Home remedies for the flu are very varied. Those of us who comb gray hair remember warm milk with honey or an egg yolk, even with some punch. But there is one that survives the passage of time and we can consider the best known and accepted: a good dose of vitamin C.
Is there a scientifically based reason for turn to vitamin C as a remedy against the flu? No, there is not for direct symptoms. Although yes for the possible sequels.
Although some studies have shown some ability of vitamin C to prevent some of the symptoms of the flu, the reality is that they present design problems. In fact, when an exhaustive study has been carried out analyzing multiple attempts to determine if treatment with vitamin C really improves the symptoms of the flu, the results have been null or very modest and only with excessively high doses such as 1 gram daily. Far from what a glass of orange juice or a handful of strawberries contains, for example.
In fact, the latest studies on clinical studies –what we know in the scientific world as meta-analyses and systematic reviews– emphatically conclude that only vaccines produce preventive effects, while the effect of vitamin C is negligible or absent in terms of direct flu symptoms.
Vitamin C: a great soluble antioxidant
Our body has molecular antioxidants that can be classified as hydrosoluble or water solublesuch as vitamin C and glutathione, and fat-soluble or fat-soluble, such as coenzyme Q10 and vitamin E.
These antioxidants play an essential role: reduce the levels of free radicals from the metabolism of oxygen or nitrogensuch as superoxide or hydrogen peroxide, and other more reactive ones that strongly attack DNA, producing mutations, such as hydroxyl radical or peroxynitrite.
Water soluble antioxidants reduce oxidative damage by scavenging some of these free radicals. For his part, those soluble in fats block the oxidation of membranes preventing multiple effects on cell activity. They also prevent cell death by a mechanism known as ferroptosis.
Antioxidants need enzymes to recycle them
For an antioxidant to be useful in our cells, it needs enzymes that continually recycle it. So a cycle is created in which the active version of the antioxidant molecule is consumed over and over again by reacting against radicalsbut the antioxidant enzymes present in the cells recycle them so that they can react again.
This cycle is known as the oxidation-reduction cycle, since the antioxidant oxidizes and reduces the free radical, eliminating it. Therefore, so that antioxidant molecules can fulfill their function must have antioxidant enzymes in sufficient quantity and capacity as to be recycled endlessly.
Therefore, gorge yourself on Antioxidant supplements do not make much sense if what is not working in our body are the enzymes that keep these molecules active. And when the body is out of balance, as occurs in chronic metabolic diseases or aging, these antioxidant enzymes function relatively poorly or are almost absent.
Vitamin C could prevent long-term damage
We all know the symptoms of the flu: cough, runny nose, malaise, fever, and joint pain. Influenza viruses invade cells and trigger an immune system response that produces an inflammatory effect.l that generates fever and characteristic joint pain.
In all this inflammatory phenomenon, free oxygen radicals are generated that add even more damage to the direct damage produced by the virus itself. Increased production of free radicals during the flu generates a series of damage to cells and tissues that can aggravate degenerative processes and accelerate the accumulation of cellular waste.
These long-term damage could be behind the aftermath that has been associated with flu epidemics and that end up generating premature deaths even years later.
That’s why the use of antioxidants could be considered a preventive therapy for oxidative damage generated by the general inflammation produced by the viral infection of both flu and covid-19.
We could therefore consider that Vitamin C in the treatment of influenza is very useful to prevent oxidative damage that occurs due to the inflammatory effects derived from infection by the virus.. In a well-fed person it would not be very necessary. However, in cases of deficiency or in the elderly, prevention is better than cure.
In the end, a moderate excess of vitamin C prevents oxidative damage without side effects. And since it clears up quickly, any help is welcome even if it doesn’t reduce symptoms much.
*To read the original note, published in The Conversation, click here.
*By Guillermo López Lluch, professor in the area of Cellular Biology. Associate researcher at the Andalusian Center for Developmental Biology. Researcher in metabolism, aging and immune and antioxidant systems, Pablo de Olavide University
*The Conversation is an independent, nonprofit source of news, analysis, and commentary from academic experts.