Table 1.
Characteristics of the Studies Included.
| First Author/Year/Country | Nutrients/Lifestyle Eating Behaviors | Type of Study | Sample | Principal Intervention | Principal Results |
|---|---|---|---|---|---|
| Sabico et al. (2020)/Saudi Arabia | Vitamin D3 | Multi-center RCT | 36 IG, 33 CG | Two weeks oral 5000 IU for IG or 1000 IU for CG | Significantly shorter days needed to resolve cough (6.2 ± 0.8 vs. 9.1 ± 0.8; p = 0.007) and ageusia (11.4 ± 1.0 vs. 16.9 ± 1.7; p = 0.035) |
| Murai et al. (2020)/Brazil | Vitamin D3 | Multi-center RCT | 120 IG, 120 CG | Single oral dose of 200,000 IU of vitamin D3 or placebo | No significant differences found for hospital mortality, ICU admission, and mechanical ventilation support |
| Thomas et al. (2020)/USA | VIT-C GZ |
Multi-center RCT | 48 VIT-C, 58 GZ, 58 both, 50 usual care | 8000 mg of VIT-C (2–3 times/day with meals) 50 mg of GZ at bedtime, both therapies, or usual care | No significant differences in primary endpoint achievement among groups (p = 0.45) |
| Tan et al. (2020)/Singapore | VIT-D Magnesium and B12 |
Retrospective cohort | 17 DMB IG, 26 CG | 1000 IU D3, 150 mg/d magnesium, and 500 mcg/d vitamin B12 orally for 14 days after hospital admission | DMB exposure associated with lower odds of oxygen therapy or ICU support in univariate and multivariate analysis |
| Caballero-García et al. (2020)/Spain | VIT-D | Pilot double-blind RCT | 15 IG, 15 CG | 6 weeks of treatment with VIT-D (2000 IU/day) | Increase in serum creatine kinase levels |
| Rastogi et al. (2020)/India | Cholecalciferol | RCT | 16 IG, 24 CG | 60,000 IU oral per day of cholecalciferol for 7 days targeting 25OH-D > 50 ng/ml | Mean duration of SARS-CoV-2 negativity similar in both groups (p = 0.283) |
| Maghbooli et al. (2020)/Iran | Cholecalciferol | Multi-center RCT | 53 IG (24 completed), 53 CG (19 completed) | 25 μg of 25OH-D daily | At 30 and 60 days, higher proportion of sufficient 25OH-D concentration in IG compared to CG |
| Annweiler et al. (2020)/France | VIT-D | Multi-center RCT | 127 high-dose IG, 127 standard-dose CG | High-dose (400,000 IU) and standard-dose (50,000 IU) vitamin D3 | No maintained protective effect at 28 days; similar death rates between high-dose and standard-dose groups (p = 0.29) |
| Mariani et al. (2020–2021)/Argentina | VIT-D | Multi-center RCT | 115 IG, 103 CG | 500,000 IU of vitamin D3 (5 capsules of 100,000 IU) | No significant differences for ICU admissions or in-hospital mortality between groups |
| De Niet et al. (2020–2021)/Belgium | VIT-D | Single-center RCT | 26 IG, 24 CG | 25,000 IU per day of VIT-D for 4 days, then 25,000 IU per week for up to 6 weeks | No hospitalizations in IG after 21 days compared to 14% in CG; no significant mortality differences |
| Karonova et al. (2020–2021)/Russia | Cholecalciferol | Single-center RCT | 56 IG, 54 CG | Cholecalciferol at 50,000 IU on first and eighth days of hospitalization | IG showed higher neutrophil and lymphocyte counts, lower C-RP level on ninth day of hospitalization |
| Majidi et al. (2020)/Iran | VIT-C | Single-center RCT | 31 IG, 69 CG | One capsule of 500 mg of VIT-C daily for 14 days | Higher survival rate in IG (p = 0.028) |
| Beigmohammadi et al. (2020)/Iran | Multi-vitamins (A-B-C-D-E) | Single-center RCT | 30 IG, 30 CG | 25,000 IU daily of vitamins A, 600,000 IU once during study of VIT-D, 300 IU twice daily of VIT-E, 500 mg four times daily of VIT-C, Vit-B complex for 7 days | Significant improvements in serum levels of vitamins, ESR, C-RP, IL6, TNF-a, and SOFA score after intervention |
| Doaei et al. (2020)/Iran | Omega-3 | Single-center RCT | 28 IG, 73 CG | 1000 mg omega-3 daily containing 400 mg EPA and 200 mg DHA added in Enteral Formula for 2 weeks after ICU admission | Higher 1-month survival rate, arterial pH levels, bicarbonate, and base excess in IG compared to CG |
| Gutiérrez-Castrellón et al. (2020)/Mexico | Probiotics | Single-center RCT | 147 IG, 146 CG | Strains Lactiplantibacillus plantarum KABP022, KABP023, KAPB033, Pediococcus acidilactici KABP021 (totaling 2 × 109 CFU) | Complete symptomatic remission and viral clearance at day 30 higher in IG [RR: 1.89 (95% CI 1.40–2.55); p < 0.001] |
| Bhutani et al. (2020)/USA | Lifestyle eating behaviors | Cross-sectional study | 727 | Online survey | Mean body weight gain of 0.62 kg during lockdown, increased BMI (p < 0.01) |
| Skotnicka et al. (2020)/Poland-Austria-United Kingdom | Lifestyle eating behaviors | Retrospective observational study | 1071 | Online survey | Increased frequency of eating, ordering ready meals, eating sweets, fruits, and drinking alcohol; decreased physical activity, increased body mass |
| Cicero et al. (2020)/Italy | Lifestyle eating behaviors | Cross-sectional study | 359 | Phone interview | No significant changes in lifestyle or BMI (p = 0.361) |
| Mascherini et al. (2020)/Italy | Lifestyle eating behaviors | Cross-sectional study | 1383 | Online survey | Increase in body weight from 64.9 ± 13.8 to 65.3 ± 14.1 kg (p < 0.001) |
| Chin et al. (2020)/Malaysia | Lifestyle eating behaviors | Cross-sectional study | 1319 | Online survey | 41.2% felt eating patterns were healthier, 36.3% reduced physical activities, 25.7% had lower sleep quality |
| Paltrinieri et al. (2020)/Italy | Lifestyle eating behaviors | Cross-sectional study | 1826 | Online survey | Working remotely or in usual modalities positively influenced lifestyle, reducing likelihood of worsening physical activity (OR 0.50; 95% CI 0.31–0.79) |
Legend. IG: intervention group; CG: control group; RCT: randomized controlled trial; IU: international units; VIT-C: vitamin C; VIT-D: vitamin D; VIT-E: vitamin E; GZ: gluconate zinc; DMB: vitamin D, magnesium, and B12; 25OH-D: 25-hydroxyvitamin D; C-RP: C-reactive protein; IL6: interleukin 6; TNF-a: tumor necrosis factor-alpha; ICU: intensive care unit; RR: relative risk; CI: confidence interval; SOFA: sequential organ failure assessment; EPA: eicosapentaenoic acid; DHA: docosahexaenoic acid; CFU: colony-forming units; BMI: body mass index; OR: odds ratio.