It is an accepted assumption that Vitamin C supplements boost the immune system and ward off illnesses. This theory was popularized by famous chemist and Nobel prize laureate, Linus Pauling.

However, Robert Douglas of the Australian National University and Harri Hemila of the University of Helsinki had a large-scale study reviewing 55 studies relating to Vitamin C, done 65 years ago, showed that the use of vitamin C has little effect.

They tried to discover whether vitamin C in doses of 200 mg. or more daily reduce incidence, duration, or severity of the common cold when used either as continuous medication or after the onset of cold symptoms.

All data from 1940 to 2004 were methodically screened and concluded that vitamin has little protective effect in reducing the incidence of the common cold.
They have also found out that the vitamin reduce the duration of colds by only eight percent in adults and 14 percent in children, thus, provides little justification for everyday dosage of vitamin C.

On the other hand, researchers also found out that marathon runners, skiers and soldiers exposed to icy conditions or physical stress experienced a 50% reduction in colds because of the vitamin.

While the results of this study may have contradicted a most accepted notion - or perhaps what we were made to accept for a long time, that vitamin C is effective against common cold in normal daily conditions - it is interesting to know it appears to support our body against extreme icy temperatures and physical stress.