The Gut + Mind Connection

WRITTEN BY MELANIE FLORES AND DR. SWATHI

How many times do you remember thinking of a meal you are about to eat and suddenly your stomach begins growling and gurgling? You may have also noticed that during times of mental stress you experience digestive problems or feel “butterflies in your stomach.” This phenomenon provides evidence for “gut-mind connection.” This term refers to the link between your gut microbiota or microbiome in your gut, and how it relates to your mental wellbeing. This article will explore ways to improve your microbiome and current research on the gut-mind connection.

What Is the Gut Microbiome?

The term microbiome refers to all of the ‘good’ microorganisms (bacteria, viruses, and fungi) that live in the gastrointestinal (GI) tract. These microorganisms exist naturally within our bodies, and provide us with a mutually beneficial relationship. The ratio of bacterial cells versus human cells in our body is estimated to be 1:1. With this in mind, it makes sense why our mind and overall functioning as a human would be so affected by these microorganisms that live in our digestive tract. The food we eat, our environment, supplements, and antibiotics can affect our gut microbiome. Gut microbiota have been shown to provide us with energy, regulate our immune system and emotional health,  and protect us against pathogens. If our gut microbiota is dysregulated, also referred to as dysbiosis, then it is to be expected that the systems that our microbiota regulates would also be out of whack. This is precisely why there has been a recent interest in how to improve our gut-microbiota and how it relates to the mental health crisis in America.

How to Improve our Gut Microbiome

• Eat a variety of nutrient-dense foods
• Veggies, fruits, beans, lentils
  
• Eat fermented foods
• Yogurt, sauerkraut, kombucha, kimchi, kefir, tempeh
• Consume foods with prebiotics
• Oats, barley, mushrooms, garlic, onions
• Take a quality probiotic supplement–do your research, not all probiotics are quality!
• Get 7-9 hours of high quality sleep every night
• Manage your stress levels

The Gut-Mind Connection

This term refers to the ways that the health of balance of our gut microbiome can directly affect our mental health. The gut and the brain are known to be connected both physically and chemically. The vagus nerve is the nerve that physically connects the gut and brain in your body; this is the nerve in part to blame for digestive problems that arise from stressful situations. Neurotransmitters are the chemicals that are responsible for connecting your gut and mind; neurotransmitters are chemicals that are known to regulate brain functioning such as emotions and focus. The bacteria that live in our gut actually produce neurotransmitters, especially serotonin and GABA. Serotonin is known to play a role in depression and the GABA neurotransmitter is involved in the manifestation of anxiety. Those with gastrointestinal irritation such as diarrhea and constipation may experience significant emotional distress due to the gut-mind connection. These findings could also explain why those with GI disorders, such as irritable bowel syndrome (IBS) and Ulcerative Colitis (UC), suffer from mental illnesses at a higher proportion than the average healthy population.  Numerous studies are now exploring the exact link between gut and health and mental wellness.

Current Research

Numerous studies in the last 5 years have explored the link between gut and mental health. Read on to see a few below.

A 2021 randomized, double-blind, placebo-controlled study explored the benefit of improving gut health on cognitive functions in older adults–63 healthy adults over the age of 65 were either given placebo or a quality probiotic pill daily for the course of 12 weeks. Gut bacteria that caused inflammation were reduced in the probiotic group and mental flexibility improved along with their stress levels.

Another 2021 randomized controlled trial evaluated the effects of probiotics on stress levels, depression, anxiety, and sleep among 156 healthy adults under the age of 65 over the course of eight weeks. The probiotic group had a significant reduction in depressive symptoms at 8 weeks and anxiety symptoms at 4 weeks. They also had improvements in their sleep quality.

A 2020 randomized controlled trial explored the correlation between improving mental health and gut health. Patients aged 60-85 that were diagnosed with mild cognitive impairment completed mindful awareness practices weekly for 3 months and then monthly for 6 months. Neuropsychological assessments, inflammatory markers, and gut microbiota profiles were tested in the patients. The results showed that as the cognition of patients improved that there was a direct correspondence in changes in their microbiota.

Final Takeaway

Research seems to show that there is a definite link between gut health and the mind. We should all strive to take care of our gut health to ensure we are setting ourselves up for optimal mental and cognitive wellness.

References

1. Kim CS, Cha L, Sim M, Jung S, Chun WY, Baik HW, Shin DM. Probiotic Supplementation Improves Cognitive Function and Mood with Changes in Gut Microbiota in Community-Dwelling Older Adults: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. J Gerontol A Biol Sci Med Sci. 2021 Jan 1;76(1):32-40. doi: 10.1093/gerona/glaa090. PMID: 32300799; PMCID: PMC7861012.
2. Lee HJ, Hong JK, Kim JK, Kim DH, Jang SW, Han SW, Yoon IY. Effects of Probiotic NVP-1704 on Mental Health and Sleep in Healthy Adults: An 8-Week Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. 2021 Jul 30;13(8):2660. doi: 10.3390/nu13082660. PMID: 34444820; PMCID: PMC8398773.
3. Khine WWT, Voong ML, Ng TKS, Feng L, Rane GA, Kumar AP, Kua EH, Mahendran R, Mahendran R, Lee YK. Mental awareness improved mild cognitive impairment and modulated gut microbiome. Aging (Albany NY). 2020 Dec 9;12(23):24371-24393. doi: 10.18632/aging.202277. Epub 2020 Dec 9. PMID: 33318317; PMCID: PMC7762482.
4. Thursby E, Juge N. Introduction to the human gut microbiota. Biochem J. 2017 May 16;474(11):1823-1836. doi: 10.1042/BCJ20160510. PMID: 28512250; PMCID: PMC5433529.

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This article was edited by Dr. Swathi and was written by Element Apothec Scientific Communications Intern, Melanie Flores. She is a Doctor of Pharmacy (PharmD) student at Oregon State University and Oregon Health & Science University College of Pharmacy in Portland, Oregon.