Seasonal cycling in the gut microbiome of the Hadza hunter-gatherers of Tanzania.
Level 3 - non-randomized controlled study
Longitudinal observational cohort study with comparative population data, graded by design analogy.
PubMed 28839072 · doi:10.1126/science.aan4834
What was done
Microbiome profiling was performed on 350 stool samples collected longitudinally for more than a year from Hadza hunter-gatherers in Tanzania. The data were evaluated for temporal variations across seasons and compared against microbiome data sets from 18 populations across 16 countries with varying lifestyles and degrees of modernization.
What was found
The abstract reports no numerical values, effect sizes, or specific statistical test statistics. It reports that the Hadza gut microbiome undergoes annual cyclic reconfiguration, with certain taxa becoming undetectable in some seasons and reappearing in subsequent seasons. Furthermore, the taxa exhibiting the greatest seasonal volatility in the Hadza correspond to the lineages that differentiate traditional and industrialized populations, showing decreased prevalence and abundance in modernized cohorts.
Why it matters
This study demonstrates that ancestral gut microbial communities are dynamic and seasonally adaptable, suggesting that industrialization is associated with the loss of specific environmentally responsive microbial lineages.
Limits
The abstract does not state the number of unique human participants (only 350 stool samples) and provides no numerical data, effect sizes, or specific taxonomic identities. As an observational study in a single hunter-gatherer population, it cannot establish causal mechanisms driving the loss of these taxa or determine the health consequences of their absence in modernized populations.
Cited by
- supports The gut microbiome of the Hadza hunter-gatherers undergoes cyclical, seasonal shifts in composition.