Can just six days of eating oats, milk, and water can change your intestine microbiom?

According to a recently published study CriticismThe answer is more complicated than expected. Researchers from KU Lewaven and collaborative institutions intervened a tightly controlled diet, known as “porridge studies”, to check if restricting the diversity of food can induce convergence in intestinal microbyota in individuals. Surprisingly, while the diets of the participants became almost uniform, their microbiom did not follow the suit. This exposes the importance of individual reactions and outlines the limits of a size-fit-all approaches in microbyota-targeted diet interventions.

The 21-day study followed 18 healthy adults from Flanders, Belgium. It was structured in three stages: a 7-day base with habitual diet, 6-day intervention where participants only consumed oat flakes, whole milk, and still water, and 8-day follow-ups where the normal diet resumed. Daily stool samples and weekly blood draws were collected, enabled quantitative Microbiom The 16s RRNA was paired with profileing flow cytometry via gene sequencing. Participants also maintained a detailed food diary, allowing researchers to connect diet intake with microbial and metabolic results. In particular, microbiome analysis increased the data accuracy for an estimated 2-day interval between ingestion and eggsion.

major findings

• Dietary convergence

The intervention reduced food intake variety significantly. The analysis confirmed a sharp decline in diet variation during the 6-day oat-only phase. Macronutrient intake also declined, which reduced calories by 31.5%, and a significant decrease in consumption of fat, protein and carbohydrates. Interestingly, the consumption of fiber increased due to the OAT-based diet.

• Microbiome did not converge individuals

One of the most amazing conclusions of the study was the lack of differences in the difference Intestine microbiotaInstead of becoming more similar, the microbiom profile remained separate and in some cases, even more vary. The impact of dietary intervention on genus-tier microbiome variation was 3.4%, but with a striking inter-16.42%. This reduces long-held perception that similar diet input will achieve uniform microbial results and supports the approach that host-specific factors such as genetics, baseline microbyota, and metabolic abilities dominate reactions to diet modulation.

• Shift to potential dysbiotic enterotype

A remarkable change was observed in the microbial community structure. The prevalence of bacteroids 2 (BACT2), during intervention, an enterotype-bar associated with dysbiosis-disinteal dysbiosis, while the more stable bacteroids 1 (BACT1) community declined. These changes were reversed after the participants resumed their normal diets. This Bact2 dominance coincides with a marked drop HoroscopeA butyrate-productive genus is known for its anti-inflammatory properties. Given the low microbial diversity and its cooperation with the inflammatory states, the transient increase of Bact2 increases concerns about the health effects of such restrictive diet.

• Microbial load and diversity decreased

Without changes in stool moisture or transit time, the feacal microbial load fell more than 30% during intervention. It aligns with low calorie intake and resonates pre -conclusions, which reduces bacterial biomass under calorie ban. In addition, the overall microbiom diversity-such that is measured by the Shannon index, dropped significantly during intervention, a pattern that is correlated with low mature and flexible microbial ecosystems.

• Individual microbiome reacted uniquely

Despite the group-level trends, individuals gave a very different reply to the same diet. Some showed marked changes in microbial composition, while others remained relatively stable. The authors attempted to identify future factors, such as gender or baseline microbyota variety, but no clear predictions emerged after improvement for several tests. This unexpectedness confirms the complexity of the host -microbiota interaction and suggests that individual symptoms, instead of diet, run microbial changes. Personal nutrition may be necessary to achieve targeted microbiom modulation.

Interpretation and implication

The findings of this study have challenged the spontaneous belief that diet simplification should naturally lead convergence in microbial communities. Instead, they depict the importance of pre -existing microbial states in shaping the reactions to individual microbota and environmental changes. This highlights: (1) individual diet on universal recipe: even under tightly controlled diet conditions, individuals show unique microbial reactions. Future interventions must consider individual basic assessments to direct dietary recommendations; (2) Caution in using enterotypes as a biomarker: While Bact2 is paired with dysbiosis and disease, its transient presence in healthy individuals suggests caution when fixed here or interotypes as a pathological markers here; (3) Beyond calories and macronutrients: The study supports the concept of “succession related maturity” of microbiom, where microbial development is not only shaped by consuming nutrients, but also by substrate variety and transit time. These factors can be equally important as calorie content in shaping intestine health.

Finally, the “porridge study” underlines that radical cuts in dietary diversity also do not necessarily do not necessarily do not have uniformity in intestine microbyota. Instead, the human microbiom displays flexibility and personality, which is ruled by complex host -microbe global. While the dietary convergence increased the prevalence of potential dysbiotic community type and low microbial variety, the overall effect was minor and highly variable among individuals. These insights are essential for the design of future microbiom-targeted interventions, which must be responsible for personal variability and ecological references.