The Second Brain and You

By: Makeeda Bandele-Asante

CP in Dietetics

Howard University

The gastrointestinal tract (GI), also called the gut, includes the esophagus, stomach, intestines, and supporting organs. These organs allow our bodies to digest and absorb food for growth, development, functionality, and immune health. As food components enter the bloodstream and carry nutrients throughout the body, a healthy gut is crucial to wellness. A healthy gut contains microorganisms and immune cells that fight off pathogens and infections. It also is able to communicate with the brain via nerves and hormones to maintain wellbeing.

Source: Banik, R. MD. Gut-Brain-Connection [Photograph]. Rudrani Banik.

Some experts refer to the gut as the second brain due to its integral function in sustenance, mood, and overall wellbeing. The 100 million nerve cells that line the GI tract are part of the enteric nervous system (ENS), which alludes to their activity in motor function, mucosal secretions, and endocrine function. Research has found that irritable bowel syndrome (IBS), diarrhea, and other upset stomach conditions are impacted by the GI signals sent to the central nervous system, which trigger mood alterations. Seeing that diet can impact the mental state, as we gain more understanding of the connection between the ENS and the central nervous system (CNS), we can improve mind-body therapies such as cognitive behavioral therapy and medical hypnotherapy.

Source: Florjanczyk, U. MScBMC. (2022) Endocrine system: Structure and function [Photograph]. Osmosis.

Typically, it is the immune system signals that activate communication with the brain so that the immune response is initiated. Pro-inflammatory cytokine proteins disperse throughout the brain tissue to target areas in response to infection by arranging critical host reactions. The neuroendocrine and autonomic nervous systems mediate innervation of lymphoid organs, immune cells, and neurological components to drive immune function.

Fermented foods are sometimes consumed to improve immune health. These foods are formulated with the help of enzymatic action of controlled microbial growth. This creates bioactive compounds, compounds that act to promote health. Fermentation is a metabolic process that initiates chemical changes as sugar molecules break down anaerobically, in the absence of oxygen. Microorganism activity extracts energy from the degraded organic nutrients to produce adenosine triphosphate (ATP), an energy molecule that obtains chemical energy for use in the cellular processes in all living things, from bacteria to humans. Microorganisms’ then convert the sugars into alcohol, lactic acid, carbon dioxide, and other gases.

Prebiotics are non-digestible, non-living plant fibers that serve as food for probiotics. Probiotics are living microorganisms that feed off prebiotics and flourish to balance gut flora. The action of probiotics on the gut microbiome can produce nutrients, such as vitamin K and B vitamins. Lactobacillus and Bifidobacterium are two common probiotic bacteria and are present in the fermented foods yogurt, cottage cheese, kimchi, miso soup, and tempeh. Probiotics can also reduce harmful compounds such as cyanobacteria algae, dead tissue, and E. coli.

Source: Probiotics: What You Need To Know. [Photograph]. NIH.

Historically, food fermentation was used as a preservation and decontamination technique. The process also can alter the texture, aroma, and taste of foods, like in olives. This process improves antioxidant activity as it impacts the bioavailability of nutrients, as well as levels of flavonoids and phenolic compounds.

Good gut health supports immune function, digestion, and absorption, feel good hormones, and encourages growth and development across all life cycles. Feel good hormones act on body tissues and organs to impact function and feeling. Also considered neurotransmitters, these hormones include dopamine, serotonin, endorphins, and oxytocin and are present in functional foods. Functional foods are foods with health-promoting components that are commonly referred to as superfoods and medical foods. Whole, minimally processed, enriched, and fortified foods can be functional. Oatmeal, berries, fatty fish like salmon, and beans are examples of functional foods. Nutrition professionals can encourage patients to eat these functional foods to improve health.

Source: It's not off, it's fermented--microorganisms can preserve foods.

An example of a functional and fermented food is kefir. Kefir is a fermented milk drink made from kefir grains and is the most popular researched fermented food. It has been connected with lactose malabsorption benefits and H. pylori eradication.

There is limited evidence of the effectiveness of most fermented foods for GI health due to low quality and absent studies. Milder GI discomfort, reductions in lipid profiles, and antimicrobial activity has been found due to fermented food consumption. More studies should be performed on human subjects in addition to the present microbiology studies.

References

Deizenne, N. M. (2021). Dieting for Success: What Baseline Gut Microbiota Can Tell You About Your Chances of Losing Weight. Gastroenterology. https://www.gastrojournal.org/article/S0016-5085(21)00408-X/fulltext?referrer=https%3A%2F%2Fpubmed.ncbi.nlm.nih.gov%2F

Dimidi, E., Cox, S. R., Rossi, M., & Whelan, K. (2019). Fermented foods: Definitions and characteristics, impact on the gut microbiota and effects on gastrointestinal health and disease. NCBI. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723656/

Kapp, J. M., & Sumner, W. (2018). Kombucha: A systematic review of the empirical evidence of human health benefit. Annals of Epidemiology. https://www.sciencedirect.com/science/article/pii/S1047279718307385?via%3Dihub

The brain-gut connection. Johns Hopkins Medicine. (2021). https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection

The President and Fellows of Harvard College. (2021). The gut-brain connection. Harvard Health. https://www.health.harvard.edu/diseases-and-conditions/the-gut-brain-connection#:~:text=A%20troubled%20intestine%20can%20send,GI)%20system%20are%20intimately%20connected.

Wollman, E. E., & Dantzer, R. (2003). Relationships between the brain and the immune system. Journal de la Societe de biologie. https://pubmed.ncbi.nlm.nih.gov/12910622/#:~:text=The%20communication%20pathways%20that%20link,represented%20mainly%20by%20proinflammatory%20cytokines.