Vitamin C or L-ascorbic acid, or simply ascorbate, is an essential nutrient for humans and certain other animal species. Vitamin C refers to a number of vitamers that have vitamin C activity in animals, including ascorbic acid and its salts, and some oxidized forms of the molecule like dehydroascorbic acid. Ascorbate and ascorbic acid are both naturally present in the body when either of these is introduced into cells, since the forms interconvert according to pH.
Vitamin C is a cofactor in at least eight enzymatic reactions, including several collagen synthesis reactions that, when dysfunctional, cause the most severe symptoms of scurvy. In animals, these reactions are especially important in wound-healing and in preventing bleeding from capillaries. Ascorbate may also act as an antioxidant against oxidative stress. However, the fact that the enantiomer D-ascorbate (not found in nature) has identical antioxidant activity to L-ascorbate, yet far less vitamin activity, underscores the fact that most of the function of L-ascorbate as a vitamin relies not on its antioxidant properties, but upon enzymic reactions that are stereospecific. "Ascorbate" without the letter for the enantiomeric form is always presumed to be the chemical L-ascorbate.
Ascorbate (the anion of ascorbic acid) is required for a range of essential metabolic reactions in all animals and plants. It is made internally by almost all organisms; the main exceptions are bats, guinea pigs, capybaras, and the Anthropoidea (i.e., Haplorrhini, one of the two major primate suborders, consisting of tarsiers, monkeys, and humans and other apes). Ascorbate is also not synthesized by some species of birds and fish. All species that do not synthesize ascorbate require it in the diet. Deficiency in this vitamin causes the disease scurvy in humans.Ascorbic acid is also widely used as a food additive, to prevent oxidation.
Vitamin C is a water-soluble vitamin that is necessary for normal growth and development. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.Function
Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to:
Form an important protein used to make skin, tendons, ligaments, and blood vesselsHeal wounds and form scar tissue
Repair and maintain cartilage, bones, and teeth.
Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals.
Free radicals are made when your body breaks down food or when you are exposed to tobacco smoke or radiation.
The buildup of free radicals over time is largely responsible for the aging process.
Free radicals may play a role in cancer, heart disease, and conditions like arthritis.
The body is not able to make vitamin C on its own, and it does not store vitamin C. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.
For many years, vitamin C has been a popular remedy for the common cold.
Research shows that for most people, vitamin C supplements or vitamin C-rich foods do not reduce the risk of getting the common cold.
However, people who take vitamin C supplements regularly might have slightly shorter colds or somewhat milder symptoms.
Taking a vitamin C supplement after a cold starts does not appear to be helpful.Food Source
All fruits and vegetables contain some amount of vitamin C. Fruits with the highest sources of vitamin C include:
Cantaloupe, Citrus fruits and juices, such as orange and grapefruit, Kiwi fruit, Mango, Papaya, Pineapple, Strawberries, raspberries, blueberries, cranberries, Watermelon.
Vegetables with the highest sources of vitamin C include:Broccoli, Brussels sprouts, cauliflower, Green and red peppers, Spinach, cabbage, turnip greens, and other leafy greens, Sweet and white potatoes, Tomatoes and tomato juice, Winter squash.
Some cereals and other foods and beverages are fortified with vitamin C. Fortified means a vitamin or mineral has been added to the food. Check the product labels to see how much vitamin C is in the product.
Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving and steaming vitamin C-rich foods may reduce cooking losses. The best food sources of vitamin C are uncooked or raw fruits and vegetables.Side Effects
Serious side effects from too much vitamin C are very rare, because the body cannot store the vitamin. However, amounts greater than 2,000 mg/day are not recommended because such high doses can lead to stomach upset and diarrhea.
Too little vitamin C can lead to signs and symptoms of deficiency, including:Anemia, Bleeding gums, Decreased ability to fight infection, Decreased wound-healing rateDry and splitting hair, Easy bruising, Gingivitis (inflammation of the gums), NosebleedsPossible weight gain because of slowed metabolism, Rough, dry, scaly skin, Swollen and painful joints, Weakened tooth enamel.
A severe form of vitamin C deficiency is known as scurvy, which mainly affects older, malnourished adults.Recommendations
The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important.
The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods.
Dietary Reference Intakes for vitamin C:Infants0 - 6 months: 40* milligrams/day (mg/day)7 - 12 months: 50* mg/day*Adequate Intake (AI)
Children1 - 3 years: 15 mg/day4 - 8 years: 25 mg/day9 - 13 years: 45 mg/day
AdolescentsGirls 14 - 18 years: 65 mg/dayBoys 14 - 18 years: 75 mg/day
AdultsMen age 19 and older: 90 mg/dayWomen age 19 year and older: 75 mg/day
Smokers or those who are around secondhand smoke at any age should increase their daily amount of vitamin C an additional 35 mg per day.
Women who are pregnant or breastfeeding and those who smoke need higher amounts of vitamin C. Ask your doctor what amount is best for you.
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