Blautia and a little about the gut microbiome

Tags:

Interesting paper published in May 2024 by researchers from Nanjing University in China, looking at a possible probiotic candidate species Blautia wexlerae. Before we look at the study findings, I want to talk a little bit about some background details for context.

First, some definitions:

Prebiotic: Prebiotics are non-digestible food ingredients that promote the growth of many types of microorganisms in the intestines. They are typically types of dietary fiber that humans cannot digest, but they serve as food for gut bacteria.

Probiotic: Probiotics are live microorganisms that can be consumed in foods like yogurt, or fermented foods/drink (kombucha, kimchi, sauerkraut) or supplements.

Short chain fatty acids (SCFAs): Short chain fatty acids are fatty acids with fewer than six carbon atoms. They are produced when the beneficial bacteria in the gut ferment prebiotic fibers. Common and relevant SCFAs include acetate, propionate, and butyrate.

We know quite a lot about the general benefits of eating prebiotics, aka a high fiber diet.

The clinical importance of specific probiotics are not as well known, though we are learning more every day. It is not as simple as “Blautia (or Lactobacillus, or any other species) bacteria are healthy and good for you so you should consume more of them.”

You have probably heard the phrase, “The dose makes the poison.”. Similarly, with probiotics, the dose, along with the location, host immune system, and the other species of the microbiome, make the pathogen. E. coli is a normal component of the gut microbiome, but is a common cause for human disease such as urinary tract infections and can result in invasive infection. Streptococci and staphylococci are normal skin flora but are common sources of skin infections like cellulitis, abscesses, as well as invasive infections like bacteremia. These are obviously not bacteria that people are supplementing, but just serve as examples of where clinically, we must be careful what bacteria, the route, and the quantity, added to a potentially vulnerable organism like a human.

Probiotics may not be universally safe to supplement 1, may not provide lasting effects 2, or may result in varying but generally positive effects 3. What will it be in your or my specific circumstance? We do not fully know, yet, but the area is being heavily researched.

Blautia, it turns out, has some promise as a candidate for probiotic supplementation, but the trials showing safety and efficacy in different patient populations have not been done, yet. This genus of bacteria was not classified until 2008 4 and has since had some interesting research.

  • Blautia less common in the gut of obese children, and even less common in the presence of both obesity and insulin resistance. The authors go so far as to suggest that Blautia may reduce inflammation causally linked to insulin resistance 5.
  • Building on the above study, in 2022 Japanese researchers discovered that Blautia wexlerae oral supplementation in mice induced anti-inflammatory changes that decreased high-fat diet induced obesity and diabetes 6.
  • Blautia species negatively associated with visceral fat accumulation 7.
  • Blautia wexlerae improves obesity-associated male infertility in mice 8.
  • One year of gluten free diet in celiac patients correlates increased Blautia with decreased markers of disease 9.
  • Large vessel occlusion (big ischemic stroke) correlates with decreased Blautia abundance 10.
  • Decreased abundance of Blautia in children with autism spectrum disorder 11. “Notably, a specific strain of Blautia, Blautia stercoris MRx0006, demonstrated significant effects in ameliorating social deficits, repetitive behaviors, and anxiety-like behaviors in a mouse model of ASD, further highlighting the potential relevance of the Blautia genus in ASD pathophysiology.”
  • Blautia glucerasea was found in 4-fold higher prevalence in individuals without MetS 12.

And, the recent paper 13 that prompted this post looked at several factors that promote Blautia wexlerae growth, finding essentially that:

  • high fiber prebiotic foods and supplements promote B. wexlerae abundance

Gut microbes produce SCFAs by metabolizing prebiotics on the one hand, and the SCFAs produced on the other hand can in turn promote the growth of specific microbes in the gut. Peterson et al. found that acetate, isobutyrate, isovalerate, propionate, and valerate significantly increased the abundance of B. wexlerae. Overall, most of the prebiotics that are difficult to be digested and absorbed by the host can be used by B. wexlerae to promote its growth 13.

Suppose we want to try to favor Blautia growth without direct probiotic supplementation. What foods could we eat? The best way, currently, might be to consume a variety of high fiber foods, fruits and vegetables, which is consistent with existing advice for cultivation of a healthy microbiome - perhaps not a coincidence?

Let me know your thoughts/experiences in the comments. As always, be careful with unregulated supplements, and talk to your doctor for medical advice.

References

  1. Kothari, D., Patel, S. and Kim, S.-K. (2019) ‘Probiotic supplements might not be universally-effective and safe: A review’, Biomedicine & Pharmacotherapy, 111, pp. 537–547. Available at: https://doi.org/10.1016/j.biopha.2018.12.104. ↩︎

  2. Khalesi, S. et al. (2019) ‘A review of probiotic supplementation in healthy adults: helpful or hype?’, European Journal of Clinical Nutrition, 73(1), pp. 24–37. Available at: https://doi.org/10.1038/s41430-018-0135-9. ↩︎

  3. Barkhidarian, B. et al. (2021) ‘Probiotic Supplementation and Micronutrient Status in Healthy Subjects: A Systematic Review of Clinical Trials’, Nutrients, 13(9), p. 3001. Available at: https://doi.org/10.3390/nu13093001. ↩︎

  4. Liu, C. et al. (2008) ‘Reclassification of Clostridium coccoides, Ruminococcus hansenii, Ruminococcus hydrogenotrophicus, Ruminococcus luti, Ruminococcus productus and Ruminococcus schinkii as Blautia coccoides gen. nov., comb. nov., Blautia hansenii comb. nov., Blautia hydrogenotrophica comb. nov., Blautia luti comb. nov., Blautia producta comb. nov., Blautia schinkii comb. nov. and description of Blautia wexlerae sp. nov., isolated from human faeces’, International Journal of Systematic and Evolutionary Microbiology, 58(Pt 8), pp. 1896–1902. Available at: https://doi.org/10.1099/ijs.0.65208-0. ↩︎

  5. Benítez-Páez, A. et al. (2020) ‘Depletion of Blautia Species in the Microbiota of Obese Children Relates to Intestinal Inflammation and Metabolic Phenotype Worsening’, mSystems, 5(2), p. 10.1128/msystems.00857-19. Available at: https://doi.org/10.1128/msystems.00857-19. ↩︎

  6. Hosomi, K. et al. (2022) ‘Oral administration of Blautia wexlerae ameliorates obesity and type 2 diabetes via metabolic remodeling of the gut microbiota’, Nature Communications, 13(1), p. 4477. Available at: https://doi.org/10.1038/s41467-022-32015-7. ↩︎

  7. Ozato, N. et al. (2022) ‘Two Blautia Species Associated with Visceral Fat Accumulation: A One-Year Longitudinal Study’, Biology, 11(2), p. 318. Available at: https://doi.org/10.3390/biology11020318. ↩︎

  8. Zhong, Y. et al. (2024) ‘Effects of acetate-producing Blautia wexlerae on oxidative stress and NLRP3 inflammasome in obesity-associated male infertility’, Medical Microbiology and Immunology, 213(1), p. 11. Available at: https://doi.org/10.1007/s00430-024-00796-x. ↩︎

  9. Costigan, C.M. et al. (2024) ‘One year of gluten free diet impacts gut function and microbiome in celiac disease’. bioRxiv, p. 2024.06.20.599876. Available at: https://doi.org/10.1101/2024.06.20.599876. ↩︎

  10. He, P. et al. (2024) ‘Identifying gut microbiota with high specificity for ischemic stroke with large vessel occlusion’, Scientific Reports, 14(1), p. 14086. Available at: https://doi.org/10.1038/s41598-024-64819-6. ↩︎

  11. De Sales-Millán, A. et al. (2024) ‘Comprehensive Analysis of Gut Microbiota Composition and Functional Metabolism in Children with Autism Spectrum Disorder and Neurotypical Children: Implications for Sex-Based Differences and Metabolic Dysregulation’, International Journal of Molecular Sciences, 25(12), p. 6701. Available at: https://doi.org/10.3390/ijms25126701. ↩︎

  12. Witthöft, C. et al. (2024) ‘Gut microbiota composition and trimethylamine-N-oxide and methylamines in subjects with and without metabolic syndrome after ingestion of egg and meatballs’, Norsk tidsskrift for ernæring, 22(5). Available at: https://doi.org/10.18261/ntfe.22.5.116. ↩︎

  13. Rui, W. et al. (2024) ‘Potential Applications of Blautia wexlerae in the Regulation of Host Metabolism’, Probiotics and Antimicrobial Proteins [Preprint]. Available at: https://doi.org/10.1007/s12602-024-10274-8. ↩︎ ↩︎