Grow Younger, Live Longer

Gut Microbiome and Longevity: A Comprehensive Guide

ByOlena Santangeli, PhD
OnAugust 25, 2023
InNutrition

Maintaining a balanced gut microbiome is a key contributor to health, and the relationship between the gut microbiome and longevity is a burgeoning field of scientific exploration. — Image by katemangostar on Freepik

In a nutshell

Understanding the intricate relationship between the gut microbiome and longevity could unlock revolutionary strategies for enhancing human health and lifespan.
The gut microbiome, a diverse community of trillions of microbes, profoundly impacts our health and longevity.
Centenarians living beyond the age of 100 often exhibit a unique and diverse gut microbiota profile, pointing to a potential link between microbiome health and longevity.
A well-balanced diet rich in fiber, along with regular exercise, adequate sleep, and effective stress management practices, can contribute to a healthy gut microbiome.
Emerging evidence suggests that supplementation with probiotics and prebiotics might be a beneficial strategy to support gut microbiome health, promoting overall health and lifespan.

We all know that a balanced diet and regular exercise contribute to a long, healthy life. But did you know that trillions of little organisms living in your gut also play a significant role? Let’s dive into the fascinating world of the gut microbiome and its powerful impact on longevity.

The gut microbiome plays a pivotal role in the journey to robust health and graceful aging, with evidence emerging from scientific studies.¹ The gut microbiome, a vibrant ecosystem of trillions of microbes, including bacteria, viruses, and other microscopic entities, orchestrates an array of vital functions in our bodies.

Gut Microbiome in Aging: Lessons from Centenarians

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Centenarians, who live to or above the age of 100, often showcase a distinct composition of their gut microbiota. Interestingly, they possess a diverse microbiome, contributing to their extraordinary lifespan.

A seminal study by Biagi et al., illuminated that Italian centenarians harbored a unique gut microbial profile compared to younger elderly individuals.²

They discovered that certain beneficial bacteria are common in most people, but their numbers tend to decrease as we grow older. Meanwhile, less common bacteria become more abundant, and their relationships change.

In people who live to very old age (like semi-supercentenarians), the researchers found some unique changes. Even though their gut houses some potentially harmful bacteria, these ‘oldest of the old’ also have more of certain helpful bacteria (like Akkermansia, Bifidobacterium, and certain species from the Christensenellaceae family).

This research implicates the gut microbiome as a potential determinant of healthy aging and exceptional longevity.

The Mechanism: How Gut Microbiome Influences Aging

The complex interplay between the gut microbiome and longevity reminds us that our health is deeply interconnected with the microscopic life forms residing in our bodies. A vibrant ecosystem of trillions of microbes, our gut microbiome, is intricately linked to various aspects of our health, including immunity, metabolism, and even brain function.

Immune system regulation. The gut microbiome and our immune system are inextricably interconnected. They communicate and shape each other throughout our lives.³ As we age, changes in the gut microbiome can affect the immune system’s function, a phenomenon termed ‘immunosenescence’. ⁴ For instance, a decrease in beneficial bacteria can lead to chronic low-grade inflammation, an aging hallmark.

Metabolic Health. The gut microbiome also plays a critical role in metabolic health. Certain gut microbes help break down dietary fiber into short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate.⁵ These SCFAs serve several roles, from providing energy to intestinal cells, to regulating blood sugar and appetite.⁶ Research suggests that age-related changes in the microbiome can impact the production of SCFAs, potentially leading to metabolic disorders, which are prevalent in older populations.

Brain Health and Neurodegenerative Diseases. Emerging research highlights the ‘gut-brain axis’, a bidirectional communication system between the gut microbiota and the brain.⁷ Age-related alterations in the gut microbiome may influence brain health, potentially contributing to neurodegenerative diseases such as Alzheimer’s and Parkinson’s.⁸

Understanding these mechanisms provides insights into how nurturing a healthy gut microbiome might counteract age-associated health decline, offering the potential for extended healthspan and lifespan.

Supporting Your Gut Microbiome

Our gut microbiome, this bustling metropolis of microbes, is a living entity that responds dynamically to its environment. One of the most powerful tools we have to shape our gut microbiome and, consequently, our health and longevity, is our lifestyle choices. Here, we explore the most effective ways to support your gut microbiome.

Diet

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Diet is one of the fastest and most effective ways to alter the composition of your gut microbiome. Believe it or not, research shows that significant changes in the gut microbiota can occur within just a few days after dietary changes. ⁹

You can think of the food you eat as a type of information you’re sending to your body and to the trillions of microbes living in your gut. When you consume different foods, you’re essentially providing specific types of information that help certain microbes thrive and others to falter.

So, what kind of messages are you sending?

Eating a diet high in processed foods, added sugars, and unhealthy fats can provide ‘bad’ information, encouraging the growth of harmful bacteria. For instance, consuming too many sugary drinks or unhealthy snacks can lead to a less diverse microbiome and potentially contribute to inflammation and other health issues.¹⁰

Moreover, while our understanding of the intricate workings of the microbiome continues to grow, we are learning that several commonly used medications can significantly impact its health. These include acid blockers, antibiotics, laxatives, steroids, non-steroidal anti-inflammatory drugs (NSAIDs), oral contraceptives, and certain types of antidepressants and antipsychotics.¹¹

These medications can disrupt the balance of our gut microbiota, leading to dysbiosis, where harmful bacteria outpace the beneficial ones. This imbalance can potentially contribute to many health issues ranging from digestive disorders to mood swings, and even chronic diseases. As such, it is imperative to be mindful of these medications’ potential impacts on our gut health. Always discuss with your healthcare provider about the necessity of these medicines, potential alternatives, and strategies to mitigate their impact on your microbiome.

Food to nourish “bad” bugs

processed foods
added sugars
unhealthy fats
refined grains (especially wheat)
antibiotic drugs
hormones
laxatives
streroids
acid blockers
anti-inflammatory medicine

On the other hand, consuming a variety of plant-based foods rich in fiber and fermented food sends ‘good’ information, promoting the growth of beneficial bacteria.¹² Foods like colorful fruits, vegetables, whole grains, legumes, nuts, seeds, kefir, kimchi, miso, and sauerkraut provide the necessary nutrients that these ‘good bugs’ need to flourish.

How diverse should my diet be?

Try to include around 30 different plants in your meals over the course of a week. This could include vegetables, fruits, seeds, nuts, whole grains, legumes, herbs, and spices.

Studies suggest that including a high variety of different plants in your diet can significantly enhance the diversity and health of your gut microbiome. The magic number is around 30 different plants during the week.¹³

Consider the humble salad. Even a simple dish like this can be a medley of numerous plants. Lettuce forms the base, but then add some spinach, kale, and arugula for an extra punch of leafy greens. Sprinkle in chopped bell peppers, cucumbers, and cherry tomatoes for a burst of color and a host of different nutrients. Top it off with a handful of pumpkin seeds and sunflower seeds, and flavor with herbs like parsley or cilantro, and spices like turmeric or black pepper. Suddenly, you’ve created a dish that includes representatives from at least ten different plants!

But don’t stop there. Aim to incorporate an even wider variety of plants throughout your week. Experiment with different fruits, vegetables, whole grains, legumes, nuts, seeds, herbs, and spices. The more diverse your diet, the more diverse your microbiome, contributing to a healthier you.

Food to nourish “good” bugs

colorful fruits
vegetables,
whole grains
legumes
nuts, seeds
kefir
kimchi
miso
sauerkraut
apple cider vinegar
yogurt
pickled vegetables
tempeh

Thus, by thoughtfully choosing what we eat, we have the power to influence the balance of ‘good’ and ‘bad’ bacteria in our gut, supporting our overall health and longevity.

Fecal Microbiota Transplant

Image by KamranAydinov on Freepik

While diet provides a convenient and natural way to reshape our gut microbiome, medical science has developed a rather unconventional but highly effective method to change our microbiome composition rapidly: Fecal Microbiota Transplant (FMT).

FMT, as the name suggests, involves the transfer of fecal bacteria from a healthy donor into the gut of a recipient. The goal of FMT is to replace harmful bacteria with beneficial ones, thus restoring the balance of the gut microbiota.¹⁴

This procedure has gained attention due to its efficacy in treating recurrent Clostridioides difficile infections, a severe gut infection that becomes increasingly resistant to antibiotics.¹⁵ For patients suffering from this condition, FMT has often been a game-changer, offering a cure rate of more than 80%.¹⁶

Beyond treating infections, research is investigating the use of FMT for a range of other health conditions associated with gut microbiota imbalances, such as inflammatory bowel disease, obesity, and even neurological disorders.¹⁷

However, while FMT is a powerful tool, it’s essential to remember that it’s a medical procedure that comes with potential risks, and it should only be conducted under the supervision of a healthcare professional.

Longevity Practices to Affect Microbiome

Image by Drazen Zigic on Freepik

Adopting lifestyle habits known in the longevity community not only promotes health and longevity but also influences your gut microbiome. These practices range from physical activity and sleep to stress management and even certain longevity supplements.

Exercise

Physical exercise doesn’t just benefit your muscles and heart—it can also boost your gut microbiota health.¹⁸ Research has found that exercise can increase the diversity and stability of your gut microbiota.

Preclinical research also suggests that regular physical activity can encourage the growth of beneficial bacteria that produce short-chain fatty acids (SCFAs), compounds that play essential roles in maintaining gut and overall health.¹⁹

Sleep

The importance of adequate and quality sleep cannot be overstated. While it may not seem obvious, sleep and your gut microbiome are closely intertwined. Sleep deprivation or irregular sleep patterns can disrupt the balance of your gut bacteria, potentially leading to health issues.²⁰ Thus, regular, restful sleep is crucial for maintaining a healthy microbiome.

Stress Management

Chronic stress can upset your gut microbiota balance, leading to a condition known as dysbiosis.²¹ Techniques to manage stress, such as mindfulness, meditation, yoga, and deep-breathing exercises, can help preserve healthy gut microbiota. By promoting a state of calm and relaxation, these practices can contribute to gut microbiome health and longevity.

Longevity Supplements

Certain supplements known in the longevity community might also play a role in supporting gut microbiome health. For instance, berberine, a compound found in several plants, and is known for its ability to regulate blood sugar levels and improve insulin sensitivity. It has been shown to alter gut microbiota composition and exert anti-inflammatory and antimicrobial effects. In particular, it was selectively reducing the number of some negative bacteria, while increasing the number of bacteria that potentially produce beneficial compounds, such as short-chain fatty acids (SCFAs).²² Remember, before starting any new supplement regimen, it’s best to consult a healthcare provider.

On the other hand, pharmaceutical alternatives like metformin, often prescribed for similar health benefits as berberine, may not be as beneficial for the microbiome. Evidence suggests that metformin may impair the gut microbiome, potentially offsetting some of the benefits of healthy microbiota.²³ This is not to undermine the value of metformin for those who need it, but it’s a crucial aspect to consider in the broader discussion about gut health and longevity.

Supplements: Probiotics and Prebiotics

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When considering ways to support our gut microbiome, supplementation with probiotics and prebiotics is well worth exploring. This approach can act as a direct intervention to enrich our microbiota and foster a more diverse and balanced gut ecosystem.

Probiotics. Probiotics are live microorganisms that, when taken in appropriate amounts, offer health benefits. They’re often referred to as ‘good’ or ‘friendly’ bacteria, mirroring the beneficial bacteria naturally found in our bodies, particularly our gut.

These beneficial bacteria can help outcompete harmful bacteria, enhance the gut barrier function, and stimulate our immune system.²⁴ Probiotics are found in fermented foods such as yogurt, kimchi, sauerkraut, and kefir. Alternatively, they are available as dietary supplements, often containing a mix of different bacterial strains.

While the benefits of probiotics can be strain-specific and vary among individuals, some widely researched strains, such as those in the Lactobacillus and Bifidobacterium genera, have been associated with improved digestive health, enhanced immune response, and even mental health benefits.²⁵

Prebiotics. Prebiotics, on the other hand, are types of dietary fiber that serve as food for our gut bacteria. These non-digestible food components are fermented by our gut bacteria to produce beneficial compounds, including short-chain fatty acids, which have a range of health-promoting effects.

Sources of prebiotics include foods such as whole grains, bananas, onions, garlic, and artichokes. There are also specialized prebiotic supplements available, often containing fibers like inulin or fructooligosaccharides.

Safety of probiotics and prebiotics. While prebiotics and probiotics are generally considered safe, they are not without potential side effects, especially with long-term use. However, these are typically mild and digestive in nature. For example, some people may experience gas, bloating, or changes in bowel movements when starting to take these supplements.

Moreover, in very rare cases, especially in individuals with compromised immune systems or serious underlying health conditions, probiotics could potentially lead to more serious side effects, such as infections.²⁶

On the other hand, the potential benefits of taking probiotics and prebiotics can be particularly pronounced under certain circumstances. For instance, these supplements can be beneficial after a course of antibiotics. Antibiotics can significantly deplete the gut microbiota, including beneficial bacteria, and supplementation can help to restore this balance.²⁷

Similarly, individuals with digestive disorders like irritable bowel syndrome (IBS) may also benefit from certain probiotics. Clinical studies have shown that particular strains can help manage symptoms and improve the quality of life for people with IBS. ²⁸

Regardless of the situation, it’s important to remember that while probiotics and prebiotics can be part of a healthy lifestyle, they are not a substitute for a balanced diet and regular exercise. Also, always consult with a healthcare provider before starting any new supplement regimen.

Hydration

Free Stock photos by Vecteezy

An often undervalued element in supporting gut health is proper hydration. The role water plays in our digestive health and overall well-being is crucial, and it does so in several ways.

Firstly, water aids in digestion by helping to break down food so that your body can absorb the nutrients. It’s also vital in dissolving vitamins, minerals, and other nutrients from your food, which then get absorbed into your bloodstream and used by your body. Without adequate water intake, your body might struggle to extract all the goodness from the food you consume.

Additionally, water plays a key role in maintaining the health of the mucosal lining of the intestines. This lining forms a crucial barrier that helps to prevent harmful substances from leaking out of your intestines and into the rest of your body, a phenomenon known as “leaky gut.” If you’re dehydrated, this lining can become less effective, potentially leading to gut health issues.²⁹

How much water do I need per day?

At rest, consume approximately 8 oz (250 ml) every hour during the first 10 hours of your waking day. After this period, reduce the intake to about 5 oz (150 ml) per hour for the remaining hours. If you exercise, increase your water intake following the Galpin equation: your body weight (in pounds) / 30 = x oz to consume every 15 minutes.³⁰

Moreover, staying well-hydrated can prevent or alleviate constipation. Water softens stools and helps keep the digestive tract flowing smoothly, making it easier to pass waste. Chronic constipation can disrupt the balance of your gut microbiome and lead to other digestive health issues.

The ways to nurture a healthy gut microbiome are multifaceted, encompassing diet, lifestyle practices, and even medical procedures and supplements. These methods provide promising avenues for supporting gut microbiome health, promoting overall well-being, and potentially enhancing longevity. Our exploration of the gut microbiome and longevity would be incomplete without mentioning the importance of microbiome testing, which we’ve covered extensively in a separate piece, “Gut Microbiome Testing“.

Recap and final thoughts

To wrap things up, we’ve embarked on a journey through the intricate world of gut microbiome and longevity. We’ve learned about the vital role that our gut microbiota plays in our health, its connections to the aging process, and the various strategies we can adopt to support it.

We’ve delved into how diet, arguably the most influential factor, can swiftly shape our microbiome composition and contribute to our longevity. With our meals acting as information for our body, the choice between feeding beneficial or harmful gut bugs depends on our dietary habits.

We also touched on the potential of fecal microbiota transplants to quickly alter our gut microbiome, while highlighting other longevity practices that can positively impact our microbiome, such as regular exercise, proper sleep, stress management, and taking longevity-focused supplements like berberine.

Moreover, we’ve explored the role of probiotic and prebiotic supplements in fostering a healthier gut ecosystem, and the importance of hydration for maintaining digestive health and the integrity of our intestinal lining.

In essence, the science of gut microbiome and longevity provides fascinating insights into how we can potentially enhance our healthspan. With each choice we make, we’re influencing our gut microbiome and potentially our longevity. As we continue to explore this field, we’ll uncover more ways to promote healthy aging through our gut microbiome.

References

1
O’Toole PW, Jeffery IB. Gut microbiota and aging. Science. 2015 Dec 4;350(6265):1214-5. doi: 10.1126/science.aac8469. PMID: 26785481. PubMed Source
2
Biagi E, Franceschi C, Rampelli S, Severgnini M, Ostan R, Turroni S, Consolandi C, Quercia S, Scurti M, Monti D, Capri M, Brigidi P, Candela M. Gut Microbiota and Extreme Longevity. Curr Biol. 2016 Jun 6;26(11):1480-5. doi: 10.1016/j.cub.2016.04.016. Epub 2016 May 12. PMID: 27185560. PubMed Source
3
Belkaid Y, Hand TW. Role of the microbiota in immunity and inflammation. Cell. 2014 Mar 27;157(1):121-41. doi: 10.1016/j.cell.2014.03.011. PMID: 24679531; PMCID: PMC4056765. PubMed Source
4
Fulop T, Larbi A, Dupuis G, Le Page A, Frost EH, Cohen AA, Witkowski JM, Franceschi C. Immunosenescence and Inflamm-Aging As Two Sides of the Same Coin: Friends or Foes? Front Immunol. 2018 Jan 10;8:1960. doi: 10.3389/fimmu.2017.01960. PMID: 29375577; PMCID: PMC5767595. PubMed Source
5
Morrison DJ, Preston T. Formation of short chain fatty acids by the gut microbiota and their impact on human metabolism. Gut Microbes. 2016 May 3;7(3):189-200. doi: 10.1080/19490976.2015.1134082. Epub 2016 Mar 10. PMID: 26963409; PMCID: PMC4939913. PubMed Source
6
den Besten G, van Eunen K, Groen AK, Venema K, Reijngoud DJ, Bakker BM. The role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism. J Lipid Res. 2013 Sep;54(9):2325-40. doi: 10.1194/jlr.R036012. Epub 2013 Jul 2. PMID: 23821742; PMCID: PMC3735932. PubMed Source
7
Mayer EA, Nance K, Chen S. The Gut-Brain Axis. Annu Rev Med. 2022 Jan 27;73:439-453. doi: 10.1146/annurev-med-042320-014032. Epub 2021 Oct 20. PMID: 34669431. PubMed Source
8
Szandruk-Bender M, Wiatrak B, Szeląg A. The Risk of Developing Alzheimer’s Disease and Parkinson’s Disease in Patients with Inflammatory Bowel Disease: A Meta-Analysis. J Clin Med. 2022 Jun 27;11(13):3704. doi: 10.3390/jcm11133704. PMID: 35806985; PMCID: PMC9267426. PubMed Source
9
David LA, Maurice CF, Carmody RN, Gootenberg DB, Button JE, Wolfe BE, Ling AV, Devlin AS, Varma Y, Fischbach MA, Biddinger SB, Dutton RJ, Turnbaugh PJ. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014 Jan 23;505(7484):559-63. doi: 10.1038/nature12820. Epub 2013 Dec 11. PMID: 24336217; PMCID: PMC3957428. PubMed Source
10
Zinöcker MK, Lindseth IA. The Western Diet-Microbiome-Host Interaction and Its Role in Metabolic Disease. Nutrients. 2018 Mar 17;10(3):365. doi: 10.3390/nu10030365. PMID: 29562591; PMCID: PMC5872783. PubMed Source
11
Vich Vila, A., Collij, V., Sanna, S. et al. Impact of commonly used drugs on the composition and metabolic function of the gut microbiota. Nat Commun 11, 362 (2020). https://doi.org/10.1038/s41467-019-14177-z Source
12
Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017 Mar 4;8(2):172-184. doi: 10.1080/19490976.2017.1290756. Epub 2017 Feb 6. PMID: 28165863; PMCID: PMC5390821. PubMed Source
13
Daniel McDonald et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems, 2018; 3 (3): e00031-18 Source
14
Cammarota G, Ianiro G, Tilg H, Rajilić-Stojanović M, Kump P, Satokari R, Sokol H, Arkkila P, Pintus C, Hart A, Segal J, Aloi M, Masucci L, Molinaro A, Scaldaferri F, Gasbarrini G, Lopez-Sanroman A, Link A, de Groot P, de Vos WM, Högenauer C, Malfertheiner P, Mattila E, Milosavljević T, Nieuwdorp M, Sanguinetti M, Simren M, Gasbarrini A; European FMT Working Group. European consensus conference on faecal microbiota transplantation in clinical practice. Gut. 2017 Apr;66(4):569-580. doi: 10.1136/gutjnl-2016-313017. Epub 2017 Jan 13. PMID: 28087657; PMCID: PMC5529972. PubMed Source
15
Khoruts A, Sadowsky MJ. Understanding the mechanisms of fecal microbiota transplantation. Nat Rev Gastroenterol Hepatol. 2016 Sep;13(9):508-16. doi: 10.1038/nrgastro.2016.98. Epub 2016 Jun 22. PMID: 27329806; PMCID: PMC5909819. PubMed Source
16
Quraishi MN, Widlak M, Bhala N, Moore D, Price M, Sharma N, Iqbal TH. Systematic review with meta-analysis: the efficacy of fecal microbiota transplantation for the treatment of recurrent and refractory Clostridium difficile infection. Aliment Pharmacol Ther. 2017 Sep;46(5):479-493. doi: 10.1111/apt.14201. Epub 2017 Jul 14. PMID: 28707337. PubMed Source
17
Zhang F, Cui B, He X, Nie Y, Wu K, Fan D; FMT-standardization Study Group. Microbiota transplantation: concept, methodology and strategy for its modernization. Protein Cell. 2018 May;9(5):462-473. doi: 10.1007/s13238-018-0541-8. Epub 2018 Apr 24. PMID: 29691757; PMCID: PMC5960466. PubMed Source
18
Monda V, Villano I, Messina A, Valenzano A, Esposito T, Moscatelli F, Viggiano A, Cibelli G, Chieffi S, Monda M, Messina G. Exercise Modifies the Gut Microbiota with Positive Health Effects. Oxid Med Cell Longev. 2017;2017:3831972. doi: 10.1155/2017/3831972. Epub 2017 Mar 5. PMID: 28357027; PMCID: PMC5357536. PubMed Source
19
Denou E, Marcinko K, Surette MG, Steinberg GR, Schertzer JD. High-intensity exercise training increases the diversity and metabolic capacity of the mouse distal gut microbiota during diet-induced obesity. Am J Physiol Endocrinol Metab. 2016 Jun 1;310(11):E982-93. doi: 10.1152/ajpendo.00537.2015. Epub 2016 Apr 26. PMID: 27117007; PMCID: PMC4935139. PubMed Source
20
Benedict C, Vogel H, Jonas W, Woting A, Blaut M, Schürmann A, Cedernaes J. Gut microbiota and glucometabolic alterations in response to recurrent partial sleep deprivation in normal-weight young individuals. Mol Metab. 2016 Oct 24;5(12):1175-1186. doi: 10.1016/j.molmet.2016.10.003. PMID: 27900260; PMCID: PMC5123208. PubMed Source
21
Karl JP, Margolis LM, Madslien EH, Murphy NE, Castellani JW, Gundersen Y, Hoke AV, Levangie MW, Kumar R, Chakraborty N, Gautam A, Hammamieh R, Martini S, Montain SJ, Pasiakos SM. Changes in intestinal microbiota composition and metabolism coincide with increased intestinal permeability in young adults under prolonged physiological stress. Am J Physiol Gastrointest Liver Physiol. 2017 Jun 1;312(6):G559-G571. doi: 10.1152/ajpgi.00066.2017. Epub 2017 Mar 23. PMID: 28336545. PubMed Source
22
Zhang X, Zhao Y, Zhang M, Pang X, Xu J, Kang C, Li M, Zhang C, Zhang Z, Zhang Y, Li X, Ning G, Zhao L. Structural changes of gut microbiota during berberine-mediated prevention of obesity and insulin resistance in high-fat diet-fed rats. PLoS One. 2012;7(8):e42529. doi: 10.1371/journal.pone.0042529. Epub 2012 Aug 3. PMID: 22880019; PMCID: PMC3411811. PubMed Source
23
Forslund, K., Hildebrand, F., Nielsen, T. et al. Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota. Nature 528, 262–266 (2015). Source
24
Rijkers GT, de Vos WM, Brummer RJ, Morelli L, Corthier G, Marteau P. Health benefits and health claims of probiotics: bridging science and marketing. Br J Nutr. 2011 Nov;106(9):1291-6. doi: 10.1017/S000711451100287X. Epub 2011 Aug 24. PMID: 21861940. PubMed Source
25
Wallace CJK, Milev R. The effects of probiotics on depressive symptoms in humans: a systematic review. Ann Gen Psychiatry. 2017 Feb 20;16:14. doi: 10.1186/s12991-017-0138-2. Erratum in: Ann Gen Psychiatry. 2017 Mar 7;16:18. PMID: 28239408; PMCID: PMC5319175. PubMed Source
26
Doron S, Snydman DR. Risk and safety of probiotics. Clin Infect Dis. 2015 May 15;60 Suppl 2(Suppl 2):S129-34. doi: 10.1093/cid/civ085. PMID: 25922398; PMCID: PMC4490230. PubMed Source
27
McFarland LV. Meta-analysis of probiotics for the prevention of antibiotic associated diarrhea and the treatment of Clostridium difficile disease. Am J Gastroenterol. 2006 Apr;101(4):812-22. doi: 10.1111/j.1572-0241.2006.00465.x. PMID: 16635227. PubMed Source
28
Ford AC, Quigley EM, Lacy BE, Lembo AJ, Saito YA, Schiller LR, Soffer EE, Spiegel BM, Moayyedi P. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis. Am J Gastroenterol. 2014 Oct;109(10):1547-61; quiz 1546, 1562. doi: 10.1038/ajg.2014.202. Epub 2014 Jul 29. PMID: 25070051. PubMed Source
29
Blikslager AT, Moeser AJ, Gookin JL, Jones SL, Odle J. Restoration of barrier function in injured intestinal mucosa. Physiol Rev. 2007 Apr;87(2):545-64. doi: 10.1152/physrev.00012.2006. PMID: 17429041. PubMed Source
30
Andy Galpin “25 Minute Physiology” Source