Metabolomics of aging requires large-scale longitudinal studies with replication

Aging is a complex biological process with remarkable individual variation and manifests also as changes in systemic metabolism. In a recent paper in PNAS, Chaleckis et al. (1) studied a set of blood metabolites in old and young individuals. The work was thorough in the methodological aspects regarding the mass spectrometry of circulating molecules in plasma, red blood cells, and whole blood. However, we find it alarming that the results and interpretations on the suggested age-related metabolic differences were not properly put into epidemiological context. We therefore draw attention to four key issues: ( i ) metabolic heterogeneity of … [↵][1]1To whom correspondence should be addressed. Email: ville-petteri.makinen{at}sahmri.com. [1]: #xref-corresp-1-1