Pathway
Polyamine Metabolism
Last updated Sat May 30 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
What it is
Polyamines (putrescine, spermidine, spermine) are small organic polycations present in every cell. They bind nucleic acids, modulate translation, support DNA-damage repair, and regulate ion channels. They are made endogenously, obtained from diet, and produced by gut bacteria.
The biosynthetic pathway: ornithine → (ODC) → putrescine → spermidine → spermine. ODC is highly regulated and is a classic target of cancer biology (DFMO inhibits it).
Why it matters in aging
- Tissue polyamine levels decline with age in most studied tissues.
- Spermidine induces autophagy by inhibiting EP300 acetyltransferase, permitting autophagy-gene de-acetylation and activation.
- Lifespan extension in yeast, worms, flies, and mice from dietary spermidine supplementation.
- Human cohort data (Bruneck, others) link higher dietary spermidine intake to lower cardiovascular and all-cause mortality.
Dietary sources
Wheat germ, soy, mature cheese, mushrooms, legumes, amaranth, natto. A polyamine-rich diet delivers 5–25 mg/day; supplementation can add 1–6 mg/day.
Cancer caveat
ODC and polyamine synthesis are upregulated in many cancers (neuroblastoma, melanoma). DFMO — an ODC inhibitor — is approved for neuroblastoma maintenance. The "more polyamines = better" framing of supplementation is context-dependent; growing tumours may not be the place to add fuel.
Related entries
References
- Madeo, F., Eisenberg, T., Pietrocola, F. & Kroemer, G. Spermidine in health and disease. Science 359, eaan2788 (2018).