14 DAY TRIAL // A class of substances occurring naturally inside the human body, called endocannabinoids, may be responsible for the gluttonous response people have to fatty food. These substances might help explain why the obesity epidemic is sweeping the developed world.
Whenever ingesting fatty foods such as potato chips and french fries, a natural response is triggered in the body, which releases endocannabinoids. These chemicals act on the brain similar to how the active substance in marijuana – called tetrahydrocannabinol – does.
What this research underlines is that not only carbohydrates are responsible for our cravings of fatty food, as previous studies had suggested. The study was conducted by experts with the University of California in Irvine (UCI).
The team here, led by researchers Daniele Piomelli and Nicholas DiPatrizio, discovered the surprising natural response that fat triggers in the human body. This type of investigations might help explain why there are so many people who are fat and overweight in countries with high living standards.
According to the research team, endocannabinoids are produced in the upper gut, whenever the rats in their study were given fatty foods. The same type of effect was not noticed when the lab animals were given sugars or proteins.
The process began when the fatty food touched the tongues of rats. An electrical signal was identified as moving to the brain, and then down to the intestine, through a nervous bundle called the vagus.
Once it reaches the intestines, this signal initiates the release of digestive chemicals that other studies have linked to the presence of hunger and satiety. This is what causes most people to be unable to resist eating a second french fry or chip, the team explains.
Details of the new investigation appear in this week's online issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS). “This is the first demonstration that endocannabinoid signaling in the gut plays an important role in regulating fat intake,” Piomelli explains.
The researcher holds an appointment as the UCI Louise Turner Arnold Chair in the Neurosciences, and is also a professor of pharmacology at the university. He also explains the evolutionary imperative the body may have had for consuming a lot of fat.
In nature, fatty substances are not readily available, so animals need to consume as much of it as possible when they come across it. Fat is essential for the correct functioning of cells, and this need is what may have driven the emergence of cells that produce endocannabinoids.
The investigation was supported through grants provided by the National Institute of Diabetes & Digestive & Kidney Diseases and the National Institutes of Health (NIH) National Institute on Drug Abuse (NIDA).