Introduction
In today’s time, people are slowly getting aware of their health and fitness. After this coronavirus spread, people started to opt for more organic forms of living. They have realized the importance of being physically and mentally well and healthy. It’s very vital to get the proper amounts of nutrients and vitamins and fiber in the body. We have to ensure that we all are having a balanced diet.
Having food at the correct point in time is also very necessary. If we have food at the incorrect or the wrong time, then it leads to a lot many health problems such as weight gain, obesity, headache, body weakness or sleepiness, slight mood swings, and so on. Vitamins A and C are actually very vital for maintaining a healthy body and mind. So today, we’ll dive into the key differentiating points of the two vitamins and understand a lot more about them.
Vitamin A vs Vitamin C
Vitamin A is basically a non-liquid soluble component that is required for the good health of the human body. Vitamin C, on the other hand, is actually a liquid soluble component. Vitamin C is a water-soluble component that is required by the human body. Both can be found in a variety of products and foods.
Difference Between Vitamin A and Vitamin C in Tabular Form
| Parameters of Comparison | Vitamin A | Vitamin C |
| Content | Vitamin A is found in green foods such as vegetables and leafy greens. | Tomatoes, broccoli, and citrus fruits are high in vitamin C. |
| Benefits | Because of their high antioxidant content, vitamin A foods are beneficial to the skin and eyes. | Meals high in vitamin C are necessary for bone growth, wound healing, and infection prevention. |
| Blood Absorption | Vitamin A basically cannot be taken into the bloodstream unless lipids are actually present. | Without the use of lipids, the vitamin C is actually absorbed directly into the bloodstream. |
| The collagen content | Collagen is not produced by vitamin A in their foods. | Collagen is produced by vitamin C in their diets. |
| Their main use | Vitamin A is primarily considered when the body is deficient. | Vitamin C is mostly used to treat deficiencies in the skin (Difference Between Vitamin A and Vitamin C (With Table), n.d.) |
What is Vitamin A?
Vitamin A is basically a fat-soluble vitamin that is necessary for human health. Retinol, retinal (also known as retinaldehyde), retinoic acid, and numerous provitamin A carotenoids (most notably beta-carotene [-carotene]) make up this category of chemical substances. Vitamin A is required for embryonic development and growth, immune system maintenance, and vision, where it interacts with the protein opsin to generate rhodopsin, the light-absorbing molecule required for both low-light (scotopic vision) and color vision.
In meals, there are two types of vitamin A: A) the carotenoids alpha-carotene, -carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain -ionone rings) that function as provitamin A in herbivore and omnivore animals that possess the enzymes that cleave and convert provitamin carotenoids to retinal and then to retinol, which are found in. This enzyme is absent in some carnivore species. The other carotenoids don't have any vitamin-like properties.
Passive diffusion allows dietary retinol to be absorbed from the digestive tract. Unlike retinol, -carotene is transported through the membrane transporter protein scavenger receptor B1 (SCARB1), which is increased during vitamin A insufficiency. Retinol is stored in lipid droplets in the liver. Because of retinol's tremendous potential for long-term storage, well-nourished humans can go months without vitamin A or beta-carotene while maintaining normal blood levels. Signs and symptoms of deficiency appear only after the liver resources are virtually depleted. Retinol is transformed to retinal, which is reversible and then to retinoic acid, which is irreversible and activates hundreds of genes.
Dietary intake recommendations and upper limits for safe intake have been established by the European Union and other countries. Vitamin A toxicity, also known as hypervitaminosis A, occurs when the body accumulates too much vitamin A. Nervous system effects, liver abnormalities, weariness, muscle weakness, bone, and skin alterations, and other symptoms may occur. When high-dose supplements are removed, the negative effects of acute and chronic toxicity are reversed.
Absorption, the Metabolism, and the Excretion
- Retinyl esters from animal-sourced meals (or produced for human and domesticated animal dietary supplements) are actually hydrolyzed by retinyl ester hydrolases in the small intestine lumen to liberate free retinol. Passive diffusion then basically allows retinol to penetrate intestine absorptive cells. Actually, The absorption efficiency ranges from 70-to 90%. Now because there are no mechanisms that can limit absorption or eliminate excess vitamin A in urine, humans are at risk for acute or chronic vitamin A toxicity. Retinol is linked to retinol-binding protein 2 within the cell (RBP2). It is then esterified enzymatically by lecithin retinol acyltransferase and integrated into chylomicrons before being secreted into the lymphatic system.
- Unlike retinol, -carotene is taken up by enterocytes via the scavenger receptor B1 membrane transporter protein (SCARB1). When there is a vitamin A deficiency, the protein is increased. SCARB1 is downregulated when vitamin A levels are normal, which reduces absorption. The enzyme beta-carotene 15,15'-monooxygenase, which is called for by the BCMO1 gene and is responsible for symmetrically cleaving -carotene into retinal, is also downregulated. Absorbed -carotene is either directly absorbed into chylomicrons or transformed to retinal and subsequently retinol before being linked to RBP2. After a meal, the liver absorbs around two-thirds of the chylomicrons, while the rest is transported to peripheral tissues. Tissues in the periphery can also convert chylomicron-carotene to retinol.
- It’s known by experts that because of the ability of the liver to retain retinol, actually, the well-nourished people can go months without showing signs or symptoms of vitamin A insufficiency. Hepatocytes and hepatic stellate cells are the two types of liver cells responsible for storage and the release (HSCs). Hepatocytes absorb lipid-rich chylomicrons, then bind retinol to retinol-binding protein 4 (RBP4), and after that they transmit the retinol-RBP4 to HSCs, where it is actually stored as retinyl esters in lipid droplets. Retinyl ester hydrolase releases free retinol, which is transported to hepatocytes, bound to RBP4, and circulated in the bloodstream during mobilization. More than 95% of retinol in the circulation is bound to RBP4 except when consumption of large amounts exceeds the liver storage capacity.
Aside from vision, all-trans-retinoic acid is responsible for vitamin A's metabolic actions (RA). It is impossible to reverse the development of RA from the retinal. To prevent the accumulation of RA, it is promptly oxidized and removed, resulting in a short half-life. The oxidation of retinoic acid is catalysed by three cytochromes. High levels of RA stimulate the genes for Cyp26A1, Cyp26B1, and Cyp26C1, creating a self-regulating feedback loop.
The state of vitamin A affects eye health in two ways. The retina's rod cells and cone cells respond to light exposure by delivering nerve signals to the brain, and the retina is an important part of this process. Night blindness is an early indication of vitamin A insufficiency. Retinoic acid, a type of vitamin A, is required for optimal epithelial cell function. Xerophthalmia is a dryness of the conjunctival epithelium and cornea caused by severe vitamin A insufficiency, which is frequent in new-borns and young children in Southeast Asia. Xerophthalmia leads to corneal ulcers and blindness if left untreated.
Role of Vitamin A in the Visual Cycle
Vitamin A's role in the visual cycle is basically very closely linked to the retinal molecule. Within the retinal pigment epithelium, the enzyme RPE65 converts the retinol to 11-cis-retinal. Then, Within the eye, 11-cis-retinal binds to the protein opsin in order to generate rhodopsin in rod cells and iodopsin in cone cells, resulting in rhodopsin in rod cells and iodopsin in cone cells. Next, the 11-cis-retinal is isomerized to the all-trans form as light enters the eye. In a process known as photo-bleaching, the all-trans retinal separates from the opsin. This isomerization sends a neurological signal to the brain's vision center via the optic nerve. The all-trans retinal is recycled and transformed back to the 11-cis retinal form by a sequence of enzyme processes after being separated from opsin, and the cycle is completed by binding to opsin (Vitamin A, n.d.).
What is Vitamin C?
So basically, Vitamin C (also known as ascorbic acid or ascorbate) is a water-soluble vitamin that can be found in citrus fruits and vegetables and is even available as a dietary supplement. It is actually utilized to prevent and treat scurvy. Vitamin C is actually a necessary nutrient for tissue healing, collagen creation, and the enzymatic manufacture of some neurotransmitters. It is vital for immune system function and is required for the operation of numerous enzymes. It also has anti-oxidant properties.
Vitamin C is well tolerated by the majority of people. High dosages might cause stomach discomfort, headaches, insomnia, and skin flushing. Normal doses are safe to use while pregnant. The Institute of Medicine of the United States of America advises against taking high amounts.
Vitamin C is actually an important nutrient for humans and other animals. Vitamin C refers to a group of vitamins that have vitamin C activity in animals. Also, some dietary supplements contain ascorbate salts such as sodium ascorbate and calcium ascorbate. Hence, when these are digested, they release ascorbate. Now because the forms interconvert according to pH, both ascorbate and ascorbic acid are naturally present in the body. Reducing agents convert oxidized versions of the molecule, such as dehydroascorbic acid, back to ascorbic acid.
Deficiency of Vitamin C
Scurvy is an illness caused by a vitamin C deficiency. Collagen produced by the body is too unstable to execute its role without this vitamin, and various other enzymes in the body malfunction. Spots on the skin and under the skin, spongy gums, 'corkscrew' hair growth, and poor wound healing are all symptoms of scurvy. The skin lesions are more common on the thighs and legs, and the patient appears pale, dejected, and partially immobile. Open, suppurating wounds, tooth loss, bone deformities, and mortality are all symptoms of advanced scurvy.
During World War II in Britain, notable human nutritional studies of deliberately produced scurvy were undertaken on conscientious objectors, and in the late 1960s and 1980s, on Iowa state prisoners. The males in the jail research developed scurvy symptoms four weeks after commencing the vitamin C-free diet, whereas the men in the earlier British study took six to eight months, presumably because this group was given a 70 mg/day supplement for six weeks before the scorbutic diet was given. By the time the men in both groups experienced symptoms of scurvy, their blood levels of ascorbic acid were too low to be adequately quantified. Both of these studies found that supplementation could completely reverse all of the symptoms of scurvy.
Vitamin C plays a critical role in the treatment of scurvy, a disease characterized by a lack of vitamin C. Beyond that, the usefulness of vitamin C in illness prevention or treatment is debatable, with studies yielding contradictory results. Vitamin C supplementation had no influence on overall mortality, according to a Cochrane analysis published in 2012 (Vitamin C, n.d.).
Main Differences Between Vitamin A and Vitamin C In Points
Now, let’s get to know the major points of differences between Vitamin A and Vitamin C in the following points:
- Vitamin A is a type of vitamin that helps to prevent infections of the eyes. It aids in the restoration of sight and helps to improve the proper functioning of the visual system by giving nutrients to the eyes.
- Vitamin C is a vitamin that is used to prevent the onset of certain ailments. It aids in the proper functioning of the immune system by assisting in the battle against infections and other disorders within the body.
- Vitamin A is basically found in a variety of foods, and some are also available in tablet form.
- Many foods naturally contain vitamin C, and some are available inorganically.
- Vitamin A is actually a fat-soluble vitamin, which means it is stored in your body's fat cells, but it must be replenished on a regular basis.
- Vitamin C, on the other hand, is a water-soluble vitamin, meaning it dissolves in water. Except for vitamin B12, our body only retains water-soluble vitamins for a few weeks to months before excreting them through our urine. Hence, we should take water-soluble vitamins on a regular basis (Vitamins A, C and E, n.d.).
Conclusion
After knowing all these differentiating points between Vitamin, A and Vitamin C, we have come to know their importance for our overall health. We also came across some interesting and new facts about these two vitamins that further added to our knowledge. Therefore, to conclude, we can say that it’s very essential to maintain a healthy balance of these two vitamins in our body.
References
- Vitamin A. (n.d.). Retrieved from WIKIPEDIA: https://en.wikipedia.org/wiki/Vitamin_A
- Vitamin C. (n.d.). Retrieved from WIKIPEDIA: https://en.wikipedia.org/wiki/Vitamin_C
- Vitamins A, C and E. (n.d.). Retrieved from VERSUS ARTHRITIS: https://www.versusarthritis.org/about-arthritis/complementary-and-alternative-treatments/types-of-complementary-treatments/vitamins-a-c-and-e/
