Conclusions
food-borne
The volatile fraction of human biological
tissues and fluids was,
until recently, little researched in human nutrition studies. Recent
progress in volatile extraction and identification has allowed expansion
of current knowledge of postprandial metabolomes on its volatile component.
Many of the postprandial metabolites reported in serum in this study
were also detected in the dairy products, suggesting that, due to
their small size and fast absorption, these molecules are not, or
only partly, transformed by the human organism. On the other hand,
this study further strengthened the use of 3,5-dimethyl-octan-2-one
as a candidate marker of dairy product intake although this molecule
is evidently not present in dairy products but, rather, metabolized
from an unknown dairy fat precursor by the human organism. Independent
of the fate of food-borne metabolites, untargeted volatilome analysis
is emerging as an interesting analytical strategy to detect biomarkers
of food intake.Surprisingly, analysis of the serum volatilome
of the study samples
provided limited evidence for metabolites whose postprandial response
is indicative of the fermentative status of the ingested dairy product.
Indeed, Fuchsmann The most remarkable observation
resulting from the analysis of
the volatilome is the age dependency of the metabolites reacting to
the nutrition interventions during the postprandial phase as well
as during the 3 week restriction period. Independent of the involved
mechanisms, our results demonstrate that lower fasting values of metabolites
that are acutely reactive to food intake are generally associated
with higher postprandial response in older adults.