Actinobacteria
Actinobacteria is a phylum that, in the gut, is best known for containing Bifidobacterium, a group widely studied as a beneficial microbe. Its value here is the relative share of your sample made up by this group.
Although usually a smaller slice of the adult gut than Firmicutes or Bacteroidetes, Actinobacteria draws attention because Bifidobacterium is prominent in infancy and features in many probiotic and fermented-food discussions. Its share can reflect diet, life stage, and fiber intake.
A higher Actinobacteria share often reflects a larger relative presence of Bifidobacterium, which is generally framed positively in the research. As a relative snapshot of one sample, a higher share is a supportive signal rather than a diagnosis.
A lower Actinobacteria share means this group forms a smaller part of your sample, which some people see with lower intake of fiber and fermented foods, though it does not diagnose anything by itself.
Common guidance points toward fibers and foods that feed Bifidobacterium, such as varied plants and some fermented foods, rather than a fixed target percentage. This is an evolving field, so read the trend over time and interpret with a clinician.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.