Official websites use. Share sensitive information only on official, secure websites. As spermidine levels decline with age, spermidine supplementation is suggested to prevent or delay age-related diseases. However, valid pharmacokinetic data regarding spermidine remains lacking. Therefore, for the first time, the present study investigated the pharmacokinetics of oral spermidine supplementation. The plasma metabolome was investigated using nuclear magnetic resonance NMR metabolomics.
No effect on salivary polyamine concentrations was observed. Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine. Spermidine is a biogenic polyamine that plays a crucial role in cellular homeostasis, cell growth, proliferation, and autophagy [ 1 , 2 , 3 ]. Research has found a relevant role for biogenic polyamines in both health and disease [ 4 , 5 ]. The physiological spermidine pool is fed by cellular de novo synthesis, intestinal microbiota biosynthesis with subsequent absorption, and dietary sources [ 6 ].
In mammalian cells, spermidine is generated from its precursor putrescine or through the degradation of spermine [ 7 ], and different mechanisms of transmembrane transport contribute to the regulation of intracellular spermidine concentrations [ 8 ].
Polyamines including spermidine in the gastrointestinal lumen originate from food, intestinal microbiota, pancreatic-biliary secretions, and degraded intestinal cells [ 9 , 10 ], and dietary polyamines are proposed to be the main source of luminal polyamines [ 8 ]. The average daily nutritional intake of spermidine in European countries varies from approximately 10 to 15 mg [ 11 ]. The dietary sources of individual spermidine intake vary widely due to individual food preferences and regional dietary habits [ 13 , 14 ].
The main dietary sources of spermidine are potatoes 6. To date, little is known about the mechanisms of intestinal absorption, presystemic metabolism, and the kinetics of polyamine transport systems in humans [ 8 ].
