🔎 Today’s Daily Sift: Longevity Longevity is becoming less universal. Three new studies point toward the same idea. There may not be one biological age. There may be several. A Nature Aging study published August 25 identified a gut bacterium called Bifidobacterium pseudocatenulatum that declined with age across multiple human cohorts. When researchers gave it to aged mice, the animals showed less inflammation across several organs, better cognitive and motor performance, and improved healthspan. A metabolite produced by the bacterium, called 5 AVAB, also declined with human aging and reproduced some of those benefits experimentally. This is not evidence that a probiotic extends human life. It is evidence that the microbiome may actively participate in aging biology. Another Nature Aging study analyzed 172 clinical measures from more than 100,000 people. Men and women followed different aging trajectories during midlife before converging later in life. Metabolic factors ...