• ↑ Carbohydrate, vegetable protein, and calories, iron, magnesium, potassium, vitamin C, & calcium

• ↓ Animal protein, & sodium

Intake of High-Fermented-foods diet Arm 🧫 :

• ↑ Animal protein (by virtue of eating more fermented foods like yogurt, kefir, etc.)

(Wastyk, H. C. et al., Cell, 2021)

• Of which extends to the underlying interplay between the intestinal barrier & the immune system (Conlon, A and Bird, A. R., Nutrients, 2014; Rinninella, E et al., Best Pract Res Clin Gastroenterol, 2023).

Lifestyle shifts following ‘westernization’ has led to a significant rise in....

• Dysbiosis

• Metabolic (i.e., diabetes) & non-communicable chronic diseases (NCCDs)

• Inflammatory markers

• Body Mass Index (BMI)

• Reduced microbial taxa (diversity) & Markers of host health

(Wastyk, H. C. et al., Cell, 2021)

🥦After High-fiber diet intervention: No diversity increase.

Due to:

• Short 10-week intervention is too hurried for microbiota reconstruction*

• Modern excessive sanitation measures (e.g. overuse of food chemical sanitizers) reducing bacterial diversity & exchanging

• Insufficient gut bacteria cultivation requiring simultaneous ingestion of fiber-rich foods & desired bacteria

• Caucasian genetic deficiency of certain bacterial species that Caucasian subjects lost some bacteria that can metabolize glycans.

*microbiota reconstruction: change in modeling of microbiota diversity, density & composition (i.e. various species)

🧀After High-fermented-food diet intervention: there is an increase in gut microbiota diversity & decrease in inflammatory proteins synthesis & NCCDs incidence (Wastyk, H. C. et al., Cell, 2021).

⭐️Final Participant Characteristics:

(Analysis used (n=18) in each arm)

• Average BMI 25 ± 4 kg/m²

• Average age 51 ± 12 years

• 73% Female

• 81% Caucasian

  (Wastyk, H. C. et al., Cell, 2021)

🦠Construction of mechanistic models: to investigate the causality between diet and host response = enabling global health improvement and health burden alleviation (Wastyk, H. C. et al., Cell, 2021).

⭐️VARIABLES:

*Collected stool (microbiota metabolic output, function, and composition) and blood samples (immune system markers) (Wastyk, H. C. et al., Cell, 2021)

• Primary Outcome Variable: Cytokine Response Score (CRS)

• Secondary Outcome Variable: Change in gut microbiome composition/diversity

⭐️DIET:

*High fiber/fermented food consumption increased every two weeks.

High Fiber Diet:

Vegetables, nuts, grains, fruits, seeds, etc.,

• Baseline: Mean 21.5 ± 8.0g/day

• Maintenance: Mean 45.1 ± 10.7g/day

High Fermented-Foods Diet:

Fermented vegetables, cottage cheese, vegetable brine, kombucha, fermented non-alcoholic beverages, etc.,

• Baseline: Mean 0.4 ± 0.6g/day

• Maintenance: Mean 6.3 ± 2.9g/day

(Wastyk, H. C. et al., Cell, 2021)

⏳Short study duration (10 weeks) cannot explore long-term efficacy, safety & stability.

🔕No control group cannot exclude impacts of confounding factors.

👩🏼Limited single subjects which are mainly healthy Caucasian women around age 51 (Wastyk, H. C. et al., Cell, 2021).

• Producing microbiota-accessible carbohydrates (MACs)--benefits metabolism of microbiota taxa (Wastyk, H. C. et al., Cell, 2021)

• Increasing microbiome richness/diversity (increased beneficial bacterial taxa like that of Akkermansia, Bifidobacterium, Lactobacillus) (Howard, E. J. et al., J Nutr, 2024)

• Lessening low-density lipoprotein cholesterol concentrations within the blood (Sidju, S. R. K. et al., Nutrients, 2023).

• Enabling bacterial fermentation → Short-chain fatty acids (i.e., butryrate, propionate, acetate) = enhancing metabolic homeostasis = colonic gut peptide release (i.e., glucagon-like peptide-1 (GLP-1)) (Howard, E. J. et al., J Nutr, 2024)

• Microbiota possessing distinct functionalities depending on fiber viscosity, type, & solubility (Howard, E. J. et al., J Nutr, 2024).

==> I.e., High viscosity, β-Glucan (soluble-fiber) from oats = enhanced glucose homeostasis

==> I.e., Low viscosity, dextrin (soluble-fiber) from wheat = enhanced insulin sensitivity

• Modifying immune system function via metabolites = Reduces local & systemic means of inflammation (Wastyk, H. C. et al., Cell, 2021)

Exemplified by how in-vivo mice models with high-fiber diets defended against myocardial infarction—stopped unfavorable remodeling and diminished infarct size (Zhao, J et al., Front Microbiol, 2022).

• Microbial fermentation alters food properties—converts phenolic compounds + complex carbohydrates → bioactive metabolites (i.e., SCFA))—boosting immune function & response (Stiemsma, L et al., J Nutr, 2020)

==> More microbial metabolites like tryptophan (for serotonin), polyphenolic compounds (for bioavailability), and bile acids (for metabolism)) (Balasubramanian, R et al., Neurosci Biobehav Rev, 2024)

• Pathway aid (gut-to-brain information communication/relay) (Balasubramanian, R et al., Neurosci Biobehav Rev, 2024)

• Gut microbiome diversity (Wastyk, H. C. et al., Cell, 2021)

• Nutrionally rich & environmentally sustainable alternative (i.e., protein-rich legume fermentation with lactic acid bacteria (LAB) OVER that of animal meat) for novel strains of probiotics (Valentino, V et al., Microb Biotechnol, 2024).

• Anti-nutrient reduction (Dimidi, E et al., Nutrients, 2019), Anti-microbial peptides

• Gut barrier maintenance & pH modification

• Biogenic amines (Dimidi, E et al., Nutrients, 2019)

• Probiotic effects (metabolic pathway reprogramming) (Dimidi, E et al., Nutrients, 2019)

Exemplified by how consuming kefir (a type of fermented food) can eradicate Helicobacter pylori, and malabsorption of lactose (Dimidi, E et al., Nutrients, 2019).

1. "Baseline": 3-Week Pre-Intervention

2. "Ramp": 4-Week Ramp Phase (progressive increase in respective diet (arm) intake)

3. "Maintenance": 6-Week Maintenance Phase (consistent consumption of respective diet (arm) at high levels)

4. "Choice": 4-Week Choice Period (respective diet (arm) level to the wanted extent of participants)

(Wastyk, H. C. et al., Cell, 2021)

⭐️ IMPORTANT NOTE:

*Participants did not increase consumption of food constituting the opposing arm. And, varied (no consistent subcategories) in types of fermented/fiber food consumed (Wastyk, H. C. et al., Cell, 2021).

Exemplified in a random control trial involving patients with ulcerative colitis:

• Anti-inflammatory diets in combination with fecal microbiota transplantations (FMT) exhibited greater results--better long-term remission maintenance--compared to that of standard (medical) treatment (Rinninella, E et al., Best Pract Res Clin Gastroenterol, 2023).

Highlighting the potential for human gut microbiota modulation (by diet) against disease. And, as each nutrient can possesses a distinct/certain effect on the gut microbiota, there is a rising interest in investigating the benefits of certain dietary combinations, patterns, and bases (Rinninella, E et al., Best Pract Res Clin Gastroenterol, 2023).

→ High-fermented food vs. high plant-based fiber.

1. Allan, S. M., & Rothwell, N. J. (2001). Cytokines and acute neurodegeneration. Nature Reviews Neuroscience, 2(10), 734–744. https://doi.org/10.1038/35094583

2. Balasubramanian, R., Schneider, E., Gunnigle, E., Cotter, P. D., & Cryan, J. F. (2024). Fermented foods: Harnessing their potential to modulate the microbiota-gut-brain axis for mental health. Neuroscience and biobehavioral reviews, 158, 105562. https://doi.org/10.1016/j.neubiorev.2024.105562

3. Caffrey, E. B., Sonnenburg, J. L., & Devkota, S. (2024). Our extended microbiome: The human-relevant metabolites and biology of fermented foods. Cell Metabolism, 36(4), 684–701. https://doi.org/10.1016/j.cmet.2024.03.007

4. Cantarel, B. L., Coutinho, P. M., Rancurel, C., Bernard, T., Lombard, V., & Henrissat, B. (2009). The carbohydrate-active enzymes database (CAZy): An expert resource for glycogenomics. Nucleic Acids Research, 37(Database issue), D233–D238. https://doi.org/10.1093/nar/gkn663

5. Chen, L., Liu, B., Ren, L., Du, H., Fei, C., Qian, C., Li, B., Zhang, R., Liu, H., Li, Z., & Ma, Z. (2023). High-fiber diet ameliorates gut microbiota, serum metabolism and emotional mood in type 2 diabetes patients. Frontiers in Cellular and Infection Microbiology, 13. https://doi.org/10.3389/fcimb.2023.1069954

6. Chen, Y.-R., Zheng, H.-M., Zhang, G.-X., Chen, F.-L., Chen, L.-D., & Yang, Z.-C. (2020). High Oscillospira abundance indicates constipation and low BMI in the Guangdong Gut Microbiome Project. Scientific Reports, 10(1), 9364. https://doi.org/10.1038/s41598-020-66369-z

7. Conlon, M., & Bird, A. (2014). The Impact of Diet and Lifestyle on Gut Microbiota and Human Health. Nutrients, 7(1), 17–44. https://doi.org/10.3390/nu7010017

8. Cotillard, A., Kennedy, S. P., Kong, L. C., Prifti, E., Pons, N., Le Chatelier, E., Almeida, M., Quinquis, B., Levenez, F., Galleron, N., Gougis, S., Rizkalla, S., Batto, J.-M., Renault, P., ANR MicroObes Consortium, Dore, J., Zucker, J.-D., Clement, K., & Ehrlich, S. D. (2013). Dietary intervention impact on gut microbial gene richness. Nature, 500(7464), 585–588. https://doi.org/10.1038/nature12480

9. De Filippo, C., Cavalieri, D., Di Paola, M., Ramazzotti, M., Poullet, J. B., Massart, S., Collini, S., Pieraccinim G.,   Lionetti, P. (2010). Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa. Proceedings of the National Academy of Sciences, 107(33), 14691–14696. https://doi.org/10.1073/pnas.1005963107

10. Delannoy-Bruno, O., Desai, C., Castillo, J. J., Couture, G., Barve, R. A., Lombard, V., Henrissat, B., Cheng, J., Han, N., Hayashi, D. K., Meynier, A., Vinoy, S., Lebrilla, C. B., Marion, S., Heath, A. C., Barratt, M. J., & Gordon, J. I. (2022). An approach for evaluating the effects of dietary fiber polysaccharides on the human gut microbiome and plasma proteome. Proc Natl Acad Sci USA, 119(20). https://doi.org/10.1073/pnas.2123411119

11. Derrien, M., Belzer, C., & de Vos, W. M. (2017). Akkermansia muciniphila and its role in regulating host functions. Microbial Pathogenesis, 106, 171–181. https://doi.org/10.1016/j.micpath.2016.02.005

12. Dimidi, E., Cox, S. R., Rossi, M., & Whelan, K. (2019). Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease. Nutrients, 11(8), 1806. https://doi.org/10.3390/nu11081806

13. Granado-Serrano, A. B., Martin-Gari, M., Ssnchez, V., Riart Solans, M., Berdun, R., Ludwig, I. A., Rubio, L., Vilaprinyo, E., Portero-Otin, M., & Serrano, J. C. E. (2019). Faecal bacterial and short-chain fatty acids signature in hypercholesterolemia. Scientific Reports, 9, 1772. https://doi.org/10.1038/s41598-019-38874-3

14. Hamad, I., Cardilli, A., Côrte-Real, B. F., Dyczko, A., Vangronsveld, J., & Kleinewietfeld, M. (2022). High-Salt Diet Induces Depletion of Lactic Acid-Producing Bacteria in Murine Gut. Nutrients, 14(6), 1171. https://doi.org/10.3390/nu14061171

15. Hamamah, S., Amin, A., Al-Kassir, A. L., Chuang, J., & Covasa, M. (2023). Dietary Fat Modulation of Gut Microbiota and Impact on Regulatory Pathways Controlling Food Intake. Nutrients, 15(15), 3365. https://doi.org/10.3390/nu15153365

16. Howard, E. J., Meyer, R. K., Weninger, S. N., Martinez, T., Wachsmuth, H. R., Pignitter, M., Auñon-Lopez, A., Kangath, A., Duszka, K., Gu, H., Schiro, G., Laubtiz, D., & Duca, F. A. (2024). Impact of Plant-Based Dietary Fibers on Metabolic Homeostasis in High-Fat Diet Mice via Alterations in the Gut Microbiota and Metabolites. The Journal of nutrition, 154(7), 2014–2028. https://doi.org/10.1016/j.tjnut.2024.05.003

17. Ionita-Mindrican, C.-B., Ziani, K., Mittitelu, M., Oprea, E., Neacsu, S. M., Moroson, E., Dumitrescu, D.-E., Rosca, A. C., Draganescu, D., & Negrei, C. (2022). Therapeutic benefits and dietary restrictions of fiber intake: A state of the art review. Nutrients, 14(13), 2641. https://doi.org/10.3390/nu14132641

18. Jeyaram, K., Lahti, L., Tims, S., Hans, Gelder, van, Willem, Smidt, H., & Zoetendal, E. G. (2025). Fermented foods affect the seasonal stability of gut bacteria in an Indian rural population. Nature Communications, 16(1). https://doi.org/10.1038/s41467-025-56014-6

19. Klimenko, N. S., Tyakht, A. V., Popenko, A. S., Vasiliev, A. S., Altukhov, I. A., Ischenko, D. S., Shashkova, T. I., Efimova, D. A., Nikogosov, D. A., Osipenko, D. A., Musienko, S. V., Selezneva, K. S., Baranova, A., Kurilshikov, A. M., Toshchakov, S. M., Korzhenkov, A. A., Samarov, N. I., Shevchenko, M. A., Tepliuk, A. V., & Alexeev, D. G. (2018). Microbiome responses to an uncontrolled short-term diet intervention in the frame of the citizen science project. Nutrients, 10(5), 576. https://doi.org/10.3390/nu10050576

20. Leeuwendaal, N. K., Stanton, C., O’Toole, P. W., & Beresford, T. P. (2022). Fermented Foods, Health and the Gut Microbiome. Nutrients, 14(7), 1527. https://pubmed.ncbi.nlm.nih.gov/35406140/

21. Le Chatelier, E., Nielsen, T., Qin, J., Prifti, E., Hildebrand, F., Falony, G., Almeida, M., Arumugam, M., Batto, J.-M., Kennedy, S., Leonard, P., Li, J., Burgdorf, K., Grarup, N., Jorgensen, T., Brandslund, I., Nielsen, H. B., Juncker, A. S., Bertalan, M., Levenez, F., ... Pedersen, O. (2013). Richness of human gut microbiome correlates with metabolic markers. Nature, 500(7464), 541–546. https://doi.org/10.1038/nature12506

22. Li, C.-J. (Ed.). (2014). Butyrate: Food sources, functions and health benefits. Nova Science Publishers.

23. Liu, S., Li, E., Sun, Z., Fu, D., Duan, G., Jiang, M., Yu, Y., Mei, L., Yang, P., Tang, Y., & Zheng, P. (2019). Altered gut microbiota and short chain fatty acids in Chinese children with autism spectrum disorder. Scientific Reports, 9, Article 287. https://doi.org/10.1038/s41598-018-38218-9

Results → hypothesis NOT supported ❌

📚 Previous literature has often linked high fiber diets to increased microbial diversity, based on both interventional animal studies and long term associations in humans (Sonnenburg, E., et al., Nature, 2016; De Filipo, C., et al., PNAS, 2010; Le Chatelier, E., et al., Nature, 2013). However, this was not consistent with the current study.

∴ Over the course of the intervention, there was no change in alpha diversity

1. Similar change of gut microbiota & inflammation condition in response to high-fiber diet: There was a study investigating the high-fiber diet effects on type II diabetes participants that high-fiber foods increased the density, diversity and composition of the participants’ gut microbiota and decreased the inflammation condition, which were similar to the results of our selected paper.

2. Small sample size: Chen’s research also adoped small sample size with only n=9 for treatment group and n=8 for control group, reducing the statistical power.

3. Short study duration (4 weeks of high-fiber-diet treatment) cannot explore long-term effectiveness, safety & stability.

4. Limited single subjects with only type II diabetes patients whose glycosylated hemoglobin (HbA1c) measurements are 6.5-12%, excluding those who suffered from other chronic diseases (including type I diabetes, severe mental disorders, liver cirrhosis, cancers, cardiovascular diseases, etc.) and ingested prebiotics and antibiotics three months ago. Maybe the subjects’ age, gender and race could be further clarified for reference.

Contrast:

1. Presence of control group: providing the baseline level for comparing the differences in effects (e.g. blood sugar & lipid levels) and eliminating the confounding factors’ impacts.

2. Different subjects: type II diabetes patients whose HbA1c measurements are 6.5-12%, which is different from our selected paper (subjects are mainly healthy Caucasian women around age 51 (Wastyk, H. C. et al., Cell, 2021)).

3. Metabolic improvement: However, in addition to the microbiota composition and immune change, the researchers found that participants’ blood sugar and lipid homeostasis were ameliorated with rised level of insulin and dropped level of triglyceride.

4. Mental improvement: They also explored the participants’ mood response to the dietary change, showing the improved anxiety and depression status.

5. Multiaspect understanding: The results enhance the understanding of diet alteration effects on microbiota composition, inflammation, metabolic and meatal health among chronic-diseased people, demonstrating a multiaspect appreciation of diet-indued health improvement.

6. Extensive enhancement of global health: A wider global health guidance can be proposed in terms of high-fiber diet recommendation for both type II diabetes patients and healthy people, and global health may be largely improved subsequently (Chen et al., Front Cell Infect Microbiol, 2023)

(Wastyk, H. C. et al., Cell, 2021).

They inferred → it was bacteria already present that grew

∴ Since no new bacterial species were detected, and there was an increase in microbial proteins per gram stool (total bacterial biomass), it is likely bacteria already present in the microbiome that is growing.

Method → metagenomic sequencing 🧬

📚 Previous studies have also reported similar findings. For example, one study investigating fiber rich snacks found that increased consumption led to a significant increase in CAZyme gene abundance (Delannoy-Bruno, O., et al., Proc Natl Acad Sci USA_, 2022).

∴ This suggests it was bacteria adept at fiber degradation that increased in abundance

*(↓) indicates a reduction in beneficial microbial bacterium that were previously dominant in pre-'Westernized' diets.

(Statovci, D et al., Front Immunol, 2017)

• Fatty processed/domesticated meat, red-meat (↓Streptococcus bovis/gallolyticus) (Severino, A et al., Best Pract Res Clin Gastroenterol, 2024)

• Sugar/artificial sweeteners (↓Lactobacillus, ↓ Bifidobacteria) (Ruiz-Ojeda, F. J. et al., Adv Nutr, 2019), corn-derived fructose syrup

• Salt (↓ Akkermansia) (Hamad, I et al., Nutrients, 2022)

• Refined grains (↓Faecalibacterium)

• Saturated fat (↓ Bacteroidetes) (Hamamah, S et al., Nutrients, 2023)

Overall, this diet is significantly LOW in fiber, fermented food, nutrient dense/diverse foods, fruits, whole grains, unsaturated fat, vegetables, omega-3 fatty acids, etc.,.

• Cytokine response from baseline to end-of-intervention was not statistically different in both treatment arms.

  ⇨ Simultaneously, NO changes in overall general health, perceived stress, well-being, fatigue, physical activity levels or cognition throughout the study (Wastyk, H. C. et al., Cell, 2021).

🔍 Hypothesis: Long-term changes in diet (e.g. chronic nutrient deficiencies) can alter immune responses unfavourably, impairing cytokine production and response (Rossio, J. L. 1999). The short duration of the study may not have been long enough to see beneficial effects on the immune system (e.g. increased cytokine production, etc).

Summary in the high-fibre arm 🍌 :

↑ in the genus Lachnospira;

↑ stool softness (as per GSRS).

Summary in the high-fermented-food arm 🥛 :

↓  in the genus Lachnospira;

↓ inflammatory markers;

↑ microbiota diversity;

↑ initial bloating (as per GSRS; subsided by the end of the maintenance phase).

(Wastyk, H. C. et al., Cell, 2021)

🔗 This reinforces the idea that the gut microbiome is altered by factors outside of just dietary habits.

• This is concurrent with studies that show that a complex microbial community can be altered by many factors like lifestyle, genetics and even mode of delivery at birth (Wen, L., & Duffy, A., J. Nutr, 2017; Stiemsma et al., J. Nutr, 2020).

(Wastyk, H. C. et al., Cell, 2021)

🔗 Link: Unno et al.'s study in healthy women between ages 20-24 shows that the ingestion of fermented-milk leads to a significant increase in Firmicutes (longitudinally), relative to Bacteroidetes (Unno, T. et al., JDS, 2015). These results mirror Wastyk et al.'s.

(Wastyk, H. C. et al., Cell, 2021)

🔍 Hypothesis: A study explains that even when fermented foods are injested by the host, they themselves become further fermented and interact with the GI tract in a novel way (Caffrey, E. B. et al., Cell Metab, 2024). This may lead to the creation and detection of new bacterial taxa.

• (3) starch-degrading and (5) plant degrading

🔗 Link & Further Study: A recent study of a rural Indian population in Manipur –a self-declared fermented-foods eating population (consuming mostly fermented soybeans and milk)– have gut microbiomes extremely abundant in Prevotella. Prevotella shows, amongst all Bacteroidota (in the phylum), the lowest potential to produce CAZymes and short-chain fatty acids (SCFAs) in the gut (Jeyaram, K. et al., Nat Commun, 2025). Thus, consuming a high-fermented-food diet may have increased Prevotella in the gut of participants. Further investigation is required to asses the existence of a correlation or causation.

Cytokine profiling → ↓ in 19/93 cytokines

• Longitudinal decreases in pro-inflammatory cytokines, such as IL-6,  CXCL10,  IL-18, etc.

(Wastyk, H. C. et al., Cell, 2021)

🔍 Link & Hypothesis: Fermented foods may have a neuroprotective effect, by way of immune system modulation. Further supported by a moderately-well established relationship in the literature; a fermented-food diet leads to an increase in brain-derived neurotropic factor (BDNF; enhancing neuronal health and differentiation) and a decrease in cognitive decline symptoms and inflammation (Porras-García, E. et al., Front Nutr, 2023).

(Wastyk, H. C. et al., Cell, 2021)

Found mixed results →

• Butyrate levels did not increase ❌

• Three BCFAs decreased ✅

  • Isobuytric and isovaleric acid

    • Previously associated with hypercholesterolemia (Granado-Serrano, A., et al., Scientific Reports, 2019)

  • Valeric acid

    • Previously associated with autism spectrum disorder (Liu, S., et al., Scientific Reports, 2019)

📚 Previous studies on dietary fiber interventions have often reported increases in butyrate. For instance, one study observed elevated fecal butyrate levels following fiber consumption (So, D., et al., American Journal of Clinical Nutrition, 2018). This was not consistent with the current study.

📚 Previous studies also have also linked dairy as sources of BCFAs (Taormina, V., et al., Nutrients, 2020).

🔍 Note → As participants reported a decrease in animal protein consumption, its possible the observed decrease in BCFAs can be due to this dietary change.

∴ Metabolic output shifted, but results were mixed.

Hypothesized → fiber intake exceeded the microbiome's fermentation capabilities

Method → analyzed stool carbohydrates using HP - LC

Results → positive correlation found between fiber intake and stool carbohydrate levels ✅

📚 Previous literature also suggests when fiber intake is increased rapidly or in large amounts, the microbiome may not have the enzymatic capabilities to ferment all of it, possibly leading to digestive symptoms, such as bloating and diarrhea (Ionita-Mindrican, C., et al., Nutrients, 2022). As stool carbohydrates increased as fiber intake increased, this was consistent with the study's findings.

∴ Participants' microbiomes were unable to fully break down the increased fiber.

• O-link (multiplex proteomic platform) to measure circulating cytokines

• CyTOF (single-cell mass cytometry) to measure cell frequency & endogenous signalling

• Flow cytometry to evaluate signalling capacity

Participants grouped based on changes in steady-state immune system activation →

1. High inflammation group

2. Low inflammation group I

3. Low inflammation group II

🔍 Note → Variation in fiber subtypes consumed may have contributed to differences in immune responses.

∴ Researchers identified three distinct immune response groups, suggesting participants differed in how their immune system reacted to the high fiber intervention.

Found →

• No significant difference between high inflammation and low inflammation I groups ❌

• Low inflammation II showed significantly higher alpha diversity ✅

∴ The low inflammation group II had significantly higher alpha diversity as baseline, suggesting it may be associated with a more regulated or less inflammatory immune response profile.

→ Like, therapeutic strategies combatting pathogenesis (Wastyk, H. C. et al., Cell, 2021)!

• Coprococcus, Ruminococcus, Oscillospira, and Anaerostipes were more prevalent in low inflammation groups

  • These taxa have previously been linked to higher quality of life, better metabolic health, and increased butyrate production (Valles-Colomer, M., et al., Nature Microbiology, 2019; Klimenko, N., et al., Nutrients, 2018; Chen, Y., et al., Scientific Reports, 2020; Li, Butyrate: Food Sources, Functions and Health Benefits, 2014).

• Akkermansia was more abundant in the high inflammation group

  • Previously been positively associated with metabolic health (Derrien, M., et al., Microbial Pathogenesis, 2017)

📚 Previous literature investigating fiber rich diets have also reported similar taxa. For example, a recent study examining fiber rich snacks made from peas and oranges observed a significant increase of Lachnospiraceae and Ruminococcus (Delannoy-Bruno, O., et al., Proc Natl Acad Sci USA, 2022).

∴ Low inflammation groups were enriched in beneficial taxa linked to gut health and butyrate production, while high inflammation participants a different microbial profile. This suggests that people can respond differently to fiber depending on their individual microbiota.