A few weeks ago the first piece on the topic of cannabis absorption was posted at The Standard and it generated a number of questions. To help answer some of those queries, we will look deeper into the process of absorption and investigate the major metabolic steps that take place when the body is processing cannabis. The absorption process is universally complex and this post will begin to scratch the surface by exploring how cannabinoids make their way from the digestive tract to the bloodstream.
The first step to absorption is simple. Whether ingesting baked goods or consuming directly with a dosing syringe, cannabis is swallowed and eaten. The upper gastrointestinal (GI) tract may potentially absorb small amounts of cannabinoids, but this part of the body is designed to get material into the stomach quickly. It’s important to note that when consuming cannabis through food, digestion begins in the mouth with the production of amylase, an enzyme that breaks starches down to sugars.
In the context of time, variance may be contingent on whether the stomach is empty or full when the cannabis is consumed. The stomach will churn things together to form chyme, specifically in the pylorus, which is the lower section of the stomach. A mixture of digested food and enzymes, the chyme will continue to do work as it slowly moves through the digestive tract. This usually takes around an hour, but the process could be expedited if the stomach is empty. It also means that, on an empty stomach, the cannabinoids in the chyme are likely to be absorbed faster in the small intestine.
Nutrients and cannabinoids are then collected through a series of veins that line the small intestine, which funnel them into the hepatic vein; the system of veins is referred to as the hepatic portal system. In this stage, blood from the hepatic portal system is sent to the liver. In the liver, a process called first-pass metabolism occurs and some of the absorbed cannabinoids are broken down, or metabolized, into other compounds. With respect to cannabis, first-pass metabolism is often confused with the notion of “activating” cannabinoids. In reality, what occurs is THC, for example, is metabolized into a number of compounds, including the highly debated 11-OH-THC, often referred to as “11-Hydroxy.” At present, there is some evidence from animal studies (mice) in the 1970s that suggests 11-OH-THC has a stronger analgesic effect than THC alone.
Not all cannabinoids are metabolized in this first pass, which is a good thing because if the liver was capable of processing cannabinoids with 100 percent efficiency, cannabis wouldn’t prove an effective therapy. From the liver, cannabinoids and their metabolites will slowly be introduced into the bloodstream via the inferior vena cava. The body has two major vena cava that are responsible for collecting all the blood returning and emptying into the right atrium of the heart. The blood volume is significant in the vena cava, one of the largest veins in the body, but because it’s a vein the blood flow is still quite slow. The true impact of the cannabis isn’t generally felt until the blood reaches the heart and is recirculated throughout the body, allowing for activation of receptors in many systems, including the central nervous system receptor.
The breakdown of the digestion process is employed to help emphasize that edible cannabis takes much longer to produce an effect. Remember the step of producing chyme alone can take roughly an hour! It’s important to stress that when medicating with edible cannabis, always start with a very small amount and slowly increase, if necessary, to find the right dose. Remember that the effect will take much longer than inhaled cannabis to set in. For further guidance, consult a physician or contact our Care Team if you have any additional questions that need to be answered.