Food for Thought
Cannabis has been a friend to humankind since before the written word, providing fiber for cordage and cloth, seeds for nutrition, and roots, leaves and flowers for ritual and healing. During the Neolithic period, our ancestors discovered uses for every part of cannabis, which was one of the first agricultural crops, perhaps the first, ever to be grown and harvested some 12,000 years ago.
Agriculture, strictly speaking, is not a natural phenomenon. It is an expression of human ingenuity, an invention that has been described as the basis – literally the ground – of modern civilization. “The onset of agriculture was probably one of the most dramatic and important developments in human history,” writes Swiss scientist Jürg Gertsch, who explores the profound consequences of dietary changes brought on by food cultivation in a recent article in the British Journal of Pharmacology, entitled “Cannabimimetic phytochemicals in the diet – an evolutionary link to food selection and metabolic stress adaptation?”
Gertsch’s provocative thesis is that chronic metabolic disorders, currently a worldwide pandemic, are rooted in “a mismatch between ancient genes and high caloric diets” that ensued with the introduction of agriculture. “The multimillion year evolutionary process during which nearly all genetic change reflected the life circumstances of our ancestors [was] suddenly disturbed” when “carbohydrate farming” supplanted the “hunter-gatherer diet rich in animal food,” says Gertsch, who maintains that “the interplay between diet and the endocannabinoid system” is key to understanding today’s obesity/diabetes crisis and its potential remediation.
The endocannabinoid system, an ancient biological signaling network, regulates numerous physiological processes, including intestinal function, glucose metabolism, and the stress response. A dysregulated endocannabinoid system is implicated in metabolic and bowel pathologies and many other diseases. Gertsch discusses the different, yet complementary, roles of the cannabinoid receptors – CB1 and CB2 – pertaining to diet, digestion, and energy metabolism.
Mammalian CB1 receptors are concentrated in the brain and the central nervous system. They are also present in taste buds and the enteric nervous system (the gut-brain axis). Tetrahydrocannabinol (THC), marijuana’s main psychoactive component, boosts appetite and food intake by binding to the CB1 receptor – a phenomenon playfully known as “the munchies.” But CB1 receptors, as Gertsch points out, “can exert paradoxical effects on food intake,” facilitating essential nourishment as well as metabolic imbalance.
CB1 receptor signaling triggers a newborn’s suckling instinct. Mother’s milk is well endowed with arachidonic acid, a basic building block of the brain’s own marijuana-like compounds, anandamide and 2AG. These endogenous cannabinoid compounds bind to the same cell receptors – CB1 and CB2 – that mediate many of the effects of marijuana. Found in eggs, meat, and dairy products, arachidonic acid intake increases endocannabinoid levels in different tissues and is crucial for pre- and post-natal brain development.
Early hominids lived a precarious wilderness existence, requiring significant physical exertion (hunting and gathering) for survival. Famine, microbial infection, traumatic encounters with predators, fight or flight – all were hallmarks of a pre-agriculturist, subsistence lifestyle. Given the metabolic demands of their large brains and strenuous daily activities, our ancestors needed to consume energy-dense, nutrient-rich food.
In addition to heightening one’s sense of smell and stimulating appetite, CB1 receptor signaling “may facilitate survival after excessive physical activity, stress and trauma by restoring homeostasis, suppressing negative memories and reducing anxiety at the level of the central nervous system,” writes Gertsch, who explains that “CB1 receptor activation is associated with increased energy intake and decreased energy expenditure by controlling neural pathways.”
And CB1 taketh away
Combined with rigorous, day-to-day aerobics, the hunter-gatherer diet did not engender obesity, metabolic problems or cardiovascular disease. But the high-fat hunter-gatherer diet, which served our ancestors well, changed significantly with the advent of cultivated food. “Carbohydrate farming incited the most important dietary transition, which is still ongoing to the present day,” says Gertsch. There is a continuum, he maintains, between plant carbohydrate cultivation of yore and today’s over-starched, over-sweetened and over-processed Western diet.
Grain, carbs, sugar, alcohol, high fructose corn syrup: What started as the basis of civilization has spiraled into a mass-marketed refined sugar binge. “Dietary carbohydrates once essential for the cognitive and social development of Paleolithic humans gradually turned into a metabolic stress factor as a function of their glycemic indices,” Gertsch explains. “Epidemiological evidence points toward a pandemic diet-induced glucose toxicity due to excess sugar intake.”