Tier 3 — preclinical

Long-term oral polyamine intake increases blood polyamine concentrations

Kuniyasu Soda, Yoshihiko Kano, Masako Sakuragi, Koichi Takao, Alan Lefor, Fumio Konishi

Journal of Nutritional Science and Vitaminology (Tokyo) 2009 55(4):361-366

Bibliography

PubMed: PMID 19763038
DOI: 10.3177/jnsv.55.361

Study snapshot

Design	Controlled dietary intervention with parallel mouse feeding experiment
Model	Healthy male volunteers and mice
Sample	17 humans (10 intervention, 7 control)
Intervention	50-100 g/day polyamine-rich natto versus avoidance of polyamine-rich foods
Duration	2 months in humans
Endpoints	Blood spermine; Blood spermidine; Polyamine concentrations

What the study showed, in plain terms

An early human dietary study found that eating polyamine-rich natto for two months increased blood spermine, while blood spermidine itself did not show the same simple rise. This supports the idea that oral polyamine exposure can alter systemic polyamine metabolism.

Key findings

The study is relevant to bioavailability because dietary polyamines changed circulating polyamine patterns, but it does not isolate spermidine and cannot be used to infer clinical anti-aging benefits.

What this study can and cannot tell us

Very small, non-randomized human sample, food-based mixed-polyamine intervention and short duration.

Editorial review

Reviewed by the Biohack Blueprint research team

Khaled Mahmoud