What you eat is how you feel!

• Sai Lavanya Patnala, Intern, Apollo Institute of Medical Sciences and Research, Hyderabad

Introduction

Remember when Amitabh Bachchan said, “ Motion se hi emotion” in the movie, Piku?! Turns out there is ample evidence that this is absolutely true. There has been an established relationship between one’s gut health and mental health. The composition of gut microbiota influenced by your lifestyle and food habits has been known to have an impact in improving several mental health conditions backed by recent research.

What is the Microbiota-gut-brain axis(MGB Axis)?

The microbiome plays an important role in the programming of the hypothalamic-pituitary-adrenal (HPA) axis early in life, and stress reactivity over the life span. (1)

Healthy gut function has been linked to normal central nervous system (CNS) function. Hormones, neurotransmitters and immunological factors released from the gut are known to send signals to the brain either directly or via autonomic neurons. The existence of the gut-brain axis was proposed in the landmark study by Sudo and colleagues that discovered the impaired stress response in germ-free mice. (2)

The link between the brain and gut microbiota has been termed the MGB axis, and preclinical studies indicate that dysbiosis (dysregulation of the microbiota) influences anxiety and stress behaviors, suggesting that the MGB could influence the risk of disease, including anxiety and mood disorders. (1)

Why is the MGB axis important?

The bidirectional link between the brain, gut, and microbiome has come to the forefront of the medical research community in the past few years. The growing amount of evidence substantiating this link indicates it will be a valuable area for future medical and nutritional practice, and research.

The key relationship between the gut microbiota and diet continues throughout life. Diet alterations can have significant impact on the gut bacterial composition in as little as 24 hours. When the human microbiome is challenged with changes in diet, stress, or antibiotics, the physiology of the normal microbiome undergoes change. Inflammation of the GI tract places stress, possibly through the involvement of corticotrophin releasing factor (CRF) and its receptors (1), on the microbiome through the release of cytokines and neurotransmitters. A dysbiotic state leads to increased intestinal permeability and allows contents such as bacterial metabolites and molecules to leak into systemic circulation, a phenomenon named leaky gut syndrome.(2)

The role of the gut microbiome in mental health has been of great interest in the past years, with several breakthroughs happening in the last decade. Its implications in several psychiatric disorders, namely anxiety, depression, autism and schizophrenia have been noted in rodents, as well as human studies. (3)

What can you do to improve your gut health?

PROBIOTICS

The utility of probiotics is questionable as no form is currently regulated by the FDA, including natural sources such as yogurt, kefir, or sauerkraut. Patients may be more likely to use these natural sources of probiotics both due to increased accessibility as well as the cultural use of these foods in daily recipes. Recent research has shown that the use of fermented foods in diets confer gastrointestinal and cognitive benefits. However, until more evidence behind the use of probiotics as therapy for anxiety and depressive disorders is available, probiotics in any form cannot be considered a reliable therapy to anxiety and depressive disorders as compared to psychiatric medications. Furthermore, gender differences as well as comorbidities such as obesity, lifestyle, and tobacco and alcohol use may impact the overall benefit of probiotics.(2)

WALNUTS

A clinical trial done by researchers at University of South Australia found that daily consumption of walnuts prevented the significant changes in mental health-related scores (AQoL-8D & MHC) and scores of stress and depression (DASS21), thus walnuts may alleviate the negative effects of academic stress on mental health in university students. Academic stress had a negative effect on metabolic biomarkers such as total protein and albumin since these were decreased during the university examination period. Daily consumption of walnuts increased total protein and albumin levels, thus may protect against the negative effects of academic stress on metabolic biomarkers.(4)

CONCLUSION

The bidirectional communication between the central nervous system and gut microbiota, referred to as the microbiota-gut-brain axis (MGB Axis), has been of significant interest in recent years. This phenomenon has been recognized as a potential therapeutic target for mental illness. Whilst the scientists across the globe find a way to put the axis to complete use, we can make slight changes in our daily diet by incorporating more probiotic foods and research-proven walnuts.

REFERENCES

1. Malan-Muller S, Valles-Colomer M, Raes J, Lowry CA, Seedat S, Hemmings SMJ. The Gut Microbiome and Mental Health: Implications for Anxiety- and Trauma-Related Disorders. OMICS. 2018 Feb;22(2):90-107. doi: 10.1089/omi.2017.0077. Epub 2017 Aug 2. PMID: 28767318.
2. Clapp M, Aurora N, Herrera L, Bhatia M, Wilen E, Wakefield S. Gut microbiota’s effect on mental health: The gut-brain axis. Clin Pract. 2017 Sep 15;7(4):987. doi: 10.4081/cp.2017.987. PMID: 29071061; PMCID: PMC5641835.
3. Andrioaie IM, Duhaniuc A, Nastase EV, Iancu LS, Luncă C, Trofin F, Anton-Păduraru DT, Dorneanu OS. The Role of the Gut Microbiome in Psychiatric Disorders. Microorganisms. 2022 Dec 9;10(12):2436. doi: 10.3390/microorganisms10122436. PMID: 36557689; PMCID: PMC9786082.
4. Herselman MF, Bailey S, Deo P, Zhou X-F, Gunn KM, Bobrovskaya L. The Effects of Walnuts and Academic Stress on Mental Health, General Well-Being and the Gut Microbiota in a Sample of University Students: A Randomised Clinical Trial. Nutrients. 2022; 14(22):4776. https://doi.org/10.3390/nu14224776