Scientists at Imperial College London have found that intermittent fasting can speed up the recovery of damaged nerves. The results of the study are published in the journal Nature.

In an experiment using mice, the researchers showed that fasting gut bacteria increase the production of a metabolite known as 3-indolepropionic acid (IPA). This substance is necessary for the regeneration of nerve fibers called axons, thread-like structures at the ends of nerve cells that send electrochemical signals to other cells in the body.

The study evaluated neural tissue regeneration in mice that had undergone surgical damage to the sciatic nerve that runs from the spine down the leg. Half of the animals were subjected to intermittent fasting (eating as much as they wanted and then not eating at all every other day), while the other half could eat without any restrictions. These diets were continued for 10 days or 30 days before surgery, and mice were observed to recover within 24-72 hours after nerve rupture.

It turned out that the length of the regrown axons was about 50 percent longer in mice that were starving. These animals were also found to have elevated levels of specific substances, including IPA. To confirm whether IPA leads to nerve recovery, the mice were treated with antibiotics to clear their intestines of any bacteria. After that, they were introduced with genetically modified strains of Clostridium, which may or may not produce IPA.

In the event that bacteria do not produce 3-indolepropionic acid and it is almost absent in the serum, regeneration is impaired. This proves that IPA, which is produced by these bacteria, is able to activate the regeneration of damaged nerves.