How to protect yourself from COVID-19: Gut Health

Woman Healthy Gut Image

Introduction

In this article, I outline how maintaining a healthy gut may help protect you against severe COVID-19.

The good news is that you can readily improve your gut health using the four simple interventions outlined below.

What is a healthy gut?

Your gut is a complex ecosystem consisting of millions of bacteria, collectively known as your gut microbiome, which can weigh up to 2 kg!

A healthy gut microbiome plays a critical role in maintaining your health (1). Briefly, a healthy gut microbiome provides the following beneficial functions (1):

  • Improved metabolic health
  • Produce critical bacterial metabolites, such as short-chain fatty acids (SCFAs), helping to support your immune system
  • Preserves the structural integrity of the gut mucosal barrier
  • Protects you against pathogens

In contrast, having an unhealthy gut microbiota is called dysbiosis, a state characterized by a less diverse and less stable bacterial population that may include pathogenic bacteria  (1).

Dysbiosis has many adverse consequences, such as poor metabolic health and a compromised gut mucosal barrier. In addition, the reduced gut barrier integrity caused by dysbiosis allows bacteria and toxins to enter your bloodstream, triggering an inflammatory response that may exacerbate the risk of severe COVID-19 (2).

The Gut-Lung Axis

There is increasing evidence that your gut microbiome affects your lung health (3). For example, gut dysbiosis contributes to asthma, tuberculosis, and lung cancer (3). However, how the lungs and gut communicate is still not fully understood.

Nevertheless, a distributed ‘mucosal immune response’ exists where the gut microbiome influences your immune response at distal mucosal sites, such as the lung. Notably, several studies indicate that dysbiosis can increase the severity of respiratory virus infections, such as influenza (4).

Thus, maintaining your gut health may protect you against the effects of respiratory viruses.

The link between Dysbiosis and Severe COVID-19

Several risk factors for severe COVID-19, such as age, diabetes, and hypertension, are associated with gut dysbiosis (5). In addition, SARS-CoV-2 infected patients who developed COVID-19 disease have significantly different gut microbiomes compared with asymptomatic SARS-CoV-2 patients (2).

Furthermore, new evidence suggests that suffering a SARS-CoV-2 gut infection can lead to dysbiosis (6). Moreover, the dysbiosis caused by COVID-19 disease may persist long after the SARS-CoV-2 infection has cleared, as shown in a recent study that demonstrated dysbiosis persisting in COVID-19 survivors 3 months after their infection had cleared (7).

Thus dysbiosis may be a risk factor for COVID-19 and long COVID.

Why Gut Health is Important for Avoiding COVID-19

To summarize the story so far, actively maintaining your gut health may be protective against COVID-19 for the following reasons.

  1. A healthy gut reduces inflammation, which could help you avoid a severe inflammatory response to a SARS-CoV-2 infection.
  2. Gut dysbiosis makes other respiratory virus infections, such as influenza, more severe. Therefore, gut dysbiosis may increase the risk of severe COVID-19 after SARS-CoV-2 infection.
  3. Associations between gut microbiota composition and inflammatory markers in patients with COVID-19 suggest that an unhealthy gut microbiome increases the risk of COVID-19 (2).
  4. COVID-19 can cause dysbiosis, which can last several months after SARS-CoV-2 infection (7). Therefore, COVID-19-induced dysbiosis may increase the risk of long-COVID (2, 7).

Thus, although researchers have not yet formally established the link between gut health and COVID-19 in randomized clinical trials, there are good reasons for you to believe that maintaining a healthy gut helps protect you against COVID-19.

Four Ways to Maximise Your Gut Health

Fortunately, there are safe and effective ways for you to improve and maintain your gut health.

1. Diet

The best and most important intervention to improve and maintain your gut health is by following a healthy diet (8, 9). In a nutshell, maintaining a nutrient-rich diet with plenty of fiber supports a diverse gut microbiome that helps keep you healthy (9).

We recommend two diet options, the MIND diet and the Mediterranean diet, which provide a large proportion of mixed vegetables and unsaturated fats to support a healthy gut microbiome.  

However, any diet low in saturated fat and high in plant material, particularly fiber, supports a healthy gut microbiome (9).

2. Prebiotics

Nutrients that preferentially support the growth and proliferation of beneficial bacteria in your gut are called prebiotics (10). Prebiotics are present in leek, asparagus, chicory, Jerusalem artichoke, garlic, artichoke, onion, and banana (10).

Of course, you can readily supplement your diet with prebiotics or consume prebiotic-fortified foods and supplements to help maintain a healthy gut biome (10).

3. Probiotics

A probiotic is a ‘live micro-organisms that, when administered in adequate amounts, confer a health benefit on the host‘ (11). Some established positive effects of probiotic consumption are protection against gastroenteritis, improved lactose tolerance, stimulation of the immune system, and reductions in blood lipids (10).

In humans, the most common forms of probiotics are fermented milk products (e.g., yogurt) and freeze-dried preparations of beneficial bacteria in capsules (10).

4. Exercise

Multiple, carefully controlled animal studies have shown that aerobic exercise changes the gut microbiome and increases the production of bacterial metabolites that increase the gut barrier’s integrity and support healthy immune function (12). In addition, studies in humans support the idea that regular exercise supports a healthy gut microbiome.

However, there are several caveats to using exercise for improving your gut health.

First, the effects of exercise on your gut microbiome disappear if you stop exercising (12). Second, exercise has the most beneficial effects for improving gut microbiome health in lean individuals (12). Finally, although a short duration of light-to-moderate aerobic training may improve your gut microbiome, a longer duration at a higher intensity is required to induce significant improvements in your gut microbiome composition (12).

Thus, lean individuals who train hard for extended periods experience the most significant improvements to their gut health (12).

Take-Home Message

Observations that an unhealthy gut correlates with severe COVID-19, combined with the known protective effects of a healthy gut microbiome against infection, argue that gut health is an essential factor in protecting yourself from severe COVID-19.

Fortunately, a healthy diet, prebiotic and probiotic supplements, and aerobic exercise are all safe and effective options for improving your gut health.

Gut Health Against Covid Infographic

References and Further Reading

1.            K. A. Lee et al., The gut microbiome: what the oncologist ought to know. Br J Cancer,  (2021).

2.            Y. K. Yeoh et al., Gut microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19. Gut 70, 698-706 (2021).

3.            K. F. Budden et al., Emerging pathogenic links between microbiota and the gut-lung axis. Nat Rev Microbiol 15, 55-63 (2017).

4.            V. L. Ngo, A. T. Gewirtz, Microbiota as a potentially-modifiable factor influencing COVID-19. Curr Opin Virol 49, 21-26 (2021).

5.            N. S. Magalhães, W. Savino, P. M. R. Silva, M. A. Martins, V. F. Carvalho, Gut Microbiota Dysbiosis Is a Crucial Player for the Poor Outcomes for COVID-19 in Elderly, Diabetic and Hypertensive Patients. Front Med (Lausanne) 8, 644751 (2021).

6.            G. L. V. de Oliveira, C. N. S. Oliveira, C. F. Pinzan, L. V. V. de Salis, C. R. B. Cardoso, Microbiota Modulation of the Gut-Lung Axis in COVID-19. Front Immunol 12, 635471 (2021).

7.            Y. Tian et al., Gut Microbiota May Not Be Fully Restored in Recovered COVID-19 Patients After 3-Month Recovery. Front Nutr 8, 638825 (2021).

8.            I. Rowland et al., Gut microbiota functions: metabolism of nutrients and other food components. Eur J Nutr 57, 1-24 (2018).

9.            S. Anand, S. S. Mande, Diet, Microbiota and Gut-Lung Connection. Front Microbiol 9, 2147 (2018).

10.          G. E. Walton, G. R. Gibson, K. A. Hunter, Mechanisms linking the human gut microbiome to prophylactic and treatment strategies for COVID-19. Br J Nutr 126, 219-227 (2021).

11.          C. Hill et al., Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506-514 (2014).

12.          L. J. Mailing, J. M. Allen, T. W. Buford, C. J. Fields, J. A. Woods, Exercise and the Gut Microbiome: A Review of the Evidence, Potential Mechanisms, and Implications for Human Health. Exerc Sport Sci Rev 47, 75-85 (2019).

Acknowledgments

Images provided by MangoStar_Studio and Tijana87

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Yoga Nidra for Better Sleep

Disrupted sleep increases anxiety and depression. Yoga Nidra is an effective method that has helped many people overcome insomnia.

Beautiful Woman Running On Treadmill

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Emerging research shows that low-intensity cardio is the best way to improve your metabolic and cardiovascular health.

Strong bones, strong brain.

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Regular exercise releases osteocalcin from your bones. Once in circulation, osteocalcin enters your brain to support learning and memory.