A common, inexpensive supplement could shorten the duration of the cold virus by up to two days, a new analysis suggests.
The scientists investigated previous data from eight trials involving more than 900 volunteers into whether zinc could relieve cold symptoms.
The supplement, which is available in supermarkets and costs as little as $5 a bottle, has long been hailed as a “natural” remedy for colds and coughs by health gurus on social media.
But for the first time, a benchmark review conducted by experts from the prestigious The Cochrane Institute in the United Kingdom has given some credence to the supposed benefits.
The review concluded that zinc could shorten a cold by about two days, although the evidence supporting this finding was “weak.”
Cheap, Common Supplement May Help Fight Cold, Study Suggests
Experts warned, however, that the capsules can also cause a number of side effects, including intestinal problems, nausea and an unpleasant taste in the mouth.
Zinc, a mineral found in foods such as chickpeas, cashews and some shellfish, is essential for healthy DNA, building protein and boosting the immune system.
Scientists have long suspected it has infection-fighting benefits, as laboratory studies have shown it can stop viral cells from replicating in the mouth and nose.
This limits the extent to which a virus can spread throughout the body.
Zinc is popular in the US as a supplement to help shorten the duration of a cold. It sells at popular stores for $12.
Dr Daryl Nault, a health sciences professor who was involved in the review, said: “Although many trials have been done with zinc, approaches vary, making it difficult to draw conclusions with certainty.”
However, he added that the supplement could “potentially shorten the illness by a few days” if people are willing to risk “possible unpleasant side effects.”
He added: “The best advice is to consult your doctor if you are not feeling well and inform him or her if you use any supplements.”
Dr Susan Wieland, researcher and lead author of the review, added: “The evidence on zinc is far from solid: we need more research before we can be confident in its effects.”
“Further studies focusing on the most promising types and doses of zinc products are important for patients and will allow us to understand whether zinc may have any use in treating the common cold.”
Zinc products have been marketed as a treatment for the common cold since the 1980s and are particularly popular in the United States.
Walgreens has a ‘Zinc Cold Therapy’ on shelves for $11.49, while CVS carries a ‘Cold Remedy’ containing zinc for $11.99. Popular supplement company Nature Made sells 30 mg tablets for $5.79.
In the study, scientists also investigated whether zinc could reduce the severity of cold symptoms, but found no “hard” evidence to support this.
They also reviewed 15 studies on whether zinc could prevent a cold, but found “no clear evidence” that it did.