Research & Education

CBD – A New Tool for Irritable Bowel

Cannabis sativa L., otherwise known as hemp, has received a great deal of attention as the primary source of cannabidiol (CBD), a cannabinoid compound. However, its scientific legitimacy and therapeutic potential have been overshadowed by this plant’s close cousin, Cannabis indica (marijuana), and its psychoactive cannabinoid compound, tetrahydrocannabinol (THC). Despite sharing a botanical genus, hemp and marijuana are different plants with distinct identities.

Even at first glance, the two plants are noticeably different. Cannabis indica (marijuana) is short and densely populated with broad leaves while Cannabis sativa L (hemp) is taller with long, narrow leaves. But their most significant difference lies in the composition of their constituent cannabinoids. While the flowering tops of marijuana are most often harvested as a rich source of THC, hemp is the preferred source for CBD due to its 10:1 ratio of CBD to THC. But CBD isn’t the only feather in hemp’s cap. Hulled hemp seeds are a rich source of nutrients. Three tablespoons contain over 9 grams of protein and less than 3 grams of carbohydrates as well as 210 mg of magnesium, 360 mg of potassium, 33 µg of folate and 11 grams of polyunsaturated fatty acids, including about 2.6 g of omega-3 alpha-linolenic acid (albeit with about 8 g of omega-6 linoleic acid). Hempseeds can also contribute to daily intake of iron, zinc, phosphorus, calcium, and manganese.

Research on hemp often focuses on CBD’s interaction with the endocannabinoid system (more specifically, the CB2 receptors) to modulate pain, inflammation, addiction, mood and psychosis, mental health disorders, and most recently, cancer. Another area of research for CBD which is promising but less well-known, is its effects in the GI tract and its potential to help manage symptoms associated with various gastrointestinal disorders.

In a rat model of colitis (via chemically induced mucosal inflammation), colonic tissues show increased expression of endocannabinoid components including CB1 and CB2 receptors, indicating a possible role of the endocannabinoid system in gastrointestinal inflammation. Further, studies have shown improvement in gastrointestinal inflammation when levels of cannabinoids were increased and the CB1 and CB2 receptors were activated by agonists. CBD from hemp modulates the actions of CB2. Not only might CBD directly regulate the endocannabinoid system, but research indicates  that it can alter endogenous endocannabinoid levels by inhibiting fatty acid amide hydrolase (FAAH), the enzyme that degrades a key endogenous endocannabinoid, arachidonoylethanolamine (AEA).

Cannabinoids may affect gut motility, gastric emptying, transit time, and peristalsis. CBD from hemp has been used to relax hypermotility states in animal models and also exerts anti-emetic and anti-nausea effects as it acts upon the 5-HT1A receptors. Other studies have suggested CBD is useful for alleviating gastrointestinal inflammation and protecting the intestinal barrier by interacting with the G-protein coupled receptor 55 (GPR55) in the enterocytes. In a study investigating the effects of CBD on intestinal biopsies from human subjects with ulcerative colitis and from intestinal segments of mice with LPS-induced intestinal inflammation, CBD counteracted reactive enteric gliosis by reducing astroglial signaling neurotrophin S100B, which decreases mast cells and macrophages in the intestine. CBD treatment also reduced TNF-α expression. These outcomes were found in both animal and human cell models.

Human subjects with Crohn’s disease and ulcerative colitis have shown altered endocannabinoid activity. After infiltration of inflammatory cells, the colonic epithelium displays enhanced CB2 reactivity. Activation of these receptors protects against damage of mucosal crypts and the epithelial lining. Cannabis has been used historically for gastrointestinal inflammation, but adequate research confirming its efficacy for this purpose is still scarce. Preclinical human studies with small sample sizes are promising, though, and open the way for expanded research. Some researchers have even suggested CBD be explored as a candidate for a new class of drugs for irritable bowel diseases.

Gastrointestinal conditions such as IBD have a high prevalence and can be difficult to treat. Cannabidiol, hemp’s key therapeutic constituent, may earn a place among other botanicals used for managing the symptoms associated with these painful and often debilitating conditions.