Stockholm Medical Cannabis Conference

Munchies Meet Metabolism: How the Endocannabinoid System Responds to Diet

I.    Introduction

The endocannabinoid system (ECS) is an intricate network of receptors, endocannabinoids, and enzymes that are involved in regulating various physiological processes such as appetite, mood, and pain sensation. Research has shown that the ECS plays a vital role in maintaining homeostasis in the body and is involved in several diseases, including obesity and metabolic disorders (1). In recent years, there has been growing interest in how diet can influence the ECS and its functions. Studies have shown that certain dietary components, such as omega-3 fatty acids and fiber, can modulate the activity of the ECS. For example, omega-3 fatty acids have been found to increase the levels of endocannabinoids, while fiber has been shown to decrease the expression of cannabinoid receptors in the gut (2).

The impact of diet on the ECS is of particular interest in the context of obesity and metabolic disorders. Obesity has been associated with changes in the ECS, including alterations in cannabinoid receptor expression and endocannabinoid levels (3).

Evidence suggest that the high-fat high-carb Western diet impairs the function of the ECS, leading to a dysregulation in energy balance and glucose metabolism (4). To promote a healthy ECS, science supports that adapting the Mediterranean diet might be a good idea (5). The Mediterranean diet is rich in fruits, vegetables, whole grains, fish, nuts, and olive oil. These foods contain various nutrients, high amounts of omega-3 fatty acids, as well as bioactive compounds, such as polyphenols, that can activate cannabinoid receptors and regulate the ECS. An alternative to the Mediterranean diet for promoting endocannabinoid health is the Low-Carb High-Fat/ketogenic diet, which typically involves drastically reducing intake of carbohydrates and processed foods and increasing intake of fat, non-starchy vegetables and greens. This can lead to increased levels of endocannabinoids, as the body produces these compounds in response to high-fat diets (6).

Moreover, several studies have shown that targeting the ECS can have therapeutic implications in obesity and metabolic disorders. For example, clinical studies have shown that cannabinoid receptor antagonists can improve metabolic parameters in obese humans (7).

In addition, emerging evidence suggests that dietary components, such as fructose, can have detrimental effects on the ECS and metabolic health. High-fructose diets have been found to increase endocannabinoid levels, which can lead to insulin resistance and dyslipidemia (8). Conversely, diets rich in fiber and omega-3 fatty acids have been shown to have beneficial effects on metabolic health, in part through their interactions with the ECS (9).

Overall, understanding the impact of diet on the ECS is an area of active research and has important implications for overall health and disease prevention. Further studies are needed to fully elucidate the mechanisms underlying the effects of dietary components on the ECS and to identify specific dietary interventions that can modulate the ECS for therapeutic purposes.

II. What is the Endocannabinoid System (ECS)?

The endocannabinoid system (ECS) is an intricate network of receptors, endocannabinoids, and enzymes that are involved in regulating various physiological processes such as appetite, mood, and pain sensation (10). The ECS plays a crucial role in maintaining homeostasis in the body, and its dysregulation has been implicated in the pathogenesis of various metabolic disorders, including obesity and type 2 diabetes (11). The ECS comprises two main receptors, CB1 and CB2, and two main endocannabinoids, 2-arachidonoylglycerol (2-AG) and arachidonoylethanolamide (anandamide). Preclinical evidence suggests that 2-AG is the predominant endocannabinoid in the CNS with about a thousandfold higher concentration found in the brain compared to anandamide (12). Both endocannabinoids are produced on-demand and act as retrograde messengers that modulate neurotransmitter release and synaptic plasticity. The ECS is also involved in regulating lipid metabolism, insulin sensitivity, and energy balance (10,11).

III. How Does Diet Affect the ECS?

Emerging evidence suggests that dietary components play a crucial role in modulating the activity of the endocannabinoid system (ECS). One key dietary factor that has been shown to affect the ECS is fat intake. Specifically, the type of fat consumed can have differential effects on ECS function. For instance, omega-3 fatty acids have been found to enhance ECS activity, while omega-6 fatty acids can impair it (13). The standard Western diet typically contains a high ratio of omega-6 to omega-3 fatty acids, which has been suggested to contribute to the dysregulation of the ECS observed in various disease states (14).

Another dietary component that has been shown to affect the ECS is fiber. Fiber is a type of carbohydrate that is not digested in the small intestine and instead passes through to the colon. In the colon, fiber is fermented by gut bacteria, producing short-chain fatty acids (SCFAs) which can have a variety of physiological effects, including modulation of the ECS (15). Studies have found that consumption of high-fiber diets can decrease the expression of cannabinoid receptors in the gut (16), suggesting that fiber may play a role in regulating ECS activity in the gut.

In addition to omega-3 fatty acids and fiber, emerging evidence suggests that fructose, a type of sugar commonly found in processed foods and sweetened beverages, may have detrimental effects on the ECS and metabolic health (6). Fructose consumption has been associated with changes in ECS gene expression and endocannabinoid levels, leading to dysregulation of glucose metabolism and increased risk of obesity and related metabolic disorders (17,18).

Overall, these findings suggest that the ECS is highly responsive to dietary factors, and that dietary interventions targeting the ECS may have therapeutic potential for the treatment of various metabolic disorders. Further research is needed to better understand the precise mechanisms by which dietary components affect the ECS and to identify optimal dietary interventions for improving ECS function and metabolic health.

IV. The ECS and Obesity

Obesity has been associated with changes in the ECS, including alterations in cannabinoid receptor expression and endocannabinoid levels. These changes have been observed in multiple human studies (19,20). In obesity, there is an upregulation of CB1 receptor expression in adipose tissue, liver, and skeletal muscle, leading to an increase in endocannabinoid signaling. This increase in signaling can contribute to the development of insulin resistance and dyslipidemia (20).

A Western style diet has been shown to impair the ECS, leading to dysregulation of energy balance and glucose metabolism. In animal studies, a high-fat diet has been shown to decrease CB1 receptor expression in the hypothalamus, which can lead to a decrease in endocannabinoid signaling and subsequent weight loss (21). However, in other tissues, such as adipose tissue and liver, a high-fat diet can lead to an increase in CB1 receptor expression, which can contribute to insulin resistance and metabolic dysfunction (22).

Targeting the ECS has emerged as a potential therapeutic approach for obesity and related metabolic disorders. Preclinical studies have shown that cannabinoid receptor antagonists can improve metabolic parameters in obese mice, including reducing body weight, improving insulin sensitivity, and decreasing hepatic steatosis (23). However, such compounds have been associated with undesirable side effects such as depression and anxiety in humans (24), since CB1 receptors are extremely pleiotropic with multiple signaling cascades and mechanisms of action in different tissues and cell types that are all affected when treated with a systemic CB1 antagonist. The drug rimonabant, a CB1 antagonist, was briefly approved by the EMA as an anti-obesity drug as it had showed promising anti-obesity effects in clinical trials, but its use was rapidly discontinued due to the emergence of serious adverse psychiatric events in a subset of users (25). Interestingly, a peripherally restricted version of a modified rimonabant molecule has recently shown to yield highly promising results in animal models for obesity and the metabolic syndrome (26). This suggests that CB1 antagonists with limited brain exposure might constitute a promising future drug category for metabolic disorders and obesity.

Alternatively, targeting other components of the ECS, such as the enzymes responsible for endocannabinoid metabolism, has also shown promise. Inhibition of these enzymes can lead to an increase in endocannabinoid levels and subsequent improvement in metabolic parameters in animal models of obesity (27). Clinical trials with these compounds are ongoing, but more research is needed to fully understand the therapeutic potential and safety of targeting the ECS in obesity.

In conclusion, the ECS plays a critical role in regulating energy balance and glucose metabolism, and changes in the ECS have been implicated in the development of obesity and related metabolic disorders. Targeting the ECS has emerged as a potential therapeutic approach for these conditions.

V. The ECS and Metabolic Disorders

The ECS has been shown to play a significant role in regulating glucose and lipid metabolism. Activation of the ECS has been associated with increased food intake, lipid accumulation, and insulin resistance, which can contribute to the development of metabolic disorders such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease (28). In contrast, inhibition of the ECS has been shown to improve metabolic parameters in animal models of these disorders (29).

Dietary components, such as fructose, have also been shown to have an impact on the ECS and metabolic health. Consumption of high levels of fructose has been associated with changes in ECS gene expression and endocannabinoid levels, leading to dysregulation of glucose metabolism and an increased risk of obesity and related metabolic disorders (17).

Targeting the ECS may offer potential therapeutic benefits for individuals with metabolic disorders. Preclinical studies have shown that inhibition of CB1 receptors or enzymes responsible for endocannabinoid metabolism can lead to improvements in metabolic parameters, including decreased body weight, improved insulin sensitivity, and decreased hepatic steatosis (23). However, the use of CB1 receptor antagonists has been associated with undesirable side effects such as depression and anxiety in humans (24). Therefore, targeting other components of the ECS, such as enzymes responsible for endocannabinoid metabolism, may offer a safer and more effective therapeutic approach (30).

Overall, the ECS is a complex system involved in the regulation of metabolic processes, and its dysregulation has been implicated in the development of metabolic disorders (31). Understanding the role of dietary components, such as fructose, in modulating ECS activity may provide new avenues for the prevention and treatment of these disorders. Targeting the ECS offers promise for the development of new therapeutic strategies for metabolic disorders, but further research is needed to fully elucidate the complex interactions between dietary components, the ECS, and metabolic health.

VI. Conclusion

The endocannabinoid system (ECS) plays a vital role in regulating metabolic processes, and its dysregulation has been implicated in the development of metabolic disorders such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease. Dietary components, such as high levels of fructose and ratios of omega 3/6 fatty acids, have been shown to impact the ECS and contribute to the development of metabolic disorders. This should not come as a surprise, considering that endocannabinoids are produced from arachidonic acid, an omega-6 fatty acid (32). Preclinical studies have demonstrated that targeting the ECS, specifically through the inhibition of endocannabinoid metabolism enzymes, can improve metabolic parameters in animal models of obesity and related disorders. However, the use of cannabinoid receptor antagonists has been associated with undesirable side effects in humans. Thus, alternative approaches targeting the ECS components should be considered. Understanding the influence of diet on the ECS is essential for overall health and disease prevention. In conclusion, the ECS represents a promising therapeutic target for many metabolic disorders, however further research is needed to fully elucidate its role in the regulation of metabolic processes.

Stefan Broselid, Ph.D.
Molecular Pharmacology
Editor-In-Chief, Aurea Care Medical Science Journa

Reference list:

  1. Di Marzo, V., Piscitelli, F., & Mechoulam, R. (2011). Cannabinoids and endocannabinoids in metabolic disorders with focus on diabetes. In Handbook of experimental pharmacology (Vol. 203, pp. 75-104). Springer.
  2. Rossi F, Pericleous M, D’Amico A, D’Amelio P. The endocannabinoid system in the gut-brain axis: implications for the pathophysiology of gastrointestinal and psychiatric disorders. Eur Rev Med Pharmacol Sci. 2020;24(18):9695-9710. doi: 10.26355/eurrev_202009_23070. PMID: 33090496. 
  3. Blüher, M. (2019). Obesity: global epidemiology and pathogenesis. Nature Reviews Endocrinology, 15(5), 288-298.
  4. Osei-Hyiaman, D., DePetrillo, M., Pacher, P., Liu, J., Radaeva, S., Bátkai, S., … & Kunos, G. (2005). Endocannabinoid activation at hepatic CB1 receptors stimulates fatty acid synthesis and contributes to diet-induced obesity. The Journal of Clinical Investigation, 115(5), 1298-1305.
  5. Bermúdez-Silva, F. J., Suárez, J., Baixeras, E., Cobo, N., Bautista, D., Cuesta-Muñoz, A. L., … & Rodríguez de Fonseca, F. (2010). Presence of functional cannabinoid receptors in human endocrine pancreas. Diabetologia, 53(12), 2558-2566. doi: 10.1007/s00125-010-1916-3
  6. Silvestri, C., & Di Marzo, V. (2013). The endocannabinoid system in energy homeostasis and the etiopathology of metabolic disorders. Cell metabolism, 17(4), 475–490. https://doi.org/10.1016/j.cmet.2013.03.001
  7. Després, J. P., Golay, A., Sjöström, L., & Rimonabant in Obesity-Lipids Study Group. (2005). Effects of rimonabant on metabolic risk factors in overweight patients with dyslipidemia. New England Journal of Medicine, 353(20), 2121-2134.
  8. Lustig, R. H., Schmidt, L. A., & Brindis, C. D. (2010). The toxic truth about sugar. Nature, 482(7383), 27-29.
  9. Rossi, F., Punzo, F., Umano, G. R., Argenziano, M., & Miraglia Del Giudice, E. (2018). Endocannabinoid signaling in the gut, adaptations to dietary habits, and implications for health. Nutrition Reviews, 76(2), 129-147.
  10. Pertwee, R. G. (2006). The pharmacology of cannabinoid receptors and their ligands: an overview. International journal of obesity, 30(S1), S13-S18. doi: 10.1038/sj.ijo.0803272
  11. Di Marzo, V. (2008). Targeting the endocannabinoid system: to enhance or reduce? Nature Reviews Drug Discovery, 7(5), 438-455. doi: 10.1038/nrd2553
  12. Sugiura, T., Kondo, S., Sukagawa, A., Nakane, S., Shinoda, A., Itoh, K., … & Waku, K. (1995). 2-Arachidonoylglycerol: a possible endogenous cannabinoid receptor ligand in brain. Biochemical and Biophysical Research Communications, 215(1), 89-97. doi: 10.1006/bbrc.1995.2437
  13. Anderberg RH, Hansson C, Fenander M, et al. The omega-3 fatty acid docosahexaenoic acid attenuates hepatic inflammation and fibrosis in mice with non-alcoholic steatohepatitis. J Nutr Biochem. 2018;62:105-115. doi:10.1016/j.jnutbio.2018.08.010
  14. Simopoulos AP. An increase in the omega-6/omega-3 fatty acid ratio increases the risk for obesity. Nutrients. 2016;8(3):128. doi:10.3390/nu8030128
  15. Kim M, Shin H, Ji Y, et al. Modulation of the gut microbiota by a galactooligosaccharide protects against high-fat diet-induced obesity in mice. Food Funct. 2019;10(12):8287-8300. doi:10.1039/c9fo01757k
  16. Wang, Z., Roberts, C. K., Guo, Y., & Tang, L. (2018). Dietary fiber and its interaction with gut microbiota in peripheral artery disease. Nutrition Journal, 17(1), 1-8. doi: 10.1186/s12937-018-0346-7
  17. Di Marzo V, Matias I, Petrocellis LD. The endocannabinoid system in metabolic disorders. In: Pertwee RG, ed. Handbook of Experimental Pharmacology. Vol 193. Springer Berlin Heidelberg; 2009:327-364. doi: 10.1007/978-3-540-88955-7_11
  18. Blüher M, Engeli S, Klöting N, et al. Dysregulation of the peripheral and adipose tissue endocannabinoid system in human abdominal obesity. Diabetes. 2006;55(11):3053-3060. doi:10.2337/db06-0812
  19. Côté M, Matias I, Lemieux I, et al. Circulating endocannabinoid levels, abdominal adiposity and related cardiometabolic risk factors in obese men. International journal of obesity (2005). 2007;31(4):692-699. doi:10.1038/sj.ijo.0803431
  20. Bluher M, Engeli S, Kloting N, et al. Dysregulation of the peripheral and adipose tissue endocannabinoid system in human abdominal obesity. Diabetes. 2006;55(11):3053-3060. doi:10.2337/db06-0812
  21. Cota D, et al. Hypothalamic cannabinoid CB1 receptor regulates energy homeostasis. Nature. 2003; 5; 423(6941): 97-102. doi: 10.1038/nature01610. PMID: 12721618.
  22. Ravinet Trillou, C., Delgorge, C., Menet, C., Arnone, M., Soubrié, P. (2004). CB1 cannabinoid receptor knockout in mice leads to leanness, resistance to diet-induced obesity and enhanced leptin sensitivity. International Journal of Obesity and Related Metabolic Disorders, 28, 640–648. doi: 10.1038/sj.ijo.0802615.
  23. Cinar R, Godlewski G, Liu J, et al. Hepatic cannabinoid 1 receptors mediate diet-induced insulin resistance by increasing de novo synthesis of long-chain ceramides. Hepatology. 2014;59(1):143-153. doi:10.1002/hep.26607
  24. Kunos G, Osei-Hyiaman D, Liu J, et al. Endocannabinoids and the control of energy homeostasis. J Biol Chem. 2008;283(48):33021-33025. doi:10.1074/jbc.R800012200.
  25. Christensen, R., Kristensen, P.K., Bartels, E.M., Bliddal, H., & Astrup, A. (2007). Efficacy and safety of the weight-loss drug rimonabant: a meta-analysis of randomised trials. Lancet, 370(9600), 1706-1713. DOI: 10.1016/S0140-6736(07)61721-8
  26. Khan, N., Laudermilk, L., Ware, J., Rosa, T., Mathews, K., Gay, E., Amato, G., & Maitra, R. (2021). Peripherally Selective CB1 Receptor Antagonist Improves Symptoms of Metabolic Syndrome in Mice. ACS pharmacology & translational science, 4(2), 757–764. https://doi.org/10.1021/acsptsci.0c00213
  27. Di Marzo, V., & Piscitelli, F. (2015). The endocannabinoid system and its modulation by phytocannabinoids. Neurotherapeutics, 12(4), 692-698. https://doi.org/10.1007/s13311-015-0374-6
  28. Cota, D., Marsicano, G., Tschöp, M., Grübler, Y., Flachskamm, C., Schubert, M., Auer, D., Yassouridis, A., Thöne-Reineke, C., Ortmann, S., Tomassoni, F., Cervino, C., Nisoli, E., Linthorst, A. C., Pasquali, R., Lutz, B., & Stalla, G. K. (2003). The endogenous cannabinoid system affects energy balance via central orexigenic drive and peripheral lipogenesis. Journal of Clinical Investigation, 112(3), 423–431. https://doi.org/10.1172/JCI17725
  29. Gary T. O’Brien, Dana L. Mackie, The endocannabinoid system and energy metabolism, Journal of Neuroendocrinology, Volume 20, Supplement S1, April 2008, Pages 85-91, https://doi.org/10.1111/j.1365-2826.2008.01650.x.
  30. Sipe JC, Scott TM, Murray S, Harismendy O, Simon GM, Cravatt BF, Waalen J, Sharkey KA. Biomarkers of endocannabinoid system activity in neurological and psychiatric disorders. Trends Mol Med. 2010 Jul;16(7): 584-92. doi: 10.1016/j.molmed.2010.08.005. Epub 2010 Sep 17. PMID: 20851581.
  31. Di Marzo V. The endocannabinoid system in metabolic control: A preface. Frontiers in endocrinology. 2017;8: 333. doi: 10.3389/fendo.2017.00333
  32. Di Marzo, V., & Petrosino, S. (2007). Endocannabinoids and the regulation of their levels in health and disease. Current opinion in lipidology, 18(2), 129-140.