Imunele is manufactured by PepsiCo Russia, and contains the probiotic strains Lacticaseibacillus casei and L. rhamnosus as well as vitamins A, D3, E, B6, B9, and B12.
The RCT was conducted over three months to assess the effects of long-term consumption of a fortified fermented dairy product on URTI parameters, gastrointestinal health, and cellular immunity parameters in a healthy adult population during the spring epidemiological season of URTI.
PepsiCo R&D contracted Knomics LLC (UK) for this study, which also involved researchers from Russian institutions.
The results revealed that consumption of Imunele resulted in a significantly lower URTI incidence and frequency among females, but not in males.
There were no significant differences in terms of symptom severity in both females and males.
Published in the Journal of Functional Foods, researchers said: “Functional dairy foods with vitamins and probiotics are a promising tool for strengthening immunity of the general population.”
The study also analysed the gut microbiome composition after intake of a probiotic-fortified food, “To date, this is one of the largest placebo-controlled interventional studies of a probiotic-fortified food product to assess its effect not just on human health but also on the gut microbiome.”
“Most interventional studies assessing the impact of probiotics or probiotic-fortified foods on the microbiome have been conducted on cohorts with specific disorders, such as constipation or post-antibiotic treatment. This contrasts with the fact that most consumers of functional foods with probiotics are generally healthy.”
The study enrolled 730 healthy adults (18–50 years) and divided into three groups.
The control group received a placebo (same formulation as the fortified product but without the probiotics and vitamin fortification; blueberry premix).
The second and third groups received Imunele in strawberry premix and multi-fruit premix respectively.
Subjects were tasked to consume the test product twice daily (100 ml/serving) for three months.
The primary outcome was URTI incidence such as cold and influenza.
Subjects duration, symptoms and symptoms' severity of URTI and gastrointestinal distress (GID) were recorded.
Blood samples were collected and analysed for cellular immunity, stool samples were analysed for microbiome composition.
Effect on URTI and gastrointestinal symptoms
The findings revealed that yoghurt intake on URTI parameters were gender-specific.
Female subjects had significantly lower URTI incidence and frequency compared to the control group. For males, there were no significant differences found.
However, in both groups, there was a shortened duration of URTI events.
In terms of symptoms severity, there was no significant differences for males and females in all three groups.
These findings suggest that consumption of fortified fermented dairy foods is promising for improving immunity status within the general population.
The effect of Imunele on gastrointestinal health was less pronounced, there were no significant differences between the duration and severity of symptoms across all three groups.
Microbiome composition and cellular immunity
There were also no significant differences observed in gut microbiome composition and diversity across all three groups.
“Our results showed that addition of probiotics and vitamins did not affect the microbiome response to the yogurt intake despite the long intervention period.”
There was also no significant impact on blood and stool parameters.
Although, cellular immunity response analysis revealed that the placebo group in males had a lymphocytes (white blood cell) count compared to one of the probiotic group (group 3).
Researchers explained that the study population was relatively young (28.8. ± 9.0 years), “so it is no surprise that no complications were observed and the cellular immunity parameters remained quite within the reference ranges,
“We suggest that further studies including subjects of older age and hence lower immunity are more likely to show the effects of fortified product intake.”
The findings suggest that the fortification with probiotics and vitamins led to the decrease of several URTI-related indicators in a gender-dependent manner, its effects on gastrointestinal health and microbiome composition were not significant.
However, researchers were unsure if the observed immunity improvement was due to the intake of probiotics or vitamins.
They think vitamins may have played a larger role since the RDA values are as high as 60% for some of the vitamins, and it is known that the Russian population has a high vitamin deficiency.
They recommend that a vitamin deficiency test conducted before and after the intervention would be useful.
In addition, the daily dose of probiotics was in the order of 108 CFU, which researchers said were typically lower than those in other URTI trials, hence possibly limiting its effects.
Furthermore, the health-promoting properties of probiotics are often strain-specific, “our results do not preclude that fortification based on other strains of Lacticaseibacillus or other species might be more efficient in improving immunity.”
Further studies would be required to analyse the variability of the effects especially between the genders.
Source: Journal of Functional Foods
“Yogurt fortified with vitamins and probiotics impacts the frequency of upper respiratory tract infections but not gut microbiome: A multicenter double-blind placebo controlled randomized study”
Authors: Vera Odintsova, et al.