PQQ sounds like a name straight from a chemistry textbook, and it really is a small molecule that scientists first found in bacteria before discovering it was also in our food. In Zielona Góra we make natto from fermented soy, and PQQ is one of the compounds that fermentation leaves in the finished product. I have gathered here what is known about it for certain: where its name came from, how it was discovered and where it occurs.
⚠️ 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 short
- PQQ (pyrroloquinoline quinone) is a small molecule with redox properties, meaning it is capable of taking part in electron transfer.
- It was first described in bacteria, where it acts as a cofactor of certain enzymes, before it was also found in food.
- It occurs naturally in many foods, and natto, according to measurements described in the literature, is among the richer sources.
- In the European Union, PQQ as an isolated, extracted ingredient has the status of novel food, and as a compound it has no authorised health claim (Regulation (EC) 1924/2006).
What PQQ is and where its name comes from
PQQ stands for pyrroloquinoline quinone. The name describes the structure of the molecule: it combines a pyrrole ring, a quinoline system and a quinone group. Quinones are a well-known class of compounds in chemistry that take part in redox reactions, meaning electron transfer. Vitamin K, which in our natto occurs in the form K2 (MK-7), belongs to the same family. PQQ was first described in bacteria in the 1960s and 1970s, as a prosthetic group, meaning a fixed, non-protein element of certain enzymes called dehydrogenases. Only later did it turn out that the same compound also occurs in food.
Where PQQ occurs
PQQ is widespread in food, though usually in small amounts. Measurements described in the literature indicate that natto is among the products with a relatively high content of this compound compared with other foods studied. The table below gives the values described in one of the studies.
PQQ content in selected products
| Food product | Average PQQ content (ng/g) | Data source |
|---|---|---|
| Natto | up to about 61 | Kumazawa et al., 1995 |
| Green pepper | about 28 | Kumazawa et al., 1995 |
| Kiwi | about 21 | Kumazawa et al., 1995 |
| Whole milk | < 10 | Kumazawa et al., 1995 |
In the cited study (Kumazawa et al., 1995) the content of free PQQ in all the products studied was in the range of 3.7 to 61 ng/g, and natto was among the richest sources. The values relate to a specific study and may differ depending on the sample and the measurement method.
What research shows
Research on PQQ has been conducted mainly under laboratory conditions (in vitro) and in animal models, describing its redox properties and its role as an enzymatic cofactor in bacteria. In 2003 a paper appeared in the journal Nature suggesting that PQQ might be an important nutritional factor for mammals, which is why it is sometimes called a vitamin-like compound. It has no formal status as a vitamin, however, and results obtained in a test tube and in animals do not automatically translate into effects in humans after oral intake. Clinical studies in humans are few and methodologically varied, which is why we do not attribute any specific effect to PQQ.
PQQ in our natto
Natto is made when we ferment cooked soy with the bacterium Bacillus subtilis natto. In this process various compounds appear in the product: PQQ, vitamin K2 in the MK-7 form, the enzyme nattokinase, and live fermentation bacteria cultures. This is a description of the composition, not a declaration of a health effect. Of the ingredients listed, only vitamin K may be spoken of in terms of a specific role (it contributes to normal blood clotting and to the maintenance of normal bones); PQQ and nattokinase have no such basis. You will find the most PQQ in our fresh natto, as it is simply soy right after fermentation, without any 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 that is safe for most healthy people. Due to its vitamin K content, people taking anticoagulant medicines from the vitamin K antagonist group (for example warfarin or acenocoumarol) should consult a doctor about consuming natto. Natto contains soy, so it is not intended for people with a soy allergy. Neither a dietary supplement nor any food product replaces a varied diet and a healthy lifestyle.
Summary
PQQ is a small molecule with redox properties, first known as a cofactor of bacterial enzymes and later also described in food, including natto. Its name reflects the chemical structure of the compound, as is the case with many other organic chemistry compounds. In the European Union, PQQ as an isolated ingredient is subject to novel food regulations, and research into its effects in humans is still at an early stage. Natto is best treated as part of a varied diet, not as a medicine.
Frequently asked questions
What is PQQ?
It is a small molecule with redox properties, first described in bacteria as a cofactor of certain enzymes. It was later also found in food, including natto.
Is PQQ a vitamin?
It has no formal status as a vitamin. It is sometimes called a vitamin-like compound because it was suggested that it might be important in the diet of mammals, but this is a descriptive term, not a regulatory status.
What status does PQQ have in the European Union?
PQQ as an isolated, extracted ingredient has in the EU the status of novel food, so its use in this form is subject to separate regulations. This is a different matter from the presence of PQQ as a natural element of fermented food such as natto, where it has always been part of the composition and is not an added raw material. As a compound, PQQ also has no authorised health claim, which is why we do not attribute any specific effect to it.
Is natto a good source of PQQ?
Measurements described in the literature indicate that natto is among the products with a relatively high content of PQQ compared with other foods studied.
Does PQQ have a confirmed effect in humans?
Clinical studies in humans are few and methodologically varied. Results obtained in a test tube and in animal models do not translate directly to humans.
Does consuming natto require caution?
Due to its vitamin K content, people taking anticoagulant medicines should consult a doctor about consuming it. Natto also contains soy, so it is not suitable for people with a soy allergy.
Sources
- Kumazawa T. et al. Levels of pyrroloquinoline quinone in various foods. Biochem J. 1995. PubMed
- Kasahara T., Kato T. A new redox-cofactor vitamin for mammals. Nature. 2003. Nature
- Jonscher K.R. et al. Pyrroloquinoline-Quinone Is More Than an Antioxidant. Biomolecules. 2021. MDPI
- Regulation (EC) No 1924/2006 and EU Register of Nutrition and Health Claims (European Commission).
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.
