colds: Does vitamin C protect against a flu-like infection?


Cold, cough, headache: A flu-like infection, the “simple” cold can be caught several times a year. Some humans swear to be able to prevent a cold with the income of Vitamin C preparations or fight the illness thereby. But does this really help?

During the cold season you can hear coughing and blowing in many places. A runny nose, watery eyes or headaches are unpleasant symptoms of a cold. Some people use preparations with vitamin C in the belief that they can prevent a flu-like infection. But does this really help?

As the Institute for Quality and Efficiency in Health Care (IQWiG) explains on its portal “”, a certain amount of vitamin C is essential for good health. Most humans take up however already with the daily food completely sufficient quantities. Vitamin C (ascorbic acid) is contained for example in fruits and vegetables, particularly in citrus fruits and berries. By a Vitamin C deficiency caused illnesses as for example the scurvy do not occur in this country today practically any longer.

Sufficient vitamin C through nutrition

Nevertheless, some people take vitamin C preparations every day to prevent diseases, especially colds. Some of these preparations contain more than one gram of vitamin C and thus more than ten times the recommended daily dose. Because the body cannot store vitamin C, the excess usually ends up in the toilet with the urine within a few hours. According to the German Federal Institute for Risk Assessment (BfR), a daily intake of 100 milligrams with food is sufficient.

Researchers from the international research network Cochrane Collaboration have been investigating for years whether taking large amounts of vitamin C can protect against colds or alleviate them. The researchers evaluated controlled studies in which vitamin C was compared with a preparation without an active substance (placebo).

According to the IGWiG in 29 studies, in which altogether well 11,000 adults and children had participated, it was examined whether the regular income of at least 200 mg Vitamin C protects against colds. In most studies, a dose of 1,000 milligrams or more of vitamin C per day was tested. Some of the participants took vitamin C over a period of several years.

The scientific studies showed that a long-term daily intake did not prevent the common cold, but it did shorten the duration of the cold by about ten percent. This means, for example, that one cold lasted only nine days instead of ten. In addition, the long-term intake of vitamin C was able to alleviate the symptoms of the cold a little. These results were also confirmed by other research groups, especially for children. In adults who only started taking vitamin C at the onset of their colds, the duration of the illness was not shortened.

Some of the studies investigated the preventive effect of vitamin C in people who were exposed to very heavy physical exertion through sport for short periods of time, often in combination with cold weather. These included marathon runners and soldiers doing winter training in the mountains. In the studies, the participants started taking vitamin C as a preventive measure two to three weeks before the very heavy physical strain. According to the data, about half of all colds could be prevented.

Vitamin C for the prevention of colds?

But what can really work preventatively is thorough hand hygiene. Due to the corona pandemic, more attention is currently being paid to this anyway. Hands are constantly in contact with pathogens, whether through door handles, light switches or objects that many people have touched. It becomes problematic when the germs continue to enter the mucous membranes via the hands. As explained on Austria’s public health portal “”, Florian Thalhammer from the Clinical Department of Infections and Tropical Medicine at the Medical University (MedUni) of Vienna estimates that up to 80 percent of all infectious diseases are transmitted via the hands: “A good example are colds and flu. Washing hands massively reduces the risk, as the number of germs can be reduced by more than 99 percent”. (ad)

WashingtonNewsday Health and Wellness.


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