Zinc, Vitamin D, and the Common Cold

From the Lecture series The Skeptic's Guide to Health, Medicine, and the Media

By Roy Benaroch, M.D., Emory University

Many familiar and unfamiliar minerals, vitamins, and medicines have been studied to find a definite cure for the common cold. Although zinc and vitamin D are not at the top of the list when people think about curing colds, they may be beneficial. Have scientists finally found a cure for the common cold? Read on to find out.

A sick woman lying on bed with tissues, a thermometer, and medicines around her.
Many drugs and herbs have been tested for curing the common cold, but so far, zinc and vitamin D are found reliable in preventing it. (Image: sirtravelalot/Shutterstock)

Among all the cures for the common cold, zinc seems to be more effective. There are reliable studies supporting the fact that zinc can reduce the duration of a cold. A study needs to meet certain criteria to be reliable. Did the zinc studies meet those criteria?

This is a transcript from the video series The Skeptic’s Guide to Health, Medicine, and the Media. Watch it now, on The Great Courses Plus.

Zinc for the Common Cold

A nonprofit organization called the Cochrane Collaboration reviewed 15 studies on zinc. They reviewed studies objectively to find more comprehensive answers to questions and found that taking zinc syrup every two hours reduces the duration of cold up to 50%. The review also pointed out that the intake of zinc might have side effects, including nausea, bad taste, and diarrhea.

Foods with Zinc mineral on a wooden table.
Zinc is a proven preventive for the common cold, but there are no definite cures found yet. (Image: Tatjana Baibakova/Shutterstock)

Further, an article in the Time magazine cited three studies and claimed that “Zinc Lozenges May Help Colds Go Away 3 Times Faster.” It is stated that one should take doses higher than recommended to see effects and be careful with the type of zinc.

The claim for tripling the rate of recovery is explained as to how 70% of the 200 people in three studies showed improvement after taking zinc. The results were salient as they were seen regardless of gender, race, age, or smoking status. Further, no participant had reported any side effects.

The article also gave some practical advice to look for a specific kind of zinc in the form of zinc acetate lozenges made without added citric acid. Zinc might not be a cure for the common cold, but it can definitely help banish the symptoms quicker.

Learn more about the media and the internet.

Vitamin D for the Common Cold

Vitamin C has proven ineffective for the common cold, but some studies show that vitamin D can prevent colds and flu. In 2017, NPR published an article supporting vitamin D in this regard.

Another analysis stated that respiratory infections could be reduced by higher vitamin D. Thus, people need to get more sunlight. Results from 25 studies on over 10,000 participants were reviewed to see the effect of vitamin D supplements on reducing the number of infections.

The report was strong enough as it included many studies and was published in the reliable British Medical Journal. The participants were both adults and children, and both advantages and disadvantages were covered.

The problem was that they claimed, “Vitamin D supplements seemed to reduce the risk of infection about 10 percent.” The percentage is really not that significant, and the method of calculating it is not specified. However, it is safe to take vitamin D in reasonable doses, even if it does not cure the common cold or prevent it.

Learn more about alternative medicine in the news.

A Cure for the Common Cold

In 2017, the UK’s Metro published an article entitled “We May Finally Have Found a Cure for the Common Cold.” It was a very big claim as scientists had been struggling with finding a cure for the common cold for ages. But it was not right.

The headline is vague on its own: “May Finally Have Found” does not sound so promising. The second sentence of the article just states how researchers at Edinburgh Napier University have discovered possible new treatments based on antimicrobial peptides that occur naturally in humans and animals and increase the body’s natural response to infection.

The photo shows a  stethoscope and pills on a white background.
There is no cure for the common cold, and every article that claims to offer a cure must be read much more meticulously. (Image: Kavun Halyna/Shutterstock)

The research was in the early stages, and no result or remedy was concluded. It focused on peptides, which are chains of amino acids, that had “properties that can combat rhinovirus: the main virus responsible for the common cold in humans.”

There were no drugs, no cures, and even no definite results. It was just journalism trying to make the article more attractive.

In health news, the article is usually much more important than the headline, as the real story lies in the body of the article, not the headline. The common cold has always been a controversial issue, and no definite cure has been found for it yet. Thus, whatever you read about it should be supported by strong studies, make sense, be salient, and cover both advantages and disadvantages of the suggested cure.

Common Questions about Zinc, Vitamin D, and the Common Cold

Q: Can zinc triple the rate of recovery from the cold?

Some studies suggest that taking high doses of zinc can cure the common cold three times faster. However, nausea and stomach irritation are mentioned as potential side effects.

Q: Is vitamin D effective in curing colds?

Vitamin D cannot be a cure for the common cold for everyone, but it can slightly reduce the risk of infection by about 10%. The dose must be within the allowed range.

Q: Have scientists discovered a cure for the common cold?

No, the common cold still has no definite cure despite all the studies and efforts. Nevertheless, some remedies can reduce the duration or the effects in some people.

Keep Reading
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