Spermidine: the cellular ally of longevity

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Spermidine is a small natural molecule, but its effects on our cells and our health are anything but modest. Found in all living organisms, it plays a key role in maintaining cellular vitality, protecting organs and supporting healthy ageing. In this article, we dive into the heart of this fascinating polyamine.

What is spermidine?

Spermidine belongs to the polyamine family, compounds that are essential to life. Our body produces it naturally from arginine, an amino acid, but it can also be supplied through the diet. It is found in particular in:

• Aged cheeses
• Fermented soy, such as natto
• Mushrooms and green vegetables
• Whole grains and certain seeds

With age, endogenous spermidine production declines, which may contribute to the loss of cellular vitality observed in older adults.

The superpowers of spermidine

1. Activation of autophagy

Autophagy is the cell’s natural cleaning process. It removes misfolded proteins and damaged organelles, thereby limiting oxidative stress and inflammation. Spermidine is a powerful inducer of autophagy, which gives it a protective role against cellular ageing and certain neurodegenerative diseases such as Alzheimer’s or Parkinson’s.

2. Protection of the heart and blood vessels

Animal and epidemiological studies suggest that spermidine helps preserve cardiovascular health. It helps maintain the flexibility of blood vessels, reduces oxidative stress and protects the heart from age-related remodelling.

3. DNA stabilisation and cellular regulation

Spermidine binds to DNA and RNA, stabilising their structure and taking part in the regulation of protein synthesis. This function is crucial for proper cellular function and for preventing the dysfunctions associated with ageing.

4. Effects on longevity

In animals, dietary intake of spermidine or high endogenous levels are associated with:

• Increased longevity
• Preservation of memory and cognitive function
• A reduced cardiovascular risk

These effects appear to be linked to the activation of protective metabolic pathways and to the reduction of oxidative stress.

Supplements or diet?

Spermidine-containing foods may be part of a varied diet, but no clinical “spermidine deficiency” justifying supplementation has been established. SmartAge found no significant cognitive or biomarker benefit with 0.9 mg/day for 12 months. Supplements therefore cannot be recommended as a longevity strategy. Evidence level: clinical benefit not demonstrated.

In practice: boosting your spermidine every day

• Include aged cheeses, fermented soy, mushrooms and whole grains in your meals
• Favour a varied diet rich in polyamines
• Maintain regular physical activity, as it enhances autophagy
• Limit dietary excess and oxidative stress, which reduce the effectiveness of polyamines

Conclusion

Spermidine participates in autophagy and several cellular pathways, but a plausible mechanism does not establish a longevity benefit in humans. SmartAge was negative for memory and biomarkers, while POLYCARe remains a protocol. Conclusion: emerging mechanistic interest; clinical efficacy not demonstrated.