Vitamin C is a water-soluble vitamin, which does not need to be consumed with fatty food in order to be absorbed. It is known for its role in supporting the immune system. Each time we get cold we take in supplements or we just increase our vegetable or fruit intake so we can provide our organism with this powerful antioxidant. Not only does vitamin C strengthens the immune system, but it also is an irreplaceable factor for the production of collagen, takes part in the electron transport chain. Actually, one can easily fulfill the daily requirements, as many fruits and veggies are really rich in vitamin C. The main focus of this article is going to be the connection between collagen and vitamin C. Another thing that should be taken into consideration is the link between vitamin c and pregnancy.
Formation of collagen
Collagen is the most abundant protein in the organism and it is a part of the structure of the skin, bones, tendons, nails, lenses, etc. There are 28 types of collagen but the most common are type I and type IV. Type I comprises over 90% of the collagen in the body. Collagen has a steady structure and tight configuration, which is due to the fact that every third residue in each chain of the triple helix is glycin. The production of collagen happens in the so-called fibroblasts, which are specialized in synthesizing collagen. The process goes through intra- and extracellular phases. The formed pro-collagen, then, undergoes post-translational modification with the inclusion of vitamin C. On one hand, there are genetic reasons for the improper production of collagen. On the other hand, there are nutritional, which one could effortlessly take into consideration. In the structure of collagen there lysine and proline which undergo post-translational modification. From a molecular point of view, vitamin C is a cofactor of enzyme, called lysyl- and prolylhydroxylase, which insert –OH groups in the lysine and proline residues. This process enables the pro-collagen to become collagen, which is a more stable form. Lack of vitamin C in the diet can cause improper or insufficient collagen production and, thus could lead to bone fragility, bleeding gums, slow wound healing. Vitamin C deficiency could also lead to scurvy. This is not a genetic disease and it is characterized with weakness, muscle soreness, decreased amount of red blood cells, gum weakening and therefore falling teeth. Scurvy has been very common among sailors during prolonged voyages. It has happened due to malnutrition. Nowadays, scurvy is rarely diagnosed but when it happens it is usually observed among the populations of developing countries or refugees, which do not have access to high-quality food. It takes at least a month of insufficient vitamin C intake in order for the symptoms to occur.
Preclinical and clinical studies on increased vitamin C intake
Results of preclinical studies, including animals, show that increased vitamin C intake of 1000 mg/d aids in the healing of muscle injuries. However, there is no significant change in clinical studies. On the contrary, low doses (60 mg/d) orally administred show a noticeable difference of increased bone biomarkers in comparison to control groups. So, preclinical studies show improved collagen-rich matrix, faster rates of chondrocyte development and hyperthrophy, neutralizing reactive oxygen species, higher tensile strength and stiffness from increased collagen cross-linking, reduced formation of scars, faster wound healing. What is common between the preclinical and clinical study is the increased bone density and bone healing from fractures.
Vitamin C and pregnancy
Naturally, during pregnancy the daily vitamin and mineral requirements increase and this counts for vitamin C, as well. Since vitamin C is very potent at destroying ROS- reactive oxygen, it is very important for the protection of the baby during the pregnancy and especially during the first 12 gestational weeks, when the embryo, then the fetus, is highly sensitive towards ROS, radioactive exposure and other environmental factors. This is the period, in which the placenta begins and ends its formation and since it has a lot of connective tissue, therefore collagen, vitamin C is crucial to the protection of the placenta. Oxidative stress can cause development of pre-eclampsia and pre-labour rupture of membranes (PROM), which is rupture of the membrane just before the labor at or beyond 37 weeks’ gestation. The symptoms are leakage of fluid, vaginal discharge, vaginal bleeding, and pelvic pressure without contractions. According to some empirical observations and assumptions, higher doses of vitamin C, beyond 2- or 3000 mg can lead to premature labor due to the decrease of the pH level in the organism. However, there is an insufficient amount of studies to prove it. Balance is everything, so one should keep in mind that “more” does not mean “healthier”.
Other functions of Vitamin C
Vitamin C is a really good reducer and it can reduce oxygen, nitrates, and cytochromes a and c, which are included in the electron transport chain. As a water-soluble antioxidant it can inhibit the formation of nitrosamines, which are carcinogenic. It takes part it in important oxidative reactions, such as catabolism of thyrosine, or anabolic reactions such as synthesis of noradrenaline, bile formation. It is also a very important factor for the steroidogenesis. It is proved that vitamin C increases the iron absorbption.
According to NIH- National Institutes of Health infants should consume at least 40 to 50 mg, mother milk contains vitamin C, so it is advisable that lactating women increase their intake. Children- around 40-50 mg, teens – 60 -75 mg; adult men- 90 mg, adult women- 75 mg, pregnant women- 85 mg, breastfeeding women- 120 mg.
Foods rich in Vitamin C:
One medium-sized orange contains around 80-90% of the daily requirements, one kiwi- 70%, 100 g of pomelo contain almost 100% of the RDI for vitamin C. Strawberries and raspberries score really high when it comes to vitamin C.Brussel sprouts, broccoli, bell peppers are rich in vitamin C.
One should always seek the golden mean. Not enough and too much of something can cause severe problems. Try getting enough vitamin C and do not overconsume it
Textbook: Medical biochemistry lectures- Medical university of Sofia.