Ascorbic acid is a fundamental substance for the survival of living beings. Its enormous importance is expressed in particular by the name with which it is best known: vitamin C. Indeed, a "vitamin" is an essential substance for our vital functions (without it life is not possible!) and that our body is not able to build itself, therefore it necessarily needs to take it through nutrition.
Vitamin C participates in a huge number of biochemical reactions inside the human body. In our cells and in the blood vitamin C is one of the main antioxidant molecule, as it inactivates free radicals and performs an anti-inflammatory action. It also optimizes iron absorption in the intestine and it is an essential cofactor for the production of collagen. Collagen is a protein that, in our body, gives structure to many tissues, including tendons, joints, teeth, skin and blood vessels: in few words, collagen "keeps our body together"! Therefore, the catastrophic consequences of the deficiency of vitamin C present in scurvy disease are not surprising. In scurvy affected people tissues weaken and eventually collapse and tear apart as a consequence of collagen absence. In 1747 the Scottish physician James Lind discovered that, in order to cure the sailors of the English fleet from this devastating disease, it was enough to introduce oranges and lemons into their diet!
According to the directives of the European Union, the daily recommended values (RNV) of vitamin C to be taken correspond to 80 mg of vitamin C (about the content of an orange). However, this value represents the amount necessary to not have a deficiency of vitamin C. In order to fully exploit the benefits of vitamin C in supporting our health, a higher dosage is advisable.
Foods containing vitamin C are citrus fruits, kiwis, peppers, berries, tomatoes, broccoli, Brussels sprouts and other leafy vegetables. However, it should be considered that vitamin C is a rather sensitive nutrient which is degraded both with cooking and with the industrial preservation and transformation of food. It is also inactivated by light: when we prepare an orange juice, we should drink it quickly to ensure to assimilate all the vitamin C contained. Furthermore, the body's ability to absorb vitamin C is reduced by the intake of alcohol, smoking, viral diseases, use of antibiotics and pollution (Chambial et al., Ind J Clin Biochem, 2013).
Vitamin C is a valuable ally against infections for its ability to boost the immune system and to participate to the production and differentiation of white blood cells (Carr & Maggini, Nutrients, 2017). Vitamin C can ease symptoms and shorten the duration of the common cold (Chambial et al., Ind J Clin Biochem, 2013). Other studies have also suggested that vitamin C helps to prevent and to mitigate the symptoms of viral respiratory infections (Gorton & Jarvis, JMPT, 1999). Noteworthy, a recent meta-analysis published in February 2020, has shown that a supplementation of vitamin C at dosages between 1 and 6 grams per day has significantly improved the conditions of patients with respiratory diseases (Hemilä & Chalker, J Intensive Care, 2020).
Recommended use: take 1 gram of vitamin C per day.