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Upper Respiratory Tract Infection Risk

Upper respitatory tract infections (URTIs) are sicknesses that mostly affect the lung and breathing capacities, and is the cause of many cold symptoms. Supplements that reduce the risk of developing URTIs are said to promote immunity.

Research analysis led by Kamal Patel.
All content reviewed by the Examine.com Team. Published: Jul 5, 2013
Last Updated:

Things To Know & Note

Also Known As


Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect upper respiratory tract infection risk
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
grade-a Notable High See all 11 studies
The reduction in rate of sickness seen with echinacea as a daily supplement is highly effective in some instances, but subject to a high degree of variability. It is notable due to it being a comparator.
grade-c Minor - See study
Appears to be better than placebo, although it is difficult to assess potency.
grade-c Minor - See all 3 studies
There may be a minor reduction in the incidence of upper respiratory tract infections (URTIs) seen with colostrum, although more evidence is needed to confirm this activity as current trials are usually underpowered.
grade-c Minor - See study
There appears to be a reduction in the lung infection risks with garlic supplementation.
grade-c Minor - See study
Supplementation of 200 IU vitamin E in elderly persons has been noted to reduce overall occurrence of upper, but not lower, respiratory tract infections.
grade-c - - See study
grade-c - Very High See 2 studies
No significant influence on the rate of acquiring sickness
grade-c - - See study
Lack of efficacy in reducing rate of sickness
grade-c - - See study
Despite having lower sickness rates overall, the reduction seen in URTIs specifically does not appear to reach significance.
grade-d Minor Moderate See 2 studies
16 weeks supplementation reduced risk of URTI symptoms in endurance athletes undergoing winter training.
grade-d Minor - See study
Appears to reduce infection risk, although it did not appear to be overly remarkable in doing so.