From https://www.sciencealert.com/new-discovery-coffee-affects-steroid-endocannabinoid-metabolites
The study: https://onlinelibrary.wiley.com/doi/abs/10.1111/joim.12737. Sorry, full study is paywalled.In between the hype and the headlines, the truth is always more complicated. And this latest study shows us just why – it turns out the compounds in our daily cup of joe change more metabolites in our blood than previously known.
The investigation entailed 47 coffee drinkers to give up the habit for a month before throwing back four cups of coffee each day for the next 30 days. Following that, they upped their coffee intake to eight cups. All the while, researchers were taking blood samples to analyse changes in biochemistry that result from consuming food and drink.
The resulting profile revealed 115 metabolites were impacted by the consumption of coffee. A total of 82 of those chemicals were already known, and could be mapped to 33 metabolic pathways, a number of which were completely new relationships. For example, drinking around eight cups of coffee a day has a knock-on effect causing a drop in the kinds of neurotransmitters mimicked by cannabis.
In other words, where cannabis ramps up our body's endocannabinoid system, something in coffee seems to drive down the system's neurotransmitters, putting it into low gear. Our body tends to decrease its production of endocannabinoids in times of stress, making the researchers question the relationship between coffee and how our body adapts to change.