Scientists have discovered a new group of molecules produced in the body that have anti-inflammatory properties similar to those of marijuana. These molecules come from cannabinoids that are made naturally from omega-3 fatty acids, which are essential nutrients found in meat, fish, eggs, and nuts.

The researchers, from the University of Illinois at Urbana-Champaign, report their findings in the journal PNAS.

Although the medicinal uses of cannabis, or marijuana, have been documented in records that go back 4,700 years, it was not until 1964 that we found out how it worked.

It was then that Israeli scientists Yechiel Gaoni and Raphael Mechoulam discovered the cannabinoid tetrahydrocannabinol (THC), the most active component in marijuana.

Since then, it has been shown that THC mimics a natural brain chemical, one of many "endocannabinoids" - that is, cannabinoids that are produced naturally in the body.

The body makes cannabinoids from foods that contain omega-3 and omega-6 fatty acids, such as eggs, meat, fish, and nuts.