Study finds high-dose vitamin C does not prevent common cold

As winter begins, calls to take large doses of vitamin C to prevent colds and flu become widespread, with pharmacies promoting supplements as a way to boost immunity.

This belief is linked to American scientist Linus Pauling, a two-time Nobel laureate, who in his 1970 book recommended taking between 1,000 and 2,000 mg of vitamin C daily to maintain health and prevent colds.

Although Pauling was neither a doctor nor a nutritionist, his views popularized the idea that high doses of vitamin C could ward off colds. However, his conclusions were later criticized due to the poor quality of the studies he cited.

Recent scientific evidence indicates that vitamin C’s effect on the common cold is limited, with no proof it prevents illness in the general population.

A 2023 meta-analysis involving 2,736 people found that regular vitamin C intake may reduce cold symptom severity by 15 percent, but its impact on symptom duration was minimal.

A 2013 meta-analysis also showed that taking 200 mg daily did not reduce the number of colds in most people, though greater benefits were seen among athletes and military personnel.

Most people need only small amounts of vitamin C, which can be easily obtained from food. In Australia, the recommended daily intake for adults is just 45 mg, available in half an orange or a small serving of broccoli.

Consistently taking more than 1,000 mg per day may cause side effects such as diarrhea, nausea, and stomach cramps, and could increase the risk of kidney stones in some individuals.

Scientific findings confirm there is no need for high-dose vitamin C supplements to prevent colds; for most people, a balanced diet rich in fruits and vegetables is sufficient.

Anyone considering high doses should consult a doctor, especially those with chronic illnesses or who take regular medication.