Efficacy of nutraceuticals (probiotics or prebiotics or synbiotics) in the prevention or treatment of COVID -19: a systematic review and meta-analysis

Abstract

Nutraceuticals have generated an interest among clinicians for their applicability in the prevention and treatment of many ailments. Literature suggests the possible role of nutraceuticals in COVID-19. However, substantial uncertainty related to their safety and efficacy still exists. The aim of this study is to assess the efficacy and safety of nutraceuticals in preventing or treating COVID-19. We searched electronic databases, registries, websites, and e-libraries of development agencies. We included randomized controlled trials (RCTs), quasi-experiments, pre-post studies, and other experimental study designs. We assessed the risk of bias (RoB) using the RoB2 tool for RCTs and the ROBINS-I tool for non-RCTs. We assessed the overall certainty of the evidence using GRADEpro GDT. The outcomes assessed were the number of COVID-19 cases, change in disease severity, days of hospitalization, deaths, and adverse events. We performed the last search on 13th December 2023. After screening 481 studies, our analysis of five revealed one study with ‘low risk’ and four studies with ‘some concerns’ regarding bias. Our findings indicated that nutraceuticals did not significantly reduce COVID-19 mortality; their effect on hospitalization duration was uncertain. Furthermore, our assessment found no substantial evidence of increased adverse effects with probiotic use (RR 0.11, 95% CI 0.01 to 1.89, P = 0.13). Importantly, none of the studies investigated nutraceuticals’ preventive effects or their role in mitigating COVID-19 severity. There is limited evidence available on the use of nutraceuticals (probiotics, prebiotics, or synbiotics) for the treatment and prevention of COVID-19. Conducting methodologically robust RCTs with large population samples is recommended.PROSPERO REGISTRATION ID CRD42021284923

Keywords:

• COVID-19
• Probiotics
• nutraceuticals
• mortality
• days of hospitalization

REVIEWING EDITOR:

• M. Luisa Escudero-Gilete, Universidad de Sevilla, Spain

SUBJECTS:

• Nutrition
• Nutraceuticals & Functional Foods

Acknowledgement

Dr. Rekha Sinha, International Life Sciences of India (ILSI).

Authors’ contributions

Concept and ideation: APS; Protocol development: APS and MNK; Literature search: AG and SZQ; Screening and selection of studies: SU and MW; Data extraction: SU and MW; Assessment of risk of bias of included studies: APS and MNK; Meta-analysis: AG; Assessment of Quality of Evidence: SZQ; Overall preparation of the manuscript: APS, MNK and SU with inputs from all the other reviewers.

Differences between protocol and review

In the protocol, we had planned to assess the risk of bias for RCTs using Cochrane’s Risk of Bias Tool. However, we used the RoB 2 tool, the revised tool for assessing the risk of bias in randomized trials (Sterne et al., 2019). We had not kept ‘Comparison 3: Nutraceuticals (Probiotics or prebiotics or synbiotics) as an adjunct to standard treatments verses placebo’ as a Comparison in the protocol. However, one trial (Rathi et al., 2021) reported a ‘Free of fatigue’ outcome for this comparison group. We felt that readers might be interested in understanding the efficacy of probiotics in reducing fatigue. Hence, we have added ‘Free of fatigue’’ as a secondary outcome under this comparison group.

Disclosure statement

The authors report there are no competing interests to declare.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Additional information

Funding

This SR was funded by the International Life Sciences Institute (ILSI), India under Grant 5/7/ILSI-India/2021-RBMCH, Special Grant Project No.252.