Claim: Gut is our second brain

Fact: True. The gut contains a complex nervous system and produces mood-related chemicals like serotonin, significantly influencing brain function, though it doesn’t “think” like the brain.

The phrase “the gut is our second brain” has become increasingly popular in both scientific circles and social media. First Check received a question on the tipline asking if this is indeed true, and why the saying is so popular. 

Here’s what the expert says:

“It indeed is correct that our gut acts as our second brain, we are what we eat as the old saying goes, and one should take care of one’s diet,” says Dr Anil K Arora, a gastroenterologist and Hepatologist at Sir Ganga Ram Hospital, told First Check. “The phrase shows the important role the gut plays in one’s body.”

One reason for this, according to him, is the complex nervous system present in the lining of the gastrointestinal tract. 

“Known as enteric nervous system, it is responsible for controlling digestion, regulating muscle contractions, secretion of digestive enzymes, blood flow, and even interacting with the immune system within the gut,” he said adding that the enteric nervous system works in tandem with the central nervous system.

“About 90% of the signals in the vagus nerve travel from the gut to the brain, not the other way around,” Dr Arora said. “This means that the gut can significantly influence brain function and mood. Chemicals which regulate a persons moods, such as serotonin, and other neurotransmitters are also produced in the gut.”

Another important aspect of the gut is the existence of the gut microbiome. These microorganisms that inhabit our intestines can produce or stimulate the production of neuroactive substances, influencing both gut and brain function. Research has shown that changes in the gut microbiota can impact mood, behavior, and even conditions like depression and anxiety.

“The gut does communicate to the brain, but this does not mean it can think or process information as the brain,” Dr Arora said. “The gut is specialized for managing digestion, not for higher cognitive functions.” 

Also read: Fact Check: Do Fruit Seeds & Isabgol Boost Gut Health?