Science has been investigating this topic for more than 70 years [1], but the positive effect of vitamin C on colds has not yet been clearly proven [2]. Studies have shown that the preventive intake of vitamin C in the general population has little or no significant effect on the occurrence of a cold [1]. But that doesn't mean it's ineffective for everyone [3]. For example participants exposed to physical stress, such as marathon runners [1] or swimmers [4] were an exception as their number of new cases was halved [1,4]. However, this is not due to a high dose of vitamin C but can be rather contributed to the acute physical conditions [1]. So it cannot be said across-the-board that vitamin C prevents colds.

However, they found out that the duration of the illness can be reduced by approx. 8% in adults and approx. 14% in children. An intake of more than 1g per day even increased the value for children up to 18% whereas no difference could be observed for adults [1].

The point of time in which is the vitamin is absorbed plays a significant role. After experiencing the first cold symptoms taking vitamin C will have no effect on the duration of the cold [1]. Furthermore Audera et al. (2001) investigated the effects of different dosages but could not observe any positive effects [5].

When taking vitamin C one should be careful as overdosing can lead to health issues. A study has shown that men who took more than 1g per day had a higher risk of developing kidney stones [6]. Vitamin C is a broadly discussed topic which also shows in an online survey on the topic of dietary supplements which was conducted by the German society for consumer research (GfK). Of the 1070 people who take supplements 52.6% also take vitamin C which is the most popular supplement [7]. Friends, family or even we ourselves take vitamin C supplements in hopes of not getting a cold during the winter.

But as research shows it is not as simple because vitamin C has no positive effect on the prevention of a cold except for smaller groups of people. However, it definitely has other advantages such as supporting our immune system [8].

You should always follow the recommended daily intake amount which can be found on the website of the German society for nutrition (DGE):

(https://www.dge.de/wissenschaft/referenzwerte/vitamin-c/).