Several studies have shown LG2055, Lactobacillus paragasseri SBT2055, to enhance immunity. This study examined LG2055 and its effect on healthy adults’ subjective symptoms of physical condition.

All generations worldwide are familiar with the common cold, characterized by local symptoms mainly affecting the upper respiratory tract (coughing, runny nose, blocked nose, sore throat, and sneezing) and systemic symptoms (such as fever, chill, and fatigue).

Infections of the upper respiratory tract by microorganisms, primarily viruses, cause the common cold. However, because many viruses can cause the common cold, identifying the responsible virus is not always possible.

It is, therefore, advisable to treat common colds with symptomatic treatment and adequate rest. Additionally, common colds cause several social problems, including higher medical expenditures, decreased productivity, and economic losses.

Recently, various LAB strains have been studied for their availability and functionality. The most common function is improving the intestinal environment; other LAB functions have been reported, including immunomodulation, weight loss, and anti-inflammatory effects.

Functional LABs, such as probiotics, are microorganisms that provide health benefits when administered adequately. Probiotics are not the only practical LABs identified as providing health benefits in recent years, as have non-viable bacteria, bacterial components, extracts, and metabolites derived from bacteria.

This leads to postbiotics, defined as the “preparation of inanimate microorganism and their components that benefit the host.”.

Methodology & Results

The researchers recruited Japanese individuals aged 20–64 to participate in this randomized, double-blind, placebo-controlled, parallel-group comparative study. An independent controller randomly assigned 200 participants to two groups (LG2055 and placebo groups; 100 participants each).

Drinkable yoghurt that contained LG2055 or was lacking LG2055 (placebo) was used as a test sample, and participants ingested one bottle once a day for 12 weeks. A daily physical health questionnaire (about common cold symptoms) was used as a primary outcome, and secondary outcomes included immunological and oxidative stress markers.

The total number of participants completing the scheduled intake of testing samples was 198, and five participants were excluded from the final analysis. Therefore, 193 participants (LG2055 group, n = 97; placebo group, n = 96) in the Per-Protocol Set were included in the efficacy analysis.

According to the cumulative days of each symptom, LG2055 participants had a significantly higher ratio of “without symptoms” in runny noses, plugged noses, sneezing, sore throats, hoarseness, cough, headaches, feeling tired, and fevers than placebo participants, indicating that LG2055 patients had lower rates of common cold symptoms.

Furthermore, salivary secretory IgA levels tended to be higher in LG2055, and serum derivatives of reactive oxygen metabolites tended to be lower.

Thus, LG2055 intake decreased common cold symptoms and improved immune parameters in healthy adults, suggesting that LG2055 may contribute to physical health maintenance.

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