Vitamin C to prevent and treat the cold: myth or reality?

During the winter months, absenteeism or decreased productivity at work or school are often attributed to the symptoms of the common cold.

Many people search for products without a prescription for their symptoms, and some of the commonly purchased products are those with high doses of vitamin C supplements. But are they necessary and recommended? Is it true that vitamin C prevents and treats the cold?

The purpose of a current review has been to review current data on the relationship between vitamin C and immune function, specifically the usefulness of vitamin C supplementation in the prevention and treatment of the common cold.

Great antioxidant and protective against oxidative stress

Vitamin C is a potent water-soluble antioxidant that gives the immune system a boost through increased T-cell activity, phagocyte function, mobility of leukocytes and the possible production of antibodies and interferons.

The latter (interferons) are a group of signaling proteins produced and secreted by the host cells in response to the presence of various pathogens, such as viruses, bacteria , parasites and tumor cells .

In turn, the effects of vitamin C on the immune system can also be potentially explained by protecting against oxidative stress generated during infections.

Essential dietary component

The vitamin C is not produced endogenously in humans and is therefore one essential dietary component.

It has been indicated that vitamin C is safe when used below 2000 milligrams a day, and can be consumed through dietary sources, such as fresh fruits and vegetables, especially citrus, but there is conflicting evidence about the benefit of additional supplementation of vitamin C for the prevention and treatment of the common cold.

Not so much to prevent the cold, but more to reduce its duration and severity

The results of a systematic review in 2013 indicated that for the general population, vitamin C supplementation administered at doses ≥ 0.2 grams / day had no effect on the number of people who contract the common cold.

Interestingly, a subgroup analysis found that regular vitamin C supplementation in people with high physical stress ( marathon runners, skiers and soldiers) did decrease the incidence of the common cold by 50%.

Although regular administration of vitamin C did not seem to affect the incidence of the common cold in the general population, the review also analyzed the effect of regular vitamin C supplementation on the duration of symptoms and the severity of colds.

The results indicated that regular vitamin C supplements (at an average dose of 1-2 grams / day ) resulted in a significant reduction in the duration of common colds, an 8% reduction for adults and a 14% reduction for adults. children . In turn, the severity of cold symptoms was also reduced.

Better to get vitamin C from food than to supplement

A recent review of the year 2016 has reported on all aspects to know on the subject of vitamin C and cold.

Although there is a definite physiological effect of regular vitamin C supplementation on the duration and severity of the common cold, the practical importance of these findings is not very convincing.

It does not seem reasonable to ingest additional vitamin C outside of the food intake throughout the year if the only benefit is the potential of a slightly shortened duration of the cold and diminished symptoms.

Although the data do not consistently support the use of therapeutic vitamin C (most often the answer in a “no”), supplementation with vitamin C is used as an additional precaution when a person feels a cold comes, and this is the which is why many popular over – the – counter products are marketed.

The National Institutes of Health recommends daily intake of 90 milligrams of vitamin C for men and 75 milligrams for women with a focus on obtaining those amounts of dietary sources, especially fruits and vegetables , with citrus being a great source of vitamin C.

These organisms suggest that consuming five varied servings of fruits and vegetables a day can provide more than 200 milligrams of vitamin C, so, seeing the recommended daily intakes, supplementation with vitamin C is totally unnecessary.

Supplementation may be necessary for those specific patients with a marginal vitamin C status, such as the elderly and chronic smokers, but the majority of the population should focus on getting vitamin C from their diet.

Key points with which we have to stay

• Although the data show a decrease in the severity and duration of colds when vitamin C is consumed at doses equal to or greater than 0.2 g / day, it is more reasonable for patients to obtain this from their diet , considering that the Supplementation does not decrease the overall incidence of colds in the general population.
• Regular supplementation may have a place in special populations , specifically those with high physical stress and those with a marginal vitamin C status.
• In general, although there is a wide variety of data available, there is a lack of consistency, and more studies are needed to provide clarity on the usefulness of vitamin C for therapeutic purposes.
• Given the low cost and relative safety of vitamin C supplementation, it is not unreasonable for patients with cold symptoms to see for themselves if the therapeutic vitamin C is beneficial, but they should know that the data behind its use are largely inconsistent measurement.
• It seems that the greatest potential for the benefit of vitamin C in the treatment of the common cold occurs when the administration of the supplement begins within 24 hours of the onset of symptoms at high doses (about eight grams / day) and when the therapy It is continued for at least five days.