What Is Vitamin C?
Vitamin C, or ascorbic acid, is a naturally found organic compound with antioxidant characteristics. It is present in both animals and plants. It functions as a redox buffer; that is, it can reduce and neutralize reactive oxygen species or free radicals. It acts as a cofactor for enzymes that regulate photosynthesis and hormone biosynthesis and regenerate other antioxidants. It also controls cell division and growth, participates in signal transduction, and is a part of many physiological processes, like immune system stimulation, collagen synthesis, synthesis of hormones and neurotransmitters, and iron absorption. It also detoxifies the body of heavy metals.
Severe deficiency of vitamin C leads to scurvy; however, restricted vitamin C intake causes symptoms like increased predisposition to infections, loosening of teeth, dryness of the mouth and eyes, loss of hair, dry and itchy skin, fatigue, and insomnia. In contrast, vitamin C can also function as a prooxidant, particularly in the presence of transition metals, like iron and copper, leading to various hazardous radical reactions. Vitamin C can behave both as a powerful, efficient, and cheap antioxidant and, at the same time, perform as a radical promoter. However, further studies are required to illuminate the dual roles of vitamin C.
What Is an Antioxidant and How Does It Act?
An antioxidant is any compound that can fight against unstable molecules called free radicals in the human body that damage DNA (deoxyribonucleic acid), cell membranes, and other parts of cells. As free radicals are devoid of a full complement of electrons, they steal electrons from other molecules and damage them in the process. Antioxidants neutralize free radicals by lending some of their electrons to them. In this activity, they serve as a natural "off" switch for the reactive oxygen species. This helps break a chain reaction that can damage other molecules in the cell and other body cells. But what is important here is that "antioxidant" reflects a chemical property rather than a certain nutritional characteristic.
What Are Free Radicals and What Are Their Roles in the Human Body?
Though free radicals are harmful yet, they are an inevitable part of life. The human body produces free radicals in response to environmental insults, like tobacco smoke, ultraviolet rays, and air pollution, and also as a natural byproduct of cell physiological processes. For example, when the immune system functions to fight pathogens, oxygen is utilized, which kills viruses, bacteria, and damaged body cells in an oxidative burst. However, some free radicals are also produced naturally during exercise. This is important to induce certain beneficial effects of regular physical activity, like sensitizing the muscle cells to insulin.
Because free radicals are so common, a person requires an optimal supply of antioxidants to destroy them. Our body's cells naturally generate strong antioxidants, like alpha lipoic acid and glutathione. However, the foods we consume provide other antioxidants, like vitamins C and E. Plants are packed with compounds called phytochemicals; many also seem to carry antioxidant characteristics. For instance, after vitamin C has suppressed a free radical by lending electrons to it, a phytochemical known as hesperetin (present in oranges and other citrus fruits) restores vitamin C to its active antioxidant form. In addition, carotenoids (like lycopene in tomatoes and lutein in kale) and flavonoids (like flavanols in cocoa, anthocyanins in blueberries, quercetin in apples and onions, and catechins in green tea) are also antioxidants.
What Are the Sources and Other Functions of Vitamin C?
Vitamin C (ascorbic acid) is a nutrient our body needs to form blood vessels, cartilage, muscle, and collagen in bones. Vitamin C is also essential for our body's healing process. In addition, vitamin C is an antioxidant that helps protect the cells of our body against the effects of free radicals. Free radicals also play a role in heart disease, cancer, and other diseases.
As our body does not produce and store vitamin C, we need to get it from our diet regularly. Vitamin C is present in citrus fruits, berries, potatoes, tomatoes, peppers, Brussels sprouts, broccoli, cabbage, and spinach. Vitamin C can also be taken as an oral supplement, typically as capsules and chewable tablets. However, most people get sufficient vitamin C from a healthy diet. Vitamin C deficiency occurs most commonly in the following people:
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Those who smoke or are exposed to secondhand smoke.
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Those who have some gastrointestinal conditions or some types of cancer.
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Those who follow a restricted diet that does not regularly contain fruits and vegetables.
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Severe vitamin C deficiency can cause scurvy, leading to anemia, bleeding gums, bruising, and poor wound healing.
If a person depends on vitamin C supplements for their benefits, particularly the antioxidant property, note that the supplement might not render the exact profits as naturally present antioxidants in food. The recommended dietary allowance (RDA) of vitamin C is 90 mg (milligram) for adult men and 75 mg for adult women.
What Are the Effects of Vitamin C on Various Health Conditions?
Much research has been done on vitamin C for certain diseases or conditions. The information is as follows:
1. Cancer: Consuming a diet packed with fruits and vegetables might decrease the risk of several types of cancer, like breast, colon, and lung cancers. However, whether this protective effect is linked to vitamin C in the food is not distinct, as oral vitamin C supplements do not appear to provide similar profit.
2. Common Cold: Consuming oral vitamin C supplements does not prevent the common cold. The results of the studies also show that the benefits of regularly having vitamin C supplements to decrease the duration or severity of a cold are the least.
3. Eye Diseases: Oral vitamin C supplements and other vitamins and minerals prevent age-related macular degeneration (AMD) from worsening. Certain studies also suggest that people with increased levels of vitamin C in their diets have a decreased chance of developing cataracts.
Conclusion:
Vitamin C acts as a powerful antioxidant and helps in fighting against free radicals, which otherwise lead to many chronic and life-threatening diseases and conditions. However, it is more important to fulfill its requirement through the daily diet instead of depending on supplements.
