Beyond the gut-brain axis

Hearing about the gut-brain axis—the bidirectional health pathway that sends signals between the central nervous system (CNS) and enteric nervous system (ENS)—is becoming increasingly common. Now, as more people begin listening to their gut, it makes sense that scientists are exploring a slew of gut axes that highlight the connections or pathways between the microbiome of the gut and other major body systems such as the lungs, immune system and skin.

Consumers are beginning to understand a direct line connects the gut not just to the brain, but also to most of the other major organs in the body. And suppliers and manufacturers are in lockstep with solutions to help consumers meet their wellness goals.

Gut-immune response

Vicky Mak, ChildLife Essentials’ technical writer, hinted at a gut-brain-immune connection, saying the gut plays a pivotal role in supporting the mental and physical health of children. “The gut-brain axis is deeply intertwined with the immune system, which defends and protects the brain and gut from environmental substances; researchers have identified [this] … as the brain-immune-gut triangle.”¹

For starters, she said the first 12 months of life are the most important period of rapid brain development and dynamic microbial colonization of the gut.²

“In this regard, the gut acts like an ‘information superhighway.’ The microbiota in the gut regularly comes into contact with sites in the gut called the gut-associated lymphoid tissues (GALT), which contain many immune cells critical for supporting immune homeostasis, Mak said.³ “The GALT has important roles in protecting against pathogens and regulating nutrient intake.”

She further noted ongoing research suggests the gut-immune system is important in the development of autoimmune diabetes. “The gut-immune system has a key role in controlling insulin-specific immunity induced by dietary insulin,” she said.⁴ “Indications for aberrant function of the gut-immune system have been reported in type 1 diabetes, such as intestinal immune activation and increased intestinal permeability.”

For those new to gut-organ theory, a gut-immune axis may seem far-fetched. Imagine it as “a line connecting two distant entities to each other,” quipped Paul Schulick, a master herbalist and formulator at For the Biome. He maintained that a deeper understanding of the gut-immune relationship reveals the distance is closer than assumed.

“[The] immune system is virtually inseparable from your gut,” he explained. “The organs [have] a symbiotic relationship and communicate through receptors. They support each other’s functioning to support the health of the entire body. Your gut and your immune system need each other!”

Schulick likened the gut-immune dynamic to weeding a garden: “Your immune system supports the gut by helping it to maintain a balance of beneficial microbes (good bacteria), and by discriminating and eliminating harmful bacteria.”

Gut-skin axis

The phrase “healthier-looking skin starts from within” has never been truer. A more recent discovery than some of the other gut-organ relationships, the gut-skin axis links healthy skin to a balanced gut microbiome—the skin has its own microbiome, but it also appears to be influenced by the microbiome in the gut.

“There has been substantial research and data showing the direct relationship between the health of the gut and that of the skin,” reported Stuart Ashman, CEO of SkinBio Therapeutics.⁵ “Just think what happens when we eat foods that we’re allergic to and the resultant hives we see on the skin surface.”

According to Ashman, naturally reversing skin damage starts with healthy microbiota benefitted by select strains of “friendly bacteria” communicating through the gut-skin axis to reveal healthy skin.⁶

“The health of the gut is more interactive with the rest of the body than just sending information back and forth,” he noted. “I’d say it was more like a conductor in an orchestra in directing the body’s health.”

This excerpt was taken from a longer feature in the “Diverse microbiomes and digestive health” digital magazine. Click the link to access both.

Brenda Porter-Rockwell has a diverse background writing about nutraceuticals and healthy foods for a variety of trade and consumer publications, both print and online. She lives in North Carolina and can be reached at [email protected].

References

1 Szabo A and Rajnavolgyi E. “The Brain-Immune-Gut Triangle: Innate Immunity in Psychiatric and Neurological Disorders.” Curr Immunol Rev. 2013;9(4):241-248.

2 Ihekweazu FD and Versalovic J. “Development of the Pediatric Gut Microbiome: Impact on Health and Disease.” Am J Med Sci. 2018;356(5):413-423.

3 Mörbe UM et al. “Human gut-associated lymphoid tissues (GALT); diversity, structure, and function.” Mucosal Immunol. 2021;14(4):793-802.

4 Vaarala O. “The Gut Immune System and Type 1 Diabetes.” Ann N Y Acad Sci. 2002;958(1):39-46.

5 Sinha S et al. “The skin microbiome and the gut-skin axis.” Clin Dermatol. 2021;39(5):829-839.

6 Salem I et al. “The gut microbiome as a major regulator of the gut-skin axis.” Front Microbiol. 2018;9:1459.