Assessment of vitamin C effects on pneumonia and COVID-19 using Mendelian randomization: analysis may be misleading

Hemilä, Harri; Chalker, Elizabeth

doi:10.1038/s41430-022-01091-9

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…In general, MR studies found little evidence of causative relationship between micronutrient status and COVID-19 phenotypes. In some cases conclusions of MR studies may not be reliable when the variance of a nutrient level in plasma, explained by lead SNPs is small [25 ▪ ], which is the case for vitamin C level, 1.87% on average [26]. Besides, MR studies cannot replace clinical studies, especially randomized control trials (RCTs), which provide highest quality evidence for evaluation of causative relationship between exposure and phenotype.…”

Section: Micronutrients and Coronavirus Disease 2019mentioning

confidence: 99%

Micronutrients, genetics and COVID-19

Kotur

Stanković

Pavlović

2023

Current Opinion in Clinical Nutrition &Amp; Metabolic Care

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Purpose of reviewMarked inter-individual differences in the clinical manifestation of coronavirus disease 2019 (COVID-19) has initiated studies in the field of genetics. This review evaluates recent genetic evidence (predominantly in the last 18 months) related to micronutrients (vitamins and trace elements) and COVID-19.Recent findingsIn patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), altered circulating levels of micronutrients may serve as prognostic markers of disease severity. Mendelian randomization (MR) studies did not find significant effect of variable genetically predicted levels of micronutrients on COVID-19 phenotypes, however, recent clinical studies on COVID-19 point out to vitamin D and zinc supplementation as a nutritional strategy to reduce disease severity and mortality. Recent evidence also points to variants in vitamin D receptor (VDR) gene, most notably rs2228570 (FokI) “f” allele and rs7975232 (ApaI) “aa” genotype as poor prognostic markers.SummarySince several micronutrients were included in the COVID-19 therapy protocols, research in the field of nutrigenetics of micronutrients is in progress. Recent findings from MR studies prioritize genes involved in biological effect, such as the VDR gene, rather than micronutrient status in future research. Emerging evidence on nutrigenetic markers may improve patient stratification and inform nutritional strategies against severe COVID-19.

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Section: Micronutrients and Coronavirus Disease 2019mentioning

confidence: 99%

Micronutrients, genetics and COVID-19

Kotur

Stanković

Pavlović

2023

Current Opinion in Clinical Nutrition &Amp; Metabolic Care

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Vitamin C and the risk of atrial fibrillation: Mendelian randomization study may be misleading

Hemilä

Chalker

2022

Clinical Nutrition

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Vitamin C reduces the severity of common colds: a meta-analysis

Hemilä,

Chalker

2023

BMC Public Health

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Background Randomized trials have shown that vitamin C shortens the duration of common colds. Some trials reported greater effects on severe cold symptoms compared with mild symptoms. This review systematically compares the effects of vitamin C on severe and mild common cold symptoms. Methods We included all placebo-controlled trials of orally administered vitamin C in doses of at least 1 g/day for the common cold for people in good health at baseline. The analysis was restricted to trials which reported both the total duration of the common cold, and the severity of the common cold measured using severity scales, the duration of more severe stages of the cold, or proxies for severe colds such as days indoors. Findings were pooled using the inverse variance, fixed effect options of the metacont function of the R package meta to calculate the ratio of means estimate. Results Fifteen comparisons from 10 trials which reported both mild and severe symptoms were identified. All trials were randomized and double-blind. Compared to placebo, vitamin C significantly decreased the severity of the common cold by 15% (95% CI 9–21%). The direct comparison of the effect of vitamin C on mild and severe symptoms was limited to five comparisons which found that vitamin C had a significant benefit on the duration of severe symptoms. In this subset, there was a significant difference in the size of the effect of vitamin C on the overall duration of colds versus the duration of severe colds (P = 0.002), and vitamin C had no significant effect on the duration of mild symptoms. Conclusions The common cold is the leading cause of acute morbidity and a major cause of absenteeism from work and school. However, absenteeism is dependent on the severity of symptoms. The finding that vitamin C may have a greater effect on more severe measures of the common cold is therefore important. Further research on the therapeutic effects of vitamin C on the common cold should measure outcomes of differing levels of severity.

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Assessment of vitamin C effects on pneumonia and COVID-19 using Mendelian randomization: analysis may be misleading

Cited by 3 publications

References 11 publications

Micronutrients, genetics and COVID-19

Micronutrients, genetics and COVID-19

Vitamin C and the risk of atrial fibrillation: Mendelian randomization study may be misleading

Vitamin C reduces the severity of common colds: a meta-analysis

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