Vitamin C does not prevent the common cold but may decrease the severity and duration of symptoms. Vitamin D may decrease the incidence of influenza and other viral infections as well as tuberculosis. Zinc does not prevent the common cold but also decreases severity and duration of symptoms. Probiotics do not prevent respiratory infections but may decrease severity and duration of symptoms. Xylitol decreases the risk of ear infections by 32%. Garlic may decrease the risk of the common cold, but the evidence comes from one study.

1. Dietary supplements, common cold
and other respiratory infections. Data
from meta-analyses.
21/12/20141
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Reijo Laatikainen, Authorized Nutritionist, MBA
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2. Page 2
Dietary supplements and respiratory
infections (Meta-analyses only)
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Common cold Other respiratory
infections
(bacterial &
influenza)
Authors
Vitamin C Does not prevent common
cold. Decreases severity and
duration of symptoms
? Hemilä et al.2007
Vitamin D ? Incidence of influenza and
other viral infections and
tuberculosis may decrease
Alexandra et al. 2009
Zinc Does not prevent common
cold. Decreases severity and
duration of symptoms
? Singh & Das 2011
Probiotics ? No prophylaxis effects.
Decreases severity and
duration of symptoms
Vouloumanou et al.
2009
Xylitol ? Prophylaxis decreased the
risk of otitis media by 32 %
Danhauer et al. 2010
Garlic Decreased the risk of
common cold (only 1 eligible
study)
? Lissiman et al. 2009