When the days get shorter and colder, cold season comes. So what to do? The tricks known from the Corona era offer protection: mask, ventilation, distance. But there is no vaccination; the flu vaccination only works against the real flu, influenza.
Even though a cold is usually more harmless than the flu, most people would be happy if they also had something on hand to combat the annoying cold symptoms such as a runny nose, cough, sore throat and headache.
In this situation, many people look for relief in tried and tested home remedies or widely advertised nutritional supplements.
Zinc in particular raises high expectations. The vital trace element fulfills numerous tasks in the body; it is particularly important for a well-functioning immune system. Since our body cannot produce zinc itself or store it, we have to get it daily – through food, as a supplement or both together.
Zinc actually helps a bit
So it’s no surprise that virtually every over-the-counter cold medicine contains zinc in addition to vitamins. The trace element owes its good reputation primarily to a scientific analysis that went back several years: in 2011, researchers from the renowned Cochrane Institute evaluated all major studies on the topic came to the end: Zinc actually helps a bit. Those who start taking an increased amount of zinc within the first 24 hours of a cold are, on average, less sick for a day and more likely to recover after a week than someone who only takes a placebo.
Zinc does not seem to have any significant effect when taken as a preventive measure. Zinc is also of no use against any other illness.
However, for preventative medicine and nutritionist David Fäh from the Bern University of Applied Sciences, the Cochrane study raises questions – particularly those about the possible side effects and health risks of long-term use with increased zinc dosages.
Since the increased amount of zinc can hardly be consumed through normal food, this would have to be done primarily through dietary supplements. And in a very specific dosage form: as a lozenge. The zinc should be able to act locally on the mucous membranes of the throat for a certain amount of time in order to develop its effect. However, many of the common cold remedies with zinc are swallowable – and therefore de facto useless.
In fact, zinc also has its pitfalls. Fitness athletes sometimes swallow large amounts of zinc tablets with the intention of promoting testosterone production and thus building more muscle. The trace element is also said to have this effect, especially in relevant internet forums.
However, excessive intake of zinc can hinder the body’s absorption of copper. And because copper is important for the absorption of iron, iron deficiency and, as a result, anemia can occur.
The Swiss nutritionist Samuel Mettler, who specializes in sports nutrition, also repeatedly encounters athletes who take unnecessarily high supplementation, including zinc, over a long period of time – and thus accept negative interactions with other minerals such as iron. In elite sport, it can be crucial if a cold can be weakened and shortened. However, here too, only short-term, very targeted supplementation via lozenges is of any use. “Zinc, on the other hand, is certainly not beneficial for building muscle,” explains Mettler. “In bad cases, it can even be harmful to your health.”
When it comes to cold protection, fellow expert David Fäh is also cautious about making recommendations regarding zinc: “In my opinion, the small benefit is disproportionate to the possible risks. I clearly advise against long-term use over several months.”
It makes more sense to get enough zinc through a balanced diet and thus support the immune system. “Then there will definitely be no overdoses.”