Do you know the benefits of vitamin C?
Vitamin C, also known as ascorbic acid, is an essential nutrient in our diet. Most animals are capable of synthesizing it endogenously from glucose metabolism by the action of the enzyme L-gluconolactone oxidase, but over time, humans have lost the ability to synthesize it due to mutations in the gene. encoding said key enzyme in the biosynthetic pathway. (1) It is practically not stored in the body and for this reason it is necessary to ingest it daily. It is present in certain foods such as citrus fruits (oranges, grapefruit, tangerines, etc.), red fruits (strawberries, blackberries, etc.) and certain vegetables (tomatoes, peppers, broccoli and spinach). The recommended daily amount to cover the minimum needs is 80 mg/day for healthy adults
Vitamin C is a water-soluble vitamin involved as a cofactor in at least 300 biochemical reactions in the body and its deficiency due to inadequate intake is associated with a large number of symptoms (anaemia, poor healing, fatigue, depression, bleeding gums, etc.). All these symptoms are typical of scurvy, a disease caused by severe vitamin C deficiency. Historically, it was associated with sailors who spent long periods at sea where the crew did not have access to fruits, vegetables and other foods. At present it is a rare condition, but it can manifest itself in people of advanced age or who suffer from malnutrition. (2) It is mainly characterized by the weakening of collagen structures, which leads to poor wound healing and impaired immunity. If not treated in time, people with severe vitamin C deficiency can suffer serious respiratory diseases such as pneumonia. (3). Fatigue and weakness due to a lack of vitamin C is due to insufficient production of L-carnitine, whose main function is to help the body in the process of oxidizing fats to obtain energy. On the other hand, vitamin C acts as a co-substrate of dopamine-β-monooxygenase, a key enzyme for the conversion of dopamine into norepinephrine. When vitamin C levels are low, the conversion of these neurotransmitters is deficient and can contribute to the appearance of depression, affecting mood in general. (4) These feelings of fatigue and emotional discomfort can manifest as a reduced desire to be physically active. (5)
On the other hand, although taking oral vitamin C supplements does not prevent you from catching a cold, there are some scientific studies that show that supplementation can help reduce the duration and severity of the cold. (6) For this, you have to start taking them before you catch a cold, as a preventative, and not as a treatment. (7) The reduction in the duration of a common cold has been related to the improvement of the immune system (8) while the reduction in the severity of the disease could be explained by the antihistamine property of vitamin C. (9)
As we have mentioned, vitamin C is involved as a cofactor in a multitude of metabolic processes, but among its numerous benefits we can highlight its regulatory action on the immune system and its powerful activity as an antioxidant, protecting cells against oxidative damage. Vitamin C supports the epithelial barrier and protects us against pathogens and free radicals present in the environment (tobacco smoke, pollution and ultraviolet radiation). Free radicals are harmful to our health: they cause aging, DNA mutations and could influence the appearance of cardiovascular diseases, arteriosclerosis, diabetes and cancer. (10) People with gastrointestinal conditions and some cancers may be more prone to vitamin C deficiency. This vitamin is also used to increase iron absorption from the gastrointestinal tract. (11) At present, therapy with high doses of vitamin C is very commonly used among naturopathic physicians and integrative medicine oncology professionals as a way of inducing cytotoxicity in tumour cells. (12) Although additional studies are still needed to clarify its mechanism of action, the most common hypothesis refers to its excellent redox properties, its ability to inhibit angiogenesis and its contribution to the maintenance of the immune system. (13)
In relation to its participation in the normal functioning of the immune system, it should be said that vitamin C accumulates in high concentrations in phagocytic cells, such as neutrophils, improving chemotaxis, phagocytosis and the reduction of reactive oxygen species (ROS). In addition, it is necessary for apoptosis and the elimination of microbes at local sites of infection, thus reducing necrosis and cell damage. The role of vitamin C in lymphocytes is less clear, but it has been shown to work by improving the differentiation and proliferation of B and T cells, responsible for recognizing pathogens, possibly due to its gene regulation effects. In short, vitamin C deficiency results in impaired immunity and increased susceptibility to infections. Oral vitamin C supplementation might be able to prevent and treat respiratory and systemic infections. Administered in high doses (grams) it could compensate for the increased inflammatory response and metabolic demand in the case of pulmonary infections. (14)
Vitamin C also acts as a cofactor for the enzymes lysine hydroxylase and proline hydroxylase, essential enzymes for the normal formation of collagen in the different tissues of our body such as skin, blood vessels, bones, mucous membranes, cartilage and teeth. The role of vitamin C is to maintain iron in its ferrous state (Fe+2) present at the catalytic site of these enzymes. The function of 4-hydroxyproline and 5-hydroxylysine is to stabilize and consolidate the triple helix of collagen through hydrogen bonds. (15)
Vitamin C is a highly unstable nutrient that is easily broken down by light and heat, for example when cooking food, so it is not always possible to be sure how much we are getting through our diet. For this reason, supplements are an effective alternative in those cases where we need a greater requirement of this vitamin. The question we now ask is what type of plugin to choose. Due to its acidity, vitamin C can cause slight gastric discomfort in people with very sensitive stomachs and since it is metabolized very quickly, the best choice would be to choose a vitamin C supplement that has a gastro-resistant coating. In this way, possible stomach discomfort could be avoided and bioavailability increased, since it is absorbed directly in the small intestine. On the other hand, if what we are looking for is a vitamin C-based supplement of natural origin, rose hip (Rose Hip, in English) is the best option. In addition to being one of the richest vegetable sources of vitamin C, it contains bioflavonoids that improve the absorption and bioavailability of this vitamin. Normally, rose hip-based supplements are enhanced with a standardized amount of vitamin C in the form of ascorbic acid, thus offering a natural and powerful mixture to enjoy the benefits that vitamin C brings to our health.
- Nishikimi, M. et al. Cloning and chromosomal mapping of the human nonfunctional gene for L-gulono-gamma-lactone oxidase, the enzyme for L-ascorbic acid biosynthesis missing in man. J. Biol. Chem. 1994, 269, 13685–13688.
- Olmedo J.M, et al. Scurvy: a disease almost forgotten. Inter J Dermatol, 2006; 45: 909-13.
- Hemila, H. Vitamin C and Infections. Nutrients 2017, 9, 339.
- Carr, A.C. et al. The role of vitamin C in the treatment of pain: New insights. J. Transl. Med. 2017, 15, 77.
- Carol S. Johnston et al. Vitamin C Supplementation Slightly Improves Physical Activity Levels and Reduces Cold Incidence in Men with Marginal Vitamin C Status: A Randomized Controlled Trial. Nutrients 2014, 6, 2572-2583.
- Hemilä, H. Vitamin C intake and susceptibility to the common cold. Br. J. Nutr. 1997, 77, 59–72.
- Hemilä, H.; Chalker, E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst. Rev.; 2013, 1, CD000980.
- Wintergerst, E.S. et al. Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Ann. Nutr. Metab.; 2006, 50, 85–94.
- Uchida, K.; Mitsui, M.; Kawakishi, S. Monooxygenation of N-acetylhistamine mediated by L-ascorbate. Biochim. Biophys. Acta; 1989, 99, 377–379.
- Bjelakovic G. et al. Antioxidant supplements and mortality. Curr Opin Clin Nutr Metab Care, 2014; 17:40–44.
- Lane D.J et al. The Active Role of Vitamin C in Mammalian Iron Metabolism: Much More Than Just Enhanced Iron Absorption!, Free Radic Biol Med. 2014; 75:69-83.
- Heidi Fritz et al. Intravenous Vitamin C and Cancer: A Systematic Review, Integrative Cancer Therapies, 2014, Vol. 13(4) 280–300.
- Abel Ang et al. Vitamin C and immune cell function in inflammation and cancer, Biochemical Society Transactions, 2018; 46, 1147–1159.
- Anitra C. Carr. et al. Vitamin C and Immune Function. Nutrients; 2017, 9, 1211.
- Kelly L. G. and Ronald T. R. Prolyl 4-hydroxylase. Crit Rev Biochem Mol Biol. 2010; 45(2): 106–124.