In the general population, vitamin C has been shown to moderately reduce the duration and severity of a cold, but not as a means to protect you from catching it in the first place. For athletes participating in activities involving extreme physical stress, vitamin C can reduce the risk of catching a cold by 52%. Supplementation after symptoms are present does not seem to affect cold duration or severity.
Unlike vitamin C, Zinc has shown more promise in lessening the duration of the common cold, when taken within 24 hours of symptom onset. Zinc lozenges were the method most commonly used during studies, and were effective at reducing cold duration at a dose of 75mg. Dosages should be split throughout the day.
Zinc is an important component for strengthening your immune system, so if you happen to be susceptible to catching colds, ensuring sufficient dietary intake is a good idea. Athletes or those who sweat a lot may also be more at risk of zinc insufficiency.
Elderberry or Sambucus is known for its antioxidant properties, and has been indicated as a potential treatment for influenza. A few human trials have shown the herb to reduce the symptoms of the flu. But many of these studies had small sample sizes and some were of low methodological quality.
If you choose to prepare elderberry yourself rather than supplementing, note that the berries must be properly cooked before ingestion, as they can cause nausea or increase the risk of cyanide toxicity when eaten in an uncooked state. The leaves and roots can also be particularly poisonous and should not be utilized when preparing supplements such as elderberry juice.
In contrast to some of the above-mentioned supplements, Pelagonium sidoides appears to be primarily used to reduce the symptoms of the cold or flu rather than as a preventative measure. This herb contains compounds known as Prodelphinidins that can help prevent bacteria from attaching to the lining of the throat and lungs.
Reaching for a supplement or two can seem like a quick and simple method for defending yourself against the cold and flu. But even the best supplements are much less important for cold prevention and treatment than basic fundamental methods like …
- Eating a healthy and nutrient-dense diet
- Sleeping enough and managing stress
- Washing your hands, and
- Getting a yearly flu shot
So as always, look to efficacious supplements as a way to bolster healthy habits, rather than as ways to combat a lifestyle that predisposes you to getting sick.