The beverage studied contains Lactococcus lactis subsp. lactis JCM 5805, also known as LC-Plasma – a functional ingredient by Kirin.
Existing studies have shown that LC-Plasma, which was first discovered in 2010, functions as the ‘commander-in-chief’ of the immune system by stimulating the plasmacytoid dendritic cells (pDC).
This particular RCT took place in Vietnam, where Kirin has been selling iMUSE – a range of functional foods and drinks which contain LC-Plasma.
A bottle of iMUSE drink is currently sold in Vietnam’s supermarkets, convenience stores, and small-scale shops at US$0.4 to US$0.5 each.
However, the LC-Plasma containing product used in this study has not yet been commercialised.
As its first overseas study involving children, the RCT aims to find out 1) the efficacy of LC-plasma in reducing absenteeism due to upper respiratory disease (URID) and gastrointestinal disease (GID) and 2) the potency of LC-plasma on the two conditions and general well-being.
The symptoms of URID include fever, cough, runny nose, while that of GID include constipation, diarrhoea, and abdominal pain.
About 1,000 students between primary one and three took part in the RCT, where they were randomised to take either the placebo or the intervention.
The intervention is a 280ml drink containing 50mg of heat-killed LC-plasma – equivalent to 1 trillion CFU.
The drink also contains skim milk powder, sugar, sweetener, and citric acid.
Findings of the study was published in Nutrients.
The cumulative number of days absent from school due to cold and flu was significantly reduced in the group consuming LC-plasma.
A total of 956 participants completed this study.
By week four of the trial, the cumulative days absent from school due to URID or GID was 38 in the intervention group, significantly lower than the 70 days reported in the control group.
The cumulative days absent from school due to URID alone was 33 in the intervention group and 62 in the control group.
From week five onwards, however, both groups did not differ significantly in the number of cumulative days absent from school.
For the intervention group, it was 29 days of cumulative absence and 33 for the placebo group – not a difference of statistical significance.
On the other hand, there was also a significant difference between the two groups in terms of the number of cumulative fever positive days.
By week four of the study, the number of cumulative days with fever was 108 in the control group but 60 in the intervention group.
Based on the findings, the researchers concluded that the supplementation of LC-plasma could reduce school absenteeism caused by infectious diseases.
“LC-Plasma is reported to have preventive effects on URID, including the common cold and influenza, via enhancement of an IFN-α-mediated response.
“LC-Plasma intake was predicted to improve mild URID symptoms; however, further detailed studies, including objective clinical data using more symptomatic subjects, should be conducted to evaluate the effects of LC-Plasma intake in high risk areas of infectious disease,” the researchers said.
Impact of Infectious Disease after Lactococcus lactis Strain Plasma Intake in Vietnamese Schoolchildren: A Randomized, Placebo-Controlled, Double-Blind Study
Authors: Truong Tuyet Mai et al