Acute respiratory infection
Supplements studied for Acute respiratory infection.
Overview
SupplementDEX lists 3 supplements studied for acute respiratory infection across 24 trials. The strongest indexed signals include Vitamin D, Garlic, Zeaxanthin. See the heatmap and evidence reviews below for full ratings across all supplements.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Vitamin D | ★★★★★ | Medium |
| Garlic | ★★★★★ | Low |
| Zeaxanthin | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
3 supplements for , and rated at least stars. All purchase bands. No minimum star filter.
Vitamin DView supplement →
Consider purchase·★★★★★
How we scored this▸
- Taking vitamin D supplements helps reduce the chance of respiratory infections in children, but it does not seem to help adults or older adults.
- Children who take vitamin D have about 30% fewer respiratory infections, especially if they take it daily or weekly rather than less often in large doses.
- However, the studies vary, and some effects might be due to bias.
- Giving vitamin D during pregnancy to the mother does not clearly reduce infections in babies, even though higher vitamin D levels in pregnancy are linked to fewer infections.
- Experts sometimes recommend giving children vitamin D supplements or fortified foods to help lower infection risk, even if blood vitamin D levels aren't tested.
Browse 22 studies·11 meta-analyses
RCTThe effects of prenatal vitamin D supplementation on respiratory and allergy-related outcomes in children: A systematic review and meta-analysis of randomized controlled trials2025
A meta-analysis of 7 RCTs (3,958 mother-infant pairs) found prenatal vitamin D did not reduce childhood RTI, asthma, wheeze, eczema, or allergy.
- Effect
- No Benefit
- Population
- Pregnant women
MetaEffect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis2024
A meta-analysis of 18 studies in 36,707 dark-skinned individuals found no significant effect of vitamin D supplementation on acute respiratory tract infections (OR 1.40).
- Effect
- No Benefit
- Population
- Adults
MetaOptimal methods of vitamin D supplementation to prevent acute respiratory infections: a systematic review, dose-response and pairwise meta-analysis of randomized controlled trials2024n=49,320
A meta-analysis of 43 RCTs (49,320 participants) found daily vitamin D 400–1200 IU may modestly prevent ARIs in subgroups, but overall supplementation showed no significant benefit.
- Effect
- No Benefit
- Dose
- 400–1200 IU/day
- Participants
- 49,320
GuideVitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline2024
The 2024 Endocrine Society guideline suggests empiric vitamin D for children, adults ≥75, pregnancy, and high-risk prediabetes, but not routine use in healthy younger adults.
- Population
- Pregnant women
- Ages
- 1–18
MetaVitamin D supplementation for prevention of acute respiratory infections in older adults: A systematic review and meta-analysis2024n=41,552
A meta-analysis of 12 RCTs in 41,552 older adults found vitamin D supplementation probably did not reduce acute respiratory infection incidence (RR 0.99).
- Effect
- No Benefit
- Population
- Older adults
- Participants
- 41,552
RCTVitamin D supplementation and hospitalization for infection in older adults: A post-hoc analysis of data from the Australian D-Health Trial2023
In the D-Health post-hoc analysis of 21,315 Australians aged 60–84 given 60,000 IU/month for 5 years, vitamin D did not reduce infection hospitalizations but cut extended stays >6 days.
- Effect
- No Benefit
- Duration
- 5 years
- Dose
- 60–84 g/day
- Population
- Women
- Ages
- 60–84
MetaEfficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials2022n=30
A meta-analysis of 30 RCTs (30,263 participants) found vitamin D supplementation had no significant effect on prevention of acute respiratory infections overall (RR 0.96).
- Effect
- No Benefit
- Participants
- 30
MetaVitamin D supplementation in pregnant women or infants for preventing allergic diseases: a systematic review and meta-analysis of randomized controlled trials2022
A meta-analysis of 7 RCTs found prenatal or infant vitamin D supplementation did not reduce risk of asthma, wheeze, eczema, allergic rhinitis, or food allergy.
- Effect
- No Benefit
- Population
- Women
ObservationalThe effect of vitamin D supplementation on acute respiratory tract infection in older Australian adults: an analysis of data from the D-Health Trial2021n=315
In the D-Health Trial of older Australian adults given monthly vitamin D for up to 5 years, supplementation did not reduce respiratory infection incidence, duration, or severity.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 315
- Ages
- 60–79
MetaVitamin D supplementation to prevent acute respiratory infections: a systematic review and meta-analysis of aggregate data from randomised controlled trials2021n=802
An updated meta-analysis of 43 vitamin D RCTs found supplementation did not significantly reduce the odds of acute respiratory infections compared with placebo.
- Effect
- No Benefit
- Dose
- 2000 IU/day
- Participants
- 802
- Ages
- 0–95
ObservationalVitamin D Insufficiency and Deficiency and Mortality from Respiratory Diseases in a Cohort of Older Adults: Potential for Limiting the Death Toll during and beyond the COVID-19 Pandemic?2020n=9,940
In an older-adult cohort, vitamin D insufficiency and deficiency were associated with higher mortality from respiratory diseases, suggesting a link warranting further study.
- Effect
- No Benefit
- Population
- Women
- Participants
- 9,940
- Ages
- 50–75
RCTVitamin D and Acute Respiratory Infections-The PODA Trial2019n=9
In the PODA RCT of 260 older African American women maintained at 25(OH)D >30 ng/mL for 3 years, vitamin D did not prevent acute respiratory infections versus placebo.
- Effect
- No Benefit
- Duration
- 3 years
- Population
- Women
- Participants
- 9
- Ages
- 60+
MetaVitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis2019n=11,321
An IPD meta-analysis of 25 RCTs (11,321 participants) found vitamin D reduced acute respiratory infection risk (aOR 0.88), especially with daily dosing and low baseline 25(OH)D.
- Effect
- Benefit
- Participants
- 11,321
- Ages
- 0–95
RCTEffect of Vitamin D Supplementation on Recurrent Wheezing in Black Infants Who Were Born Preterm: The D-Wheeze Randomized Clinical Trial2018n=300
In 300 preterm black infants randomized to sustained 400 IU/day versus diet-limited vitamin D for 12 months, sustained supplementation reduced recurrent wheezing (RR 0.66).
- Effect
- Benefit
- Duration
- 28–36 weeks
- Dose
- 400 IU/day
- Population
- Children/adolescents
- Participants
- 300
- Ages
- 28–36 weeks gestation
MetaPrenatal vitamin D status and respiratory and allergic outcomes in childhood: A meta-analysis of observational studies2018
A meta-analysis of 34 observational studies found higher prenatal 25(OH)D inversely associated with offspring respiratory tract infections but not with asthma or allergy outcomes.
- Effect
- Benefit
- Population
- Pregnant women
RCTHigh-Dose Monthly Vitamin D for Prevention of Acute Respiratory Infection in Older Long-Term Care Residents: A Randomized Clinical Trial2017n=107
In 107 long-term care residents given 100,000 IU/month vitamin D for 12 months, ARI incidence fell (IRR 0.60) but fall rates increased significantly versus standard-dose controls.
- Effect
- Benefit
- Duration
- 12 months
- Dose
- 100000 IU/day
- Population
- Older adults
- Participants
- 107
- Ages
- 60+
MetaInfant Respiratory Tract Infections or Wheeze and Maternal Vitamin D in Pregnancy: A Systematic Review2017
A systematic review found prenatal vitamin D supplementation associated with reduced offspring wheeze (RR 0.81 in 3 RCTs), with one high-dose trial also reducing RTI doctor visits.
- Effect
- Benefit
- Dose
- 2000 IU/day
- Population
- Pregnant women
- Ages
- 0–5
MetaVitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials2017n=8,406
A systematic review of 43 prenatal vitamin D RCTs (8,406 participants) found supplementation increased birth weight and reduced wheeze by age 3 but showed limited maternal clinical benefit.
- Effect
- Benefit
- Dose
- 600 IU/day
- Population
- Pregnant women
- Participants
- 8,406
MetaVitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data2017n=321
An IPD meta-analysis of 25 RCTs (11,321 participants) found vitamin D supplementation safely reduced acute respiratory tract infection risk overall (aOR 0.88).
- Effect
- Benefit
- Dose
- 10–25 mcg/day
- Population
- Pregnant women
- Participants
- 321
- Ages
- 0–95
RCTReduced primary care respiratory infection visits following pregnancy and infancy vitamin D supplementation: a randomised controlled trial2015n=87
In a New Zealand RCT of 260 mother-infant pairs given up to 2000/800 IU/day vitamin D, the higher-dose group had fewer primary care respiratory infection visits by age 18 months.
- Effect
- Benefit
- Duration
- 6–18 months
- Dose
- 800 IU/day
- Population
- Women
- Participants
- 87
- Ages
- 6–18
RCTRandomized trial of vitamin D supplementation and risk of acute respiratory infection in Mongolia2012n=244
In 247 vitamin D–deficient Mongolian schoolchildren given 300 IU/day in winter, supplementation halved parent-reported acute respiratory infections versus control milk.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 300 IU/day
- Population
- Children/adolescents
- Participants
- 244
RCTVitamin D for prevention of respiratory tract infections: A systematic review and meta-analysis2012
A meta-analysis of 5 RCTs found vitamin D supplementation significantly reduced respiratory tract infection events (OR 0.58), with consistent benefit in children's trials.
- Effect
- Benefit
- Population
- Adults
GarlicView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Early research on garlic for acute respiratory infection is limited.
- A clinical trial in children evaluating whether long-acting garlic tablets (Allicor) reduce the incidence of acute respiratory viral infections compared with control.
- More studies are needed before any benefit can be considered reliable.
Browse 1 study
RCT[Effect of long-acting garlic tablets "allicor" on the incidence of acute respiratory viral infections in children]2003n=172
In Russian children (ages 7–16), long-acting garlic tablets (600 mg/day) reduced acute respiratory infection rates 2–4 fold in an open study and 2-fold versus benzimidazole in a double-blind trial.
- Effect
- Benefit
- Duration
- 5 months
- Dose
- 600 mg/day
- Population
- Children/adolescents
- Participants
- 172
- Ages
- 7–16
ZeaxanthinView supplement →
Do not purchase·★★★★★
How we scored this▸
- It is not clear whether taking zeaxanthin by mouth helps prevent or treat respiratory infections.
- Studies in older adults show that higher levels of zeaxanthin in the blood do not seem to lower the chance of getting respiratory infections or reduce their severity.
- More research is needed to understand if zeaxanthin supplements provide any benefit for respiratory infections.
Browse 1 study
RCTPlasma carotenoid concentrations in relation to acute respiratory infections in elderly people2004n=652
In 652 elderly adults, those in the highest beta-carotene quartile had 29% lower acute respiratory infection incidence (IRR 0.71) versus the lowest quartile; lutein/zeaxanthin showed no association.
- Effect
- No Benefit
- Population
- Older adults
- Participants
- 652
- Ages
- 60+
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Vitamin D | ★★★★★68% | 22 | 11 | 92% |
| Garlic | ★★★★★44% | 1 | 0 | 4% |
| Zeaxanthin | ★★★★★32% | 1 | 0 | 4% |