumption may increase nausea and vomiting. Lately, there has been talk of a rare condition known as “cannabinoid hyperemesis syndrome”. There is very little research on the topic minus case reports.