The name spermidine sounds like something straight out of a laboratory, yet it actually comes from a discovery made over three hundred years ago: a compound from the same family was first described in semen, hence the Latin “sperma” in the name of the whole group. We ferment soy into natto in Zielona Góra, and spermidine is one of the polyamines that accumulate during this process. I have gathered here what is known for certain: where this name came from, what role polyamines play in cells, and what research shows.
⚠️ Are you taking anticoagulant medication (for example acenocoumarol or warfarin)? Natto is one of the richest natural sources of vitamin K, which may affect how these medicines work. Consult your diet and supplements with a doctor. See the important legal and medical information.
In brief
- Spermidine is a natural polyamine, present in every living cell, whose content in natto rises during the fermentation of soy by Bacillus subtilis natto.
- The name comes from semen (Latin sperma), because crystals from this family of compounds were first described there.
- In the literature, natto has been described as one of the richer dietary sources of polyamines.
- In the European Union, spermidine has no authorised health claim (Regulation (EC) 1924/2006), which is why we describe it from the perspective of chemistry, the history of its discovery, and what has been measured in research.
- Most of the data comes from laboratory and animal studies, which do not translate directly into effects in humans.
Where the name spermidine comes from
Spermidine belongs to the polyamine family along with spermine and putrescine. All three were named after the place where their crystals were first observed, namely semen. Already in the 17th century, the Dutch naturalist Antonie van Leeuwenhoek described small crystals in semen, and two centuries later chemists named the compound isolated from them spermine, from the Latin “sperma”. Spermidine, a shorter-chain relative of spermine, received an analogous name, although today it is known that both polyamines are found in virtually all living cells, not only in semen, including in plants, animals and fermented products such as natto. In fermented products the content of polyamines is sometimes higher than in the raw starting material, because during fermentation the bacteria Bacillus subtilis natto break down proteins and create new metabolites. This is a description of composition and process, not a declaration of a health effect.
What role polyamines play in the body
Polyamines, including spermidine, take part in basic cellular processes: DNA replication, protein synthesis and the regulation of cell growth. In the scientific literature their relationship with autophagy, the cellular mechanism for removing worn-out structures, has also been described. The name autophagy comes from Greek: “autos” means self, and “phagein” means to eat, so literally it is “self-eating”, a term coined in the 1960s by the Belgian biochemist Christian de Duve. These are descriptions of mechanisms studied mainly under laboratory conditions and in animal models, not proof of any specific health effect in humans after consuming natto.
What research describes
Spermidine content in natto
In a study by Kobayashi et al. (2016) it was described that the fermentation process involving Bacillus subtilis natto increases the content of polyamines in natto compared with non-fermented soy. Earlier, Okamoto et al. (1997) compared the polyamine content of various foods and fermented products, indicating soy and its products as clearly richer sources of spermidine.
Observations from human studies
In an intervention study by Soda et al. (2021), people who followed a diet rich in polyamines (based on natto) for a longer time had a higher blood spermine concentration than the control group. This shows that polyamines from food can be absorbed, but a single study measuring a biomarker (the level of spermine in the blood) does not prove any specific health effect.
What is not yet known
Most of the data on spermidine comes from laboratory studies (in vitro) and animal models. There is a lack of large, independent clinical studies and of consensus on dosing, which is why results from these models are not directly translated into effects in humans.
How to include natto in the diet
Natto is best eaten without long cooking, as high temperature can affect the content of polyamines and other compounds formed during fermentation. It can be served with rice and vegetables as part of a varied diet.
| Step | Action | Reason |
|---|---|---|
| 1 | Choose natto from natural fermentation | The complete course of fermentation shapes the composition of the product, including the polyamine content |
| 2 | Eat natto a few times a week | Natto can be a regular part of a varied diet |
| 3 | Do not cook natto at high temperature | High temperature can lower the content of compounds formed during fermentation |
| 4 | Combine with vegetables and whole grains | Helps to vary the diet |
| 5 | Observe your body’s reaction | Allows you to adjust the amount to your individual tolerance |
Spermidine in our natto
Spermidine is a natural component of every fermented soy, so you will find it in all our natto. Fresh natto tells the most about it, because it is simply soy right after fermentation, without further processing. We produce it in Zielona Góra from certified organic soy.
See our fresh natto in the shop
Safety and precautions
Natto is a food product safe for most healthy people. Because it is rich in vitamin K2, in certain situations caution is advisable.
This applies in particular to people taking anticoagulant medicines (for example vitamin K antagonists such as warfarin or acenocoumarol), who should consult their doctor about consuming natto. Caution is also recommended for people taking other medicines on a long-term basis, as well as for pregnant women and women who are breastfeeding. Natto contains soy, so it is not intended for people with a soy allergy. A food supplement or any food product does not replace a varied diet and a healthy lifestyle.
Summary
Spermidine is a natural polyamine from the family named after semen, where it was originally observed, although today it is known that it occurs in almost all living cells. Its content in natto rises during the fermentation of soy by Bacillus subtilis natto. The available data comes mainly from laboratory and animal studies, which do not prove a causal relationship with any specific effect in humans. Natto is best treated as part of a varied diet, not as a medicine.
Frequently asked questions
Why is spermidine called that?
Spermidine belongs to the polyamine family along with spermine, named after semen (Latin sperma), where their crystals were first described in the 17th century. Today it is known that polyamines are found in virtually all living cells, not only where they were originally discovered.
What is autophagy, which is mentioned in connection with polyamines?
It is the cellular mechanism for removing worn-out structures, whose name comes from Greek: “autos” (self) and “phagein” (to eat), meaning literally “self-eating”. The connection between polyamines and this process has been described in the literature mainly in laboratory and animal model studies.
Does spermidine from natto differ from the one in supplements?
In natto, polyamines occur in the natural food matrix, alongside other components. This is a different form of intake than an isolated component in a supplement.
Does spermidine have a confirmed effect in the European Union?
No. Spermidine has no authorised health claim in the European Union, which is why a reliable description is limited to its structure, the history of its discovery, and what has been measured in research, rather than its effects. The available data comes mainly from laboratory and animal studies.
Is natto safe for everyone?
For most healthy people, yes. Soy is an allergen, and because of its vitamin K content, people taking anticoagulant medicines and pregnant and breastfeeding women should consult their doctor about consuming natto.
Sources
- Kobayashi K, Shimojo S, Watanabe S. Contribution of a Fermentation Process using Bacillus subtilis (natto) to High Polyamine Contents of Natto. Food Sci Technol Res. 2016.
- Soda K et al. Polyamine-Rich Diet Elevates Blood Spermine Levels and Inhibits Pro-Inflammatory Status: An Interventional Study. Med Sci (Basel). 2021. PubMed
- Okamoto A et al. Polyamine content of ordinary foodstuffs and various fermented foods. Biosci Biotechnol Biochem. 1997. PubMed
- Madeo F et al. Spermidine in health and disease. Science. 2018.
- Regulation (EC) No 1924/2006 and Regulation (EU) No 432/2012; EU Register of Nutrition and Health Claims.
Legal and medical note. This article is educational and does not replace the advice of a doctor or pharmacist. The substances described here have no authorised health claims in the European Union (Regulation (EC) 1924/2006), and a food supplement is not a medicine and does not replace a varied diet. Full information is on the Legal and medical information page.
