Effects of Gut Microbiome Modulation on Reducing Adverse Health Outcomes among Elderly and Diabetes Patients during the COVID-19 Pandemic: A Randomised, Double-Blind, Placebo-Controlled Trial (IMPACT Study).

Nutrients. 2023;15(8)
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Worldwide, the coronavirus disease 2019 (COVID-19) pandemic has posed a substantial challenge in terms of its induced morbidity and mortality to the general population. Patients with diabetes and elderly individuals are particularly vulnerable during the pandemic. The aim of this study was to assess the efficacy of a novel microbiome immunity formula (SIM01) in reducing adverse health outcomes in the elderly and patients with type two diabetes mellitus during the COVID-19 pandemic. This study was a double-blind, randomised, parallel-arm, placebo-controlled trial. Participants were randomly assigned to receive a microbiome immunity formula (SIM01) or placebo in a 1:1 ratio for three months. Results showed that SIM01, could reduce adverse health outcomes, improve quality of life, and restore gut dysbiosis among elderly subjects and patients with type two diabetes during the COVID-19 pandemic. In fact, SIM01 not only replenished Bifidobacteria but also favoured the coexistence of other beneficial species. Authors conclude that their findings provide significant societal implications for strategies that could protect these vulnerable individuals during the COVID-19 pandemic.


Gut microbiota is believed to be a major determinant of health outcomes. We hypothesised that a novel oral microbiome formula (SIM01) can reduce the risk of adverse health outcomes in at-risk subjects during the coronavirus disease 2019 (COVID-19) pandemic. In this single-centre, double-blind, randomised, placebo-controlled trial, we recruited subjects aged ≥65 years or with type two diabetes mellitus. Eligible subjects were randomised in a 1:1 ratio to receive three months of SIM01 or placebo (vitamin C) within one week of the first COVID-19 vaccine dose. Both the researchers and participants were blinded to the groups allocated. The rate of adverse health outcomes was significantly lower in the SIM01 group than the placebo at one month (6 [2.9%] vs. 25 [12.6], p < 0.001) and three months (0 vs. 5 [3.1%], p = 0.025). At three months, more subjects who received SIM01 than the placebo reported better sleep quality (53 [41.4%] vs. 22 [19.3%], p < 0.001), improved skin condition (18 [14.1%] vs. 8 [7.0%], p = 0.043), and better mood (27 [21.2%] vs. 13 [11.4%], p = 0.043). Subjects who received SIM01 showed a significant increase in beneficial Bifidobacteria and butyrate-producing bacteria in faecal samples and strengthened the microbial ecology network. SIM01 reduced adverse health outcomes and restored gut dysbiosis in elderly and diabetes patients during the COVID-19 pandemic.

Lifestyle medicine

Patient Centred Factors : Mediators/Gut microbiome
Environmental Inputs : Nutrients ; Microorganisms
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Stool
Bioactive Substances : Probiotics

Methodological quality

Jadad score : 5
Allocation concealment : Yes