Eating only wild foods transforms your gut microbiome in just a few weeks, study shows

Eating only wild foods transforms your gut microbiome in just a few weeks, study shows

An all-wild diet triggers a microbial overhaul of the gut that promotes fiber bacteria and remodels the ecosystem in a way that lasts even after returning to regular foods.

In a study recently published in the journalScientific reportsResearchers examined how a diet consisting entirely of wild foods affects the composition, structure and persistence of changes in the gut microbiome (GM) in modern humans.

background

What happens when we stop eating something cultured or processed? Many urban populations consume bulk, sugar, and low-fiber diets that can disrupt GM balance. In contrast, “traditional” populations that consume fiber-rich, minimally processed foods tend to have greater microbial diversity, which is associated with better immunity and lower inflammation.

Previous research shows that dietary changes can reshape GM, but most studies remain within the confines of industrial diets based on domesticated foods. Because early humans relied on wild foods, studying this pattern can offer insights into our evolutionary biology. Further research is needed to validate these results in different populations.

About the study

Venison vs. supermarket meat: Meals included leaner wild game such as venison and ocean fish, which have different fat profiles compared to domesticated meat, a subtle driver of microbiome shifts.

A healthy adult male aged 46 years followed an eight-week self-monitoring dietary protocol divided into three phases: two weeks of a normal diet, four weeks of a wild food diet only, and two weeks returning to a normal diet.

The wild foods available in Northern Europe in the fall were gathered and prepared using primitive techniques such as open cooking and grinding stones. The participant maintained his usual lifestyle and lived in his own home and isolated dietary influence from other variables. He was an experienced forager and his health and well-being were monitored daily, with all food intake meticulously recorded.

Stool samples were collected daily and stored at −20 °C. The microbial deoxyribonucleic acid (DNA) was extracted, and the V3-V4 regions of the 16S ribosomal ribonucleic acid (rRNA) gene were sequenced using the Illumina Miseq platform. Amplicon sequence variants (ASVs) were determined using divisive amplicon denoising algorithm 2 (DADA2) and taxonomically classified using the Systematic Initiative for Large-Scale Verification of Alignments Database (SILVA).

The species-level analysis used the genomes from the Earth's soil microbiomes (GEM). Co-highance networks were constructed using Kendall's correlation and visualized in Cytoscape to identify keystone taxa.

Functional potential was inferred using phylogenetic study of communities through reconstruction of unobserved states (Picrust2) and Kyoto Encyclopedia of Genes and Genomes (KEGG) ortholog analysis. The comparative analysis included microbiomes from hunter-gatherer, rural and urban-industrial populations.

Statistical tests, including Kruskal-Wallis and Wilcoxon Rank-Sum, were applied, and adjustments for multiple tests were made using the Benjamini-Hochberg method with a false discovery rate of ≤0.05.

Study results

Primitive Prep, Modern Twist: While most foods were cooked over open fires or processed with stones, the study allowed for a unique meat grind, highlighting how even small technological conveniences could influence nutritional experiments.

While eating the food-only diet, the participant's GM underwent significant changes in structure and variety. Initial microbial communities were dominated by typical western-associated taxa such as Bacteroidaceae, Ruminococcaceae and Bifidobacteriaceae.

When the wild food diet began, there was a significant shift with a decrease in these groups and an increase in families such as Lachnospiraceae, Butyricicoccacaceae, and Streptococcaceae. Notably, Bifidobacteriaceae and Rikenellaceae did not return to pre-diet levels even after the participant resumed their regular diet. The family Akkermaniaceae, in particularAkkermansia muciniphilaincreased significantly in the period following food weight, a finding related to metabolic benefits.

The wild food diet also resulted in a significant weight loss of 4kg over four weeks with the greatest loss in the first week. The participant reported boredom and limited food choices, contributing to reduced calorie intake. When returning to a normal diet, two kilograms were quickly regained. This weight loss has been attributed in part to calorie restriction and the monotony of available foods.

A gradual increase in microbial alpha diversity was observed from the pre-wild food weight period to the post-food weight period (P < 0.05), indicating that the intervention had a sustained effect on microbiome structure even after its conclusion. Keystone species also moved.

Before the intervention,Faecalibacterium prausnitziiplayed a central role in the microbial network. During the wild food phase,Blautiaand its associated taxa, known for fiber degradation and fatty acid (short-chain fatty acid) production, dominated the network.

Six microbial co-abundance groups (CAGs) were identified. These groups came to be reorganized based on the nutritional phase, indicating a functional composition of the ecosystem.Faecalibacterium prausnitziiPresentRuminococcus bicirculansAndBlautiaappeared as important influencers at different times. The post-kindergarten period showed an intermediate configuration, with some characteristics of the pre-kindergarten phase and others, such as the persistence of certain onesBlautiaAndCoprococcus is comingGroups that reflect a lasting impact of the intervention.

Accidental detox diet: Plants from former farmland may have introduced microbes capable of breaking down persistent herbicides like atrazine, suggesting an unintentional “training” for the gut.

Despite this transformation, no new or ancestral “old friend” taxa such asTreponemaorPrevotellaappeared. The changes were driven solely by shifts in abundance among preexisting taxa and not by the introduction of new species. This finding suggests that even significant dietary changes may not be sufficient to reconstitute the microbial taxa of ancestral Anams without additional environmental stress.

Functional predictions showed increased abilities for starch degradation and amino acid biosynthesis during the wild food period, likely in response to a diet high in chestnuts and acorns but low in animal proteins. Functional analysis also showed increased capacity to degrade environmental chemicals such as atrazine, likely reflecting exposure to wild plants originating from previously agricultural areas.

Compared to other interventions such as B. a plant-only or animal-only diet, the shift caused by wild food consumption was larger. As measured by beta diversity, the shift induced by wild food consumption was greater than that observed with plant or animal dietary interventions alone, although the microbiome did not fully resemble that of traditional or hunter-gatherer populations. Instead, it evolved into a unique composition influenced by available taxa and dietary inputs. The state after resumption of a normal diet was moderate and shared characteristics of both the pre- and wild food phases.

The persistence of some microbial configurations after the intervention suggests partial but permanent reconfiguration. Especially thisBlautia-Dominated network did not fully recede, indicating that certain changes to the gut ecosystem could outlast the diet itself.

However, this was an n = 1 study and the results may not be broadly generalizable. The potential effects of the participant's mood change during the wild food diet and their specific genetic and dietary history remain unexplored.

Conclusions

Lack of Micronutrients, Microbial Bustle: The wild food diet's lack of dairy and eggs correlated with gut microbes increasing the production of phenylalanine, tyrosine and tryptophan—amino acids typically derived from animal products.

In conclusion, this study shows that switching to a diet consisting entirely of wild, non-domesticated foods results in a major restructuring of the human GM. While no new taxa were introduced, the composition and function of existing microbes shifted significantly and increased fiber degradation modes such asBlautiaand slimming dairy products such as:Bifidobacterium.

These microbial changes persisted even after resumption of a normal diet, highlighting the adaptability of the microbiome. Although the lack of taxa of the phylum mayTreponemaThis suggests limitations to fully restoring a traditional microbiome. This experiment highlights the powerful influence of diet alone in transforming gut health, even in a modern setting.

Further studies are needed to examine the metabolic and immunological consequences of these microbiome changes in larger and more diverse populations.

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