Taiyo GmbH

Supporting the immune system

with dietary fibers and polyphenols:

good news for consumers

and the food industry


Interview with Dr Stefan Siebrecht, Managing Director, Taiyo GmbH, Germany


Taiyo, a pioneer in the research and production of functional ingredients for the food, beverage, medical food and pharmaceutical industries, works constantly to develop innovative, science-backed solutions. The company is currently working on an antiviral mouth spray concept based on a green tea extract that can even inactivate coronaviruses. We talk to the Managing Director of Taiyo GmbH about healthy habits, the link between the gut and the immune system … and findings from science.

You have developed a concept for an antiviral mouth spray. How did you come up with this approach and what is the link to the immune system?

Stefan Siebrecht: In general, one must distinguish between three phases of the immune system response: pre-, acute and post-attack. Even in healthy people, the immune system needs triggers to prepare and form certain antibodies. Vaccines, sport and heat/cold stimuli are excellent examples. During an acute viral attack, for example, the immune system needs more nutrients than usual to generate enough energy to effect a defense. Vitamins, minerals and polyphenols from fruits and tea are good sources, as are antiviral and antibacterial plant extracts. Polyphenols, in particular, which can be said to act like natural antibodies, suppress the adhesion and penetration of viruses and bacteria, and can therefore protect against infections. After a successfully repelled attack, it’s important to bring the immune system back into balance so that it doesn’t damage the body’s own healthy cells. Our polyphenol-based mouth spray is designed for the acute phase, when it’s important to prevent something serious from happening.

How did you come up with polyphenols and why do they, of all things, prove to be a promising approach?

Because of our roots. Taiyo, as a Japanese company with a subsidiary in China, has long been working with tea and tea ingredients. We exclusively source green tea varieties from long-standing contract partners and monitor the conditions ourselves. Moreover, we also process them in our own factories, according to FDA guideline 40CFR180, to ensure the highest possible quality. Last autumn, several studies were published that dealt with the coronavirus-inactivating effect of tea ingredients. Laboratory experiments at Japan’s Nara Medical University demonstrated that tea extracts could be used to detoxify the virus in humans.[1] A German study showed that green tea infusions and juices such as elderberry or pomegranate were also able to reduce the viral infectivity of influenza and SARS-CoV-2 virus titers in vitro.[2] Based on these findings, our own scientists at Taiyo Kagaku performed an in vitro study to verify their results by using a highly potent green tea extract with a known and defined quantity of catechins. For the study, human fetal lung fibroblasts were mixed with active coronaviruses and green tea before the solution was cultured at 37°C for 96 hours to evaluate virus-derived cytotoxicity. The effect most likely derives from presence of catechins and polyphenols, although further studies are needed to substantiate the results.

This means that the polyphenols from tea can fight the virus – how exactly does that work?

This is achieved through different mechanisms of action, such as by interacting with and inactivating the viruses: catechins can react with viral spike proteins and/or with cellular binding sites by processes such as anti-adhesion and anti-invasion (Fig. 1).[3] In addition, catechins can enhance viral clearance from the body through agglutination (clumping) and have also been shown to inhibit the enzymes necessary for virus replication. The ability to destroy the virus directly has also been scientifically proven.[4]

Figure 1: Antibodies bind to and block the spike proteins of viruses. As a result, viruses cannot bind to the receptors of human cells and/or penetrate them


What effect would eliminate the viral load in the current pandemic?

A step forward in the fight against the pandemic would be to achieve a situation whereby fewer or no live virus particles were excreted when speaking or coughing. As the viral load in the upper respiratory tract is one of the decisive factors in the spread of SARS-CoV-2, it seemed obvious to focus on the mucous membranes as a point of entry. After the transmission of SARS-CoV-2 via respiratory aerosols or droplets from infected individuals, the virus must enter human cells by passing through their outer membranes to start multiplying and causing an infection.[5] The primary aim of the rolled-out vaccines is to produce antibodies that block the spike proteins of the virus, which are used to attach to the cell and invade.

As mentioned at the beginning, Taiyo has developed a concept for an oral mouth spray. How did you come up with this approach and how is it used?

Numerous studies have shown that gargling with green tea helps people to protect themselves against the influenza virus, which also enters via the upper respiratory tract. More recent studies also show that gargling kills coronaviruses. So, an oral approach was the obvious choice. Most mouthwashes or rinses, however, are not meant to be taken on-the-go. So, Taiyo created a concept for a convenient, 100% natural and safe oral care mouth spray that can be used in situations that might pose a risk of infection, such as at the workplace or on public transport. However, it is a food product; different kinds of green tea extracts were combined to ensure safe consumption and offer a convincingly pleasant taste. Teavigo®, for example, is rich in EGCG and Sunphenon®, which is a highly fermented green tea extract that’s high in EGC, is particularly effective against many different viruses and bacteria (Fig. 2). This spray, in addition to the distance and hygiene rules, wearing a mask, etc., may constitute another layer of defense and could inactivate any coronavirus particles that might pass through a mask and/or are already in the mouth and body.

Apart from the new concept, strengthening the immune system to ward off diseases also plays a strong role in other products from your portfolio.

Figure 2: Taiyo’s green tea extracts are high in EGCG or EGC. Copyright: Taiyo


Which product stands out in particular?

Modern eating habits and taste preferences mean that the average person’s dietary fiber consumption levels are far below what is recommended by nutritionists. With Sunfiber®, however, Taiyo offers a simple way to close that gap. Derived from the Indian Guar Bean, Cyamopsis tetra-gonolobus, this water-soluble ingredient has all the nutritional benefits of a dietary fiber and also acts as a prebiotic within the gastrointestinal tract.

How can a dietary fiber strengthen the immune system, what is the connection in this respect?

Put simply, a chronic lack of dietary fiber leads to a decrease in the protective intestinal mucus layer. Our immune system is a very complex system of barriers, cells and chemicals that all work together to protect our health. It is said that 70–80% of our immune system is located in the gut (Fig. 3). Our intestines are an important barrier to the outside world. Along with the mucous membranes of the lungs, the intestinal mucous membranes are some of the thinnest parts of the body, through which germs and toxic substances can penetrate most easily. As such, the intestinal barrier represents an important component of our immune system.

Figure 3: Two thirds of the human immune system is located in the gut. Copyright: Shutterstock


How does dietary fiber help to strengthen this barrier?

Both the intestinal mucosa and the intestinal bacteria carry out important functions – and are in close contact with each other. The composition of the intestinal bacteria depends on a fiber-rich diet. Our intestinal health is protected in three ways by the intestinal bacteria: by the number of good bacteria such as Bifido and Lactobacillus, for example, by the balance between good and bad bacteria and by the diversity of species. During digestion, the good intestinal bacteria form short-chain fatty acids from dietary fiber, which serve our body as nutrients, protect us from cancer, send satiety signals to the brain and increase the acidity in the intestine (which harmful bacteria don’t like). A low-fiber, high-fat, high-carbohydrate diet leads to an increase in bad bacteria, which then break down the intestinal mucus, reducing the amount of protection. The next line of defense in the intestine is antibodies; that is, immune proteins (immunoglobulins) that adhere to the surface — the spike proteins — of bacteria or viruses. The penultimate barrier is formed by the tight junctions that make paracellular spaces impermeable. The production of tight junction proteins is supported by the consumption of water-soluble dietary fibers. The last bastion is cellular immune defense (Fig. 4).

Figure 4: The gut and its five lines of defense. Copyright: Taiyo


According to this, the intake of dietary fiber can help the different defense lines of the gut to stay healthy. Let’s return to our initial topic, the coronavirus. To what extent does nutrition play a role here?

A large proportion of COVID-19 patients also experience gastrointestinal problems. More than 50% of all sufferers have digestive problems and about 47% have both digestive and lung complaints.[6] As early as 2003, in the course of the first SARS epidemic, it was discovered that the SARS virus uses a special endogenous enzyme on the surface of our cells as a gateway, namely angiotensin-converting enzyme-2 (ACE-2).[7] In 2004, ACE-2 protein was found on the surface of lung cells and the cells of the intestinal mucosa, as well as in the oral and nasal mucosa, lung, stomach, small intestine, colon, skin, lymph nodes, thymus, bone marrow, spleen, liver, kidney and brain.[8] It can therefore be said that this ACE-2 enzyme is present in practically all organs, but its function remains largely unknown. The SARS-COV-2 virus is able to use this ACE-2 enzyme as a gateway in all these organs to attack the local cells and ultimately cause multiple organ failure.

According to one rat-based study, microbial dysbiosis in our gut induces the production of the SARS-CoV-2 receptor ACE-2 and thus increases the infectivity of the gut, meaning the virus can replicate more easily and better in such an environment.[9]

Does it mean that with the right gut bacteria, disease triggers find less of a target?

Exactly! To summarize, dietary fiber has eight effects: many dietary fibers have a prebiotic effect and thus feed the good bacteria, they help to form more digestive fatty acids (short-chain fatty acids), which inhibit and suppress the growth of putrefactive bacteria. They support biodiversity, mucosal formation and the production of IGA antibodies. They also reduce the aforementioned ACE-2 and support the production of tight junction proteins, which increase the tightness of the intestinal wall and facilitate wound healing.

Let´s get back to Taiyo´s dietary fiber Sunfiber©. We have already reported on this product in previous issues, for example in connection with influencing insulin secretion. What should one know about it?

The product also offers a number of clinically substantiated health benefits for the entire body. Sunfiber®, which is a 100% natural bean fiber, slows down and reduces the absorption of fat, cholesterol and sugar, and has even been shown to lower the glycemic index, contributing to stabilized blood glucose levels. In fact, Sunfiber® can reduce post-meal blood glucose levels by 20%, and has been granted a health claim by the Canadian health authorities. When consumed with a meal, for example, it improves the absorption of minerals such as calcium and magnesium. In addition, unlike some other dietary fiber sources, it is compatible with a low FODMAP diet: its fermentation rate is very slow, which means that it does not result in painful gas, cramping or discomfort.

Finally: What advice would you give to ingredient manufacturers?

Natural, plant-based nutritional ingredients, such as those found in the two products under discussion — green tea extracts and dietary fiber — are a more attractive market segment than ever before. Next-generation ingredients can help food, beverage and supplement manufacturers to give consumers what they are looking for: products that enable them to enhance their well-being and do something to maintain health and prevent a range of diseases. From the industry’s point of view, it’s important to keep an eye out when purchasing raw materials and products; what’s interesting for food manufacturers is always a lucrative market for counterfeiters as well.

Unfortunately, this is not going to change anytime soon, so we need to pull out all the stops to make the supply chains as safe as possible.


Dietary fiber and the immune system

  • Our intestines host billions of bacteria, viruses and fungi
  • The intestine contains around 1000 different strains of bacteria
  • Some bacteria are harmful to our body
  • A healthy balance of bacteria is important for our intestinal health
  • Dysbiosis (imbalance in the intestinal flora) has a negative impact on human health
  • The human immune system works together with the intestinal bacteria
  • Dietary fiber can improve the human immune system
  • Water-soluble fiber improves mucosal immunity
  • Water-soluble fiber increases the intestinal barrier and the production of tight-junction proteins that seal the intestinal wall
  • Water-soluble fiber increases the production of immuno-globulins and antibodies

S. Siebrecht, Natürlich Immun – die körpereigene Krankheitsabwehr stärken. Mit Vitaminen, Mineralien und Heilkräutern das Immunsystem aufbauen (Via Nova Verlag, Petersberg, Germany 2021).



1 Y. Hisakazu, “About the Inactivating Effect of the New Coronavirus by Tea,” press release from Nara Medical University (25 November 2020).
2 B. Frank, et al., “Antiviral Activity of Plant Juices and Green Tea Against SARS-CoV-2 and Influenza Virus in Vitro,” (2020): doi.org/10.1101/ 2020.10.30.360545.
3 K. Kawai, et al., “Epigallocatechin Gallate, the Main Component of Tea Polyphenol, Binds to CD4 and Interferes with Gp120 Binding,” Journal of Allergy and
Clinical Immunology 112(5), 951–957 (2003): doi:10.1016/S0091-6749(03)02007-4.
4 K. Yamaguchi, et al., “Inhibitory Effects of (−)-Epigallocatechin Gallate on the Life Cycle of Human Immunodeficiency Virus Type 1 (HIV-1),” Antiviral Research 53(1), 19–34 (2002): doi:10.1016/S0166-3542(01)00189-9.
5 P. Anfinrud, et al., “Visualizing Speech-Generated Oral Fluid Droplets with Laser Light Scattering,” The New England Journal of Medicine 382(21), 2061–2063 (2020): doi:10.1056/NEJMc2007800.
6 L. Pan, et al., “Clinical Characteristics of COVID-19 Patients with Digestive Symptoms in Hubei, China: A Descriptive, Cross-Sectional, Multicenter Study,” The American Journal of Gastroenterology 115(5), 766–773 (2020): doi:10.14309/ajg.0000000000000620.
7 W. Li, et al., “Angiotensin-Converting Enzyme 2 is a Functional Receptor for the SARS Coronavirus,” Nature 426(6965), 450–454 (2003): doi:10.1038/ nature02145.
8 I. Hamming, et al., “Tissue Distribution of ACE2 Protein, the Functional Receptor for SARS Coronavirus. A First Step in Understanding SARS Pathogenesis,” The Journal of Pathology 203(2), 631–637 (2004): doi:10.1002/path.1570.
9 T. Yang, et al., “Gnotobiotic Rats Reveal That Gut Microbiota Regulates Colonic MRNA of ACE2, the Receptor for SARS-CoV-2 Infectivity,” Hypertension 76(1), e1-e3 (2020): doi:10.1161/HYPERTENSIONAHA.120.15360.