Dwelling inside and on every of us is an enormous inhabitants of micro organism, fungi, protozoa, and viruses. Cumulatively, the microbiome consists of as many cells because the human physique and encodes 100 instances extra genetic materials than the human genome. As much as 1,000 totally different species of micro organism reside within the intestine alone.

With this data has come the belief that the microbiome is a key participant in human well being, affecting all the things from temper to metabolism. Microbiota contained in the intestine – a hole tube extending from the esophagus by means of the intestines to the anus – play an enormous function in human illness. Disturbances to this technique, also referred to as the gastrointestinal or digestive tract, have been related to weight problems, most cancers, and neurodegenerative issues equivalent to Parkinson’s and Alzheimer’s illness.

The way it all works is a topic of ongoing scientific inquiry, one whose central discoveries have been extensively publicized in fashionable and mass media in recent times. But there’s an essential side of the hyperlink between human well being and the microbiome that has obtained nearly no consideration outdoors the customarily obscure world of scientific journals: the function of the endocannabinoid system (ECS).

Present considering means that the ECS serves as a type of bridge between micro organism and the physique itself, together with the mind, relaying alerts backwards and forwards in a symbiotic, mutually helpful relationship. At the very least that’s the way it must be – however continual imbalance or impairment of the intestine microbiome, additionally referred to as dysbiosis, can hurt bodily and psychological well being.

In probably the most primary sense, people and different animals affect the “bugs” of their intestine primarily by means of their weight-reduction plan, together with the consumption of so-called probiotic meals that promote a wholesome microbiome. These bugs in flip assist break down meals and make vitamins extra accessible to the physique. We offer them sustenance and an amenable place to reside, they usually assist us extract as a lot diet as we will from meals within the digestive tract.

This in itself is awe-inspiring. However it additionally seems to be incomplete. Groundbreaking analysis has proven that we additionally impression our intestine microbiome by means of not solely train and sure prescribed drugs but additionally the consumption of hashish, all by way of the widespread path of the ECS.

Hashish for Intestine Well being

Interactions between intestine microbiota and the endocannabinoid system had been first explored in 2010. A Belgian analysis staff confirmed that altering the intestine microbiome of overweight mice by means of prebiotics, meals that promote the expansion of helpful micro organism, altered ECS expression in fats tissue with implications for lipid metabolism and fats cell formation.1

Extra proof got here in 2015, when researchers in Canada administered a every day routine of tetrahydrocannabinol (THC) to mice sustained on a high-fat weight-reduction plan. Intestine microbiome well being in these animals improved after 3 to 4 weeks to extra intently resemble that of animals fed a wholesome, balanced weight-reduction plan.2

Few research have investigated the results of hashish use on the human intestine microbiome, however in 2017, researchers discovered key variations amongst 19 lifetime customers and 20 non-users. Hashish customers possessed micro organism populations related to greater caloric consumption however decrease BMI, although weight-reduction plan was thought to additionally play a job.

In 2018, researchers used archived anal swabs to evaluate the microbiomes of HIV-positive people. They discovered that hashish use was related to decreased abundance of two strains of micro organism linked to weight problems.

Scientists are nonetheless attempting to know the small print. However proof is accumulating that the endocannabinoid system interacts instantly and bidirectionally with micro organism within the intestine, influencing the exercise and make-up of the microbiome whereas concurrently serving to to transmit its messages to the physique and mind. What’s extra, microbiome well being could also be modified and even improved by means of plant cannabinoids, together with each THC and cannabidiol (CBD), in addition to by means of the physique’s personal endocannabinoids, anandamide and 2-AG, whose manufacturing is stimulated by means of train and the consumption of sure meals.34567.8

A Pioneering Research

Simply because the make-up of our microbiome relies on greater than weight-reduction plan, the micro organism dwelling in our intestine do greater than merely break down meals. In addition they assist regulate the epithelial barrier, a essential protecting layer lining the inside of the lengthy, slim “tube” we name the intestine or gastrointestinal tract. How do they do it? At the very least partially by means of interactions with the ECS, particularly CB1 cannabinoid receptors, in keeping with a pioneering 2012 examine whose implications are nonetheless being sorted out.9

The epithelial barrier performs a massively essential function in sustaining total well being and keeping off illness, says College of Calgary professor and researcher Keith Sharkey, who has studied the intestine for many years and, extra just lately, each the microbiome and the ECS. He additionally served as senior writer of the aforementioned 2015 examine wherein THC was administered to mice.

“The epithelial barrier could be very essential to sustaining what we name homeostasis, or the conventional physique’s features,” Sharkey says. “The management of that wonderful lining is extraordinarily rigorously managed by the physique. We’ve developed as mammals this very intricate management system, which prevents harm or rapidly repairs harm, to forestall additional erosion of our our bodies. The micro organism we’ve got in our intestine contributes to that system. And evidently the ECS is an important management factor.”

Sharkey is at present main analysis to verify whether or not CB1 receptors play a job within the acute regulation of epithelial barrier perform. Preliminary proof helps this speculation, he says.

Although he isn’t investigating concurrent modifications to the microbiome, a hyperlink would make sense provided that intestine micro organism work together extensively with the epithelial barrier. “We reside in a mutualistic symbiotic relationship,” Sharkey says.

Focusing on the Microbiome

This all factors in a predictable course. If the ECS communicates with each the intestine barrier and the microbiome, whose well being is crucial to human well-being, and we all know we will manipulate the ECS by means of weight-reduction plan, train, and cannabis-derived compounds, would possibly there be different methods to focus on the microbiome by means of the ECS so as to obtain particular well being outcomes?

It’s a query the pharmaceutical trade has been actively investigating, says Cris Silvestri, a professor at Laval College in Quebec and the Sentinel North Associate Analysis Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Well being. Although no medicine have but been developed for this function, Silvestri says the fast-growing discipline may begin producing solutions inside the subsequent 5 years that can level on to pro- or post-biotics that can be utilized to tweak the intestine microbiome by way of the ECS.

In reality, Silvestri and colleague Vincenzo DiMarzo say they’re already working with a pharmaceutical firm on associated analysis – although they will’t present any particulars. Silvestri was, nonetheless, in a position to focus on one other analysis venture below growth with the Quebec authorities, which is hoping to study extra about interactions between hashish and the intestine microbiome following Canada’s legalization of hashish edibles earlier this 12 months, Silvestri says.

“We’re in discussions for a venture with the federal government to know how edibles are going to have an effect on your intestine microbiome, and the way is that doubtlessly going to have an effect on your response to edibles,” he says. “Is the intestine microbiome going to vary these cannabinoids, make them kind of energetic?”

Silvestri can also be concerned in two extra research that can shed extra mild on this complicated relationship. One is investigating results on the intestine microbiome of genetic modulation of the ECS, which will increase 2-AG ranges and suppresses CB1 exercise in handled mice. This builds on analysis revealed in January 2020 by the identical staff displaying that experimentally managed alteration of the intestine microbiome resulted in important modifications to gene expression and signaling inside the endocannabinoidome, a broader system of receptors, enzymes, and lipid mediators associated to the ECS.10

The opposite present examine seems to be at ECS ranges within the brains of so-called germ-free mice, which haven’t any microbiome, and related impacts on habits and anxiousness. It additionally evaluates results on each after the introduction of a microbiome by means of a fecal microbiota transplant.

“The hope is that there will likely be therapeutic purposes ultimately,” Silvestri says. “The drive comes from having the ability sooner or later to reap the performance of those bugs to enhance human well being.”


A cannabinoid science lab led by Prakash Nagarkatti on the College of South Carolina can also be pioneering investigations into the ECS, the intestine microbiome, and illness. It could even have discovered a clue for treating some of the dangerous problems of COVID-19 in some sufferers.

In a June 2020 examine revealed in Frontiers in Pharmacology, Nagarkatti and colleagues demonstrated that administering THC to mice affected with a type of acute respiratory misery syndrome (ARDS) may cease the situation in its tracks.11 A extreme consequence of the runaway immune response often known as a cytokine storm, ARDS happens in a small proportion of COVID-19 sufferers however is commonly deadly.

“We’ve a mouse mannequin of ARDS, the place we inject Staphylococcal enterotoxin B [a bacterial toxin], and the mice die inside 4 or 5 days due to cytokine storm and ARDS within the lungs,” Nagarkatti says. “And we discovered that when you give THC, it cures the mice. They’re simply operating round wholesome. That was superb.”

Nagarkatti doesn’t know precisely the way it occurs, however he does comprehend it entails the microbiome. “What we discovered was that THC was altering the intestine microbiome, in addition to the microbiome within the lungs, and there have been related modifications within the intestine in addition to within the lungs, after which on prime of that, after we transplanted the fecal materials from the cannabinoid-injected mice into the conventional mice, even they turned immune to the ARDS or cytokine storm.”

Although this was demonstrated in mice and is due to this fact circuitously transferable to people – or COVID-19, for that matter – that is maybe the primary proof that cannabinoids’ alteration of the intestine microbiome can play a job in suppressing the systemic irritation seen in a cytokine storm, Nagarkatti says.

Apparently, in one in every of its first papers on the ECS and the microbiome again in 2017, Nagarkatti’s lab additionally demonstrated that remedy with a mix of THC and CBD altered the intestine microbiome in mice in a means that lowered irritation, on this case with helpful implications for autoimmune illness.12

“Suppressing irritation within the colon in addition to systemically could be very essential for stopping any sort of illness, as a result of proper now irritation is taken into account to be the underlying reason for all the things, not solely autoimmune illness however cardiovascular and neurodegenerative ailments, PTSD, Alzheimer’s, weight problems, cancers, COVID-19,” Nagarkatti says. “You title it and there’s irritation.”

Whereas the molecular mechanisms nonetheless have to be labored out, the ECS performs an essential function in modulating irritation by means of intestine microbiota.13 Nagarkatti stories: “THC alters the microbiome within the intestine in a means that appears to be helpful in suppressing irritation as a result of micro organism which might be favored by THC or cannabinoids appear to supply short-chain fatty acids that suppress irritation.”

Unanswered Questions

Nagarkatti’s lab has additionally proven that THC remedy in mice results in elevated ranges of micro organism within the helpful genus Lactobacillus, usually present in fermented meals and dietary dietary supplements.14

In any other case researchers know little about which particular “bugs” from among the many roughly 1,000 species of micro organism within the intestine are modulated by the ECS, or which species are themselves in a position to modulate the ECS, says Silvestri.

Certainly, there stays rather more to study interactions between the ECS and the microbiome. Sharkey has his personal listing of unanswered questions that would turn out to be analysis priorities as the sector progresses.

“We don’t fairly know if it’s taking place all through the intestine or if it’s restricted to sure areas of the intestine,” he says. “We don’t know the interactions between varied dietary constituents and the best way that they modify the microbial parts of the intestine in addition to the ECS. We don’t know what number of constituents of the hashish plant are in a position to regulate the intestine microbiome. We’ve but to know how the physique’s personal endocannabinoids actually regulate epithelial barrier perform.

“There are very, very many unanswered questions, however they’re thrilling as a result of the implications have the potential to be essential for well being,” he continues. “Nearly every day once I look within the literature now, a brand new factor pops up that hyperlinks the intestine to bodily well being: gut-heart connections, gut-lung connections, gut-kidney connections. So it will not shock me to see a job for the ECS in lots of these hyperlinks. And we’re simply scratching the floor of that proper now.”

Nate Seltenrich, an unbiased science journalist primarily based within the San Francisco Bay Space, covers a variety of topics together with environmental well being, neuroscience, and pharmacology.

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