Some observational studies have found that COVID-19 affects the imbalance of the intestinal microbiota, and long-term intake of probiotics may help reduce the risk of SARS-CoV-2 infection. Related research suggests that regulating the gut microbiota is helpful in preventing and treating COVID-19[5].
Can Probiotics Regulate Immunity and Reduce the Probability of Respiratory Infections?
Research indicates that probiotics have antiviral activity against common respiratory viruses such as rhinoviruses, influenza viruses, and respiratory syncytial virus (RSV)[2]. Probiotics are believed to reduce the severity of upper respiratory and gastrointestinal infections by regulating immunity and inflammatory factors[3]. Respiratory infections are considered a result of an imbalance in the microbiota of the respiratory and gastrointestinal tracts, so altering the composition of the gut microbiota can protect humans from respiratory infections[4].
Respiratory tract infections (RTIs) are one of the most common infectious diseases caused by viruses or bacteria and can be classified into upper respiratory tract infections (URTIs) and lower respiratory tract infections (LRTIs). Common upper respiratory tract infections include tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, some types of influenza, and the common cold. The lower respiratory tract consists of the trachea, bronchi, bronchioles, and lungs. Viruses are the most common cause of respiratory infections, and COVID-19, caused by the novel coronavirus SARS-CoV-2, is a recent pandemic[1].
What Are Probiotics, and Why Can They Help Boost Immunity?
The microorganisms in the gut can secrete beneficial substances for the human body, such as improving gastrointestinal function and maintaining a healthy intestinal microbiota. These microorganisms are collectively referred to as probiotics. Common bacterial species include those from the Bifidobacterium and Lactobacillus genera[6]. During their metabolism in the human gastrointestinal tract, probiotics produce various substances, such as cell wall fragments, short-chain fatty acids, special functional proteins, organic acids, and more. These substances are believed to help regulate the immune function of the human body[7][8].
Research has shown that different probiotic strains offer varying health benefits[9], and according to studies, supplementing with probiotics is generally safe for most people[10].
Which Probiotics Enhance Immunity?
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Lactobacillus paracasei
Lactobacillus paracasei is believed to regulate the immune system and help alleviate respiratory infection symptoms. Experimental evidence has shown that Lactobacillus paracasei can assist in regulating lung immunity, preventing influenza infections, and being beneficial in reducing the burden of respiratory infections[11].
💡A study on SARS-CoV-2 found that Lactobacillus paracasei significantly induced the expression of genes involved in protective antiviral immunity, enhanced lactoferrin’s antiviral immune activity, and inhibited the proinflammatory response induced by SARS-CoV-2 infection. Furthermore, it was observed that Lactobacillus paracasei has antiviral activity against SARS-CoV-2 and is helpful in preventing SARS-CoV-2 infection[12].
💡In another clinical study, healthy children aged 12 to 48 months were supplemented with fermented milk containing Lactobacillus paracasei, and it was found that the incidence of upper respiratory tract infections and acute gastroenteritis was lower[13]. Other studies have also found that Lactobacillus paracasei can help improve nasal allergies and respiratory inflammation[14]. -
Lactobacillus fermentum
Clinical research has found that adding Lactobacillus fermentum to infant formula significantly reduces the incidence of gastrointestinal infections by 46% and the occurrence of upper respiratory tract infections by 27%, helping infants prevent gastrointestinal and upper respiratory tract infections[15].
💡In a study, subjects vaccinated against influenza were additionally supplemented with Lactobacillus fermentum (10 billion), which resulted in an increase in natural killer cell proportions, the induction of higher helper T cells, an increased humoral immune response, and overall concluded that supplementing with Lactobacillus fermentum enhances the immune response to influenza vaccination[16]. Furthermore, other experimental studies have found that Lactobacillus fermentum can help regulate macrophages, acting as an immunomodulator, inhibiting pneumococcal adhesion to lung cells[17]. -
Lactobacillus rhamnosus
Many studies have suggested that Lactobacillus rhamnosus can improve the frequency and severity of rhinovirus infections[18].
💡Lactobacillus rhamnosus also helps children reduce the infection rate and incidence of respiratory syncytial virus (RSV) infections[19].
💡Due to its ability to regulate immune function, a clinical study involving university students supplemented with Lactobacillus rhamnosus for 12 weeks found that for those who experienced upper respiratory tract infections, the duration of symptoms was significantly reduced by 2 days, and the severity of symptoms was significantly reduced by 34%. Lactobacillus rhamnosus indeed helps improve immunity and reduce the symptoms of upper respiratory tract infections[20].
Which Commercial Brands Contain These Probiotics?
Our team has compiled several commercially available probiotic products that claim to regulate intestinal immunity and support upper respiratory health. We have organized and analyzed the usage of the probiotic strains mentioned in the above studies for respiratory support, which you can refer to:
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Daiken Comfort Probiotic
- Lactobacillus paracasei (Lactobacillus paracasei): AP86: 12 billion, AP88: 12 billion
- Lactobacillus Fermentum (Lactobacillus Fermentum): AP13: 1 billion
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): —
- Notes: Each serving contains a total of 30 billion lactic acid bacteria
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AB LP33 Capsules
- Lactobacillus paracasei (Lactobacillus paracasei): LP33: 500 million
- Lactobacillus Fermentum (Lactobacillus Fermentum): —
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): Not specified
- Notes: Each serving contains a total of 2.5 billion lactic acid bacteria
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GKB New Probiotic
- Lactobacillus paracasei (Lactobacillus paracasei): Not specified
- Lactobacillus Fermentum (Lactobacillus Fermentum): Not specified
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): Not specified
- Notes: Each serving contains a total of 2.5 billion lactic acid bacteria
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Dradvice Probiotics
- Lactobacillus paracasei (Lactobacillus paracasei): Not specified
- Lactobacillus Fermentum (Lactobacillus Fermentum): —
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): Not specified
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Dietician Probiotics
- Lactobacillus paracasei (Lactobacillus paracasei): —
- Lactobacillus Fermentum (Lactobacillus Fermentum): —
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): 750 million
- Notes: Each serving contains a total of 3 billion lactic acid bacteria
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Niang Jia Probiotics
- Lactobacillus paracasei (Lactobacillus paracasei): NTU 101: 600 million
- Lactobacillus Fermentum (Lactobacillus Fermentum): —
- Lactobacillus rhamnosus (Lactobacillus rhamnosus): —
Comparison Table of 6 Commercial Probiotics
| Probiotic Brand | Daiken Comfort Probiotic |
AB LP33 Capsules |
GKB New Probiotic | Dradvice Probiotics | Dietician Probiotics | Niang Jia Probiotics | Mdformula Probiotic Capsules |
| Product Image | |
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|
|
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|
 |
| Lactobacillus paracasei (Lactobacillus paracasei) |
AP86: 12 billion AP88: 12 billion |
LP33: 500 million | Not specified | Not specified | — | NTU 101: 600 million | — |
| Lactobacillus Fermentum (Lactobacillus Fermentum) |
AP13: 10 billion | – | Not specified | – | – | – | – |
| Lactobacillus rhamnosus (Lactobacillus rhamnosus) |
– | Not specified | Not specified | Not specified | 750 million | – | Not specified |
| Notes | Each serving contains a total of 30 billion lactic acid bacteria | Each serving contains a total of 2.5 billion lactic acid bacteria | Each serving contains a total of 15 billion lactic acid bacteria | Each serving contains a total of 3 billion lactic acid bacteria |
When choosing probiotic products for upper respiratory tract maintenance during times of epidemic alert, it is important to select clinically suitable strains.
Two Key Principles for Selecting Probiotics to Prevent Respiratory Tract Infections
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Utilize Multiple Strains Targeting Respiratory Research
Most studies currently employ single or dual strains, with only a few using multiple probiotic strains for research. Research indicates that the supplementation of multiple strains has a greater effect than a single strain[21]. Therefore, when selecting probiotic products aimed at upper respiratory tract health, choosing a product containing multiple strains targeted for respiratory research may achieve better health benefits.
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Clearly Indicate the Dosage Used
In general, the intake dosage used in studies ranges from at least 100 billion CFU per day or higher to 300 billion CFU to have clinical significance[22].
Four Brands of Probiotics Containing Respiratory Immune Strains Available in the Market
The above products contain the three strains mentioned. However, Grape King, unfortunately, does not indicate the dosage. On the other hand, Uni-LP33 Capsules, Daiyen Comfort, and HealthForce Allergy Support Probiotics contain two strains targeting respiratory immunity, with Daiyen Comfort Probiotic Capsules providing complete dosage information. The information provided above is for your reference when making a choice.
Supplementing probiotics is beneficial for improving allergy conditions, preventing upper respiratory tract infections, preventing gastrointestinal infections, and recent research suggests that probiotics can help prevent SARS-CoV-2 infection and recovery. Although there is no consensus in clinical practice regarding the optimal dosage, duration, or specific probiotic strains to use, the benefits of probiotics to human health are undeniable. The information provided above serves as a reference for individuals in Taiwan when selecting probiotics.
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Comparison of 6 Recommended Brands of Probiotic Products on the Market in 2023
