Introduction
Ascorbic acid (vitamin C), also known as L-ascorbic acid, is a water-soluble vitamin that can be found in naturally occurring amounts in some foods, added to others, and obtained through the use of dietary supplements. Because humans, unlike the majority of other animals, are unable to generate vitamin C on their own, it is considered an essential dietary component [1].
[1,2] Vitamin C is essential for the manufacture of collagen, L-carnitine, and some neurotransmitters, and it is also involved in the metabolism of proteins. Collagen is an essential component of connective tissue, and it plays a critical role in the healing of wounds and other injuries. [3] Vitamin C is also a powerful physiological antioxidant, and it has been proven to stimulate the production of other antioxidants in the body, such as alpha-tocopherol (vitamin E). According to current research, vitamin C, by reducing the destructive effects of free radicals through its antioxidant activity, may be able to prevent or postpone the development of certain malignancies, cardiovascular disease, and other diseases in which oxidative stress is a contributing factor. The antioxidant action of vitamin C, in addition to its biosynthetic and antioxidant roles, has been shown to be significant in immunological function [4]. Vitamin C also has been shown to increase the absorption of nonheme iron [5, the form of iron found in plant-based meals]. Vitamin C deficiency leads to scurvy, which manifests itself as extreme weariness or lassitude, extensive connective tissue weakness, and capillary fragility [1,2,4,6-9].
There is at least one particular dose-dependent, active transporter that regulates the absorption of vitamin C from the gastrointestinal tract [4]. Vitamin C is accumulated by cells through the action of a second specialised transport protein. It has been discovered in vitro that oxidised vitamin C, also known as dehydroascorbic acid, enters cells by some facilitated glucose transporters and is then converted internally to ascorbic acid by the body. It is not known what the physiological significance of dehydroascorbic acid absorption is or how it contributes to the total vitamin C economy.
Vitamin C taken orally produces tissue and plasma concentrations that are closely controlled by the body. When vitamin C is consumed in modest amounts (30–180 mg/day), around 70–90 percent of the vitamin is absorbed. At doses greater than 1 g/day, however, absorption decreases to less than 50%, and the absorbed, unmetabolized ascorbic acid is eliminated in the urine [4]. Ascorbic acid doses of 1.25 g/day create mean peak plasma vitamin C concentrations of 135 micromol/L, which are almost two times greater than those produced by ingesting 200–300 mg/day ascorbic acid from vitamin C-rich foods [10]. Pharmaceutical pharmacokinetic simulation suggests that even high dosages of vitamin C (3 g per 4 hours) will result in peak plasma concentrations of just 220 micromol/L [10], according to the model.
The total amount of vitamin C in the body varies from 300 mg (when the patient is close to scurvy) to approximately 2 g [4]. Throughout the body, cells and tissues retain high quantities of vitamin C (millimolar concentrations), with the largest levels found in leukocytes (white blood cells), the eyes, and the glands of the adrenals, pituitary, and the brain. Extracellular fluids like as plasma, red blood cells, and saliva [4] contain relatively low quantities of vitamin C (micromolar values) compared to intracellular fluids.
Consumption Recommendations
[8] Dietary Reference Intakes (DRIs) for vitamin C and other nutrients have been developed by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM), part of the National Academies (formerly the National Academy of Sciences) and published by the Institute of Medicine (IOM) of the National Academies. The term "DRI" refers to a collection of reference values that are used to plan and assess the nutritional intakes of healthy persons on a regular basis. These values, which differ depending on one's age and gender [8], include the following:
It is commonly used to create nutritionally adequate diets for individuals. Recommended Dietary Allowance (RDA): An average daily consumption amount sufficient to meet the dietary requirements of virtually all (97 percent –98 percent) healthy persons.
It is assumed that intake at this level will guarantee nutritional adequacy; it is established when there is insufficient evidence to develop a recommended daily allowance (RDA).
In this definition, Estimated Average Requirement (EAR) refers to an average daily level of intake estimated to meet the requirements of 50% of healthy individuals; it is typically used for assessing the nutrient intakes of groups of people and for planning nutritionally adequate diets for them; however, it can also be used for assessing the nutrient intakes of individuals.
Tolerable Upper Consumption Level (UL): The maximum daily intake that is unlikely to result in adverse health effects is defined as follows:
The current recommended daily allowances (RDAs) for vitamin C are listed in Table 1 [8]. The recommended daily allowances (RDAs) for vitamin C are based on the vitamin's known physiological and antioxidant effects in white blood cells and are significantly higher than the amount required to protect against deficiency [4,8]. The FNB created an AI for vitamin C for infants between the ages of one and twelve months, which is equal to the mean intake of vitamin C in healthy, breastfed infants throughout that time period.
Table 1: Vitamin C Recommended Dietary Allowances (RDAs) [8] for Adults and Children
Age Male Female Pregnancy Lactation
- 0–6 months of age
- 40 mg* 40 mg* 40 mg*
- a period of 7–12 months
fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes fifty milligrammes
A period of one to three years
- 15 milligrammes 15 milligrammes
- 4–8 years 25 mg 25 mg 4–8 years
- 9–13 years of age
- 45 milligrammes 45 milligrammes
- 14–18 years of age
- 75 mg 65 mg 80 mg 115 mg 75 mg 65 mg 80 mg 115 mg
- a period of 19 years or more
- 90 mg 75 mg 85 mg 120 mg 90 mg 75 mg 85 mg 120 mg
- Tobacco users Individuals who smoke require 35 mg per day
- smokers consume more vitamin C than nonsmokers
- * Adequate Nutrition (AI)
Vitamin C can be obtained from a variety of sources.
Food
As shown in Table 2, fruits and vegetables are the most abundant sources of vitamin C (13). Among the most important sources of vitamin C in the American diet [8,] citrus fruits, tomatoes and tomato juice, and potatoes are among the most abundant. Among the other nutritious foods are red and green peppers, kiwifruit (see Table 2), broccoli (see Table 2), strawberries, Brussels sprouts, and cantaloupe (see Table 2). Although grains do not naturally contain vitamin C, it is added to some fortified breakfast cereals to make them more nutritious. Because ascorbic acid is water soluble and degraded by heat [6,8], it is possible for the vitamin C content of food to be lowered through lengthy storage and cooking [6,8]. Cooking methods such as steaming or microwaving can help reduce cooking losses. To their advantage, many of the most nutritious food sources of vitamin C, such as fruits and vegetables, are typically taken fresh or cooked. One hundred and twenty milligrammes of vitamin C can be obtained by eating five different servings of fruits and vegetables every day.
- Table 2: The Amount of Vitamin C Found in Selected Foods [12]
- Milligrams (mg) of a food per serving
- Percentage (percentage) of total DV*
- 12 cup roasted red pepper, sweet and raw 95
- 106
- a quarter cup of orange juice
- 93 103
- Orange, 1 medium (70 78), 1 small (70 78).
- 70 78 Grapefruit juice, 34 cup 70 70
- 1 medium-sized kiwifruit (64 71)
- 12 cup green pepper, sweet and raw, 60 67 calories
- 12 cup cooked broccoli (in a pot) 51 57
- a 12 cup serving of fresh strawberries sliced 49 54
- 12 cup cooked Brussels sprouts (48 53)
- 12 medium grapefruit (39 43 g)
- Broccoli, uncooked, 12 cup (39 43 calorie)
- 33 37 Tomato juice, 34 cup 33 37
- 12 cup cantaloupe (29 32 g)
- 12 cup boiled cabbage (28 31)
- a cup of raw cauliflower (26 29 g)
- 17 19 Medium baked potato 1 medium 17 19
- 1 medium-sized tomato, uncooked 17 19
- boiled spinach (about 12 cup) 9 10
- 12 cup cooked green peas (frozen or canned)
*DV is an abbreviation for Daily Value. In order to assist consumers in comparing the nutrient levels of foods and dietary supplements in the context of a balanced diet, the FDA created Dietary Reference Intakes (DVs). The daily value (DV) for vitamin C for adults and children aged 4 years and older is 90 mg [13]. Unless vitamin C has been added to the meal, the FDA does not require food labels to state the amount of vitamin C in the product. Foods that provide 20 percent or more of the Daily Value (DV) of a nutrient are considered high sources of that nutrient, while foods that provide lower percentages of the DV are nevertheless beneficial to a healthy diet.
Several foods' nutritional values are listed in the United States Department of Agriculture's (USDA's) FoodData Central external link disclaimer, which also includes an extensive list of foods containing vitamin C, grouped alphabetically by nutrient content and by food name.
Supplements for the diet
Typically, vitamin C is available in the form of ascorbic acid in supplements, which has bioavailability that is on par with the bioavailability of naturally occurring ascorbic acid found in foods such as orange juice and broccoli [14-16]. In addition to ascorbic acid with bioflavonoids and various mineral ascorbates, different vitamin C supplements are available. For example, Ester-C® comprises calcium ascorbate, dehydroascorbate, calcium threonate, lyxonate and sodium ascorbate [17], among other ingredients [18, 19, 20].
Only a few human research have looked into whether the bioavailability of vitamin C varies among the many forms available. Several studies have found that Ester-C® and ascorbic acid create the same levels of vitamin C in plasma, but Ester-C® produces much higher levels of vitamin C in leukocytes 24 hours after intake [18]. Another study found no differences in plasma vitamin C levels or urinary excretion of vitamin C among three different vitamin C sources: ascorbic acid, Ester-C®, and ascorbic acid with bioflavonoids [17]. Another study found no differences in plasma vitamin C levels or urinary excretion of vitamin C among three different vitamin C sources: ascorbic acid, Ester-C®, and ascorbic acid with bioflavonoids. In light of these data, and the relatively inexpensive cost of ascorbic acid, the authors came to the conclusion that simple ascorbic acid is the preferred source of supplemental vitamin C [17].
Vitamin C Intakes and Status in the United States
According to the National Health and Nutrition Examination Survey (NHANES) conducted in 2001–2002, mean intakes of vitamin C for adult males are 105.2 mg/day and for adult females are 83.6 mg/day, respectively, meeting the currently established RDA for the majority of non-smoking adults [19] [19, 20]. The mean intakes for children and adolescents aged 1-18 years vary from 75.6 mg/day to 100 mg/day, which is in line with the recommended daily allowance for these age groups [19]. The National Health and Nutrition Examination Survey (NHANES) did not collect data on breastfed infants and toddlers in 2001–2002; however, breastmilk is regarded an acceptable supply of vitamin C [8,14]. The use of vitamin C-containing supplements is also rather prevalent, and they contribute to the total amount of vitamin C obtained from food and beverage consumption. National Health and Nutrition Examination Survey (NHANES) statistics from 1999–2000 show that roughly 35% of individuals use multivitamin supplements (which often contain vitamin C) and 12% take a separate vitamin C supplement [20]. The National Health and Nutrition Examination Survey (NHANES) reported that roughly 29 percent of youngsters consume some sort of dietary supplement that contains vitamin C [21].
In most cases, the status of vitamin C is determined by testing plasma vitamin C levels [4,14]. Other measures, such as leukocyte counts, are also available.
Vitamin C, which is sometimes referred to as ascorbic acid, is a nutrient that is considered to be vital because of the significant part it plays in the operation of the human body. It is an antioxidant that strengthens the immune system, helps prevent cells from harm caused by free radicals, and contributes to the creation of collagen, which is necessary for healthy skin, bones, and teeth. In addition to assisting the body in absorbing iron from plant-based diets, vitamin C also has the potential to boost the body's ability to absorb other nutrients.
The amount of vitamin C that should be consumed on a daily basis is dependent not just on age and gender but also on other aspects of a person's life, such as whether or not they are pregnant. According to age and gender, the following are the vitamin C intakes that are recommended to be consumed daily:
Infants 0-6 months old should take 40 mg.
Infants between 7 and 12 months old: 50 mg
Children ages 1 to 3 years old, take 15 mg.
25 milligrams for children ages 4 to 8 years
45 milligrams for children aged 9 to 13 years
Teenage boys between the ages of 14 and 18: 75 mg
Teenage girls between the ages of 14 and 18: 65 mg
Adult men: 90 mg
Adult women: 75 mg
Pregnant women: 85 mg
Breastfeeding women: 120 mg
It is essential to keep in mind that different people have different needs when it comes to the amount of vitamin C that they take in on a daily basis, and this varies depending on a person's lifestyle, particular medical problems, and specific treatment plans. On the other hand, ingesting an excessive amount of vitamin C can have negative effects on the digestive system, including nausea and diarrhea. These symptoms can also be brought on by vomiting. Adults should not consume more than 2,000 milligrams (mg) of vitamin C in a single day.
It is also crucial to remember that vitamin C may be found in a wide variety of fruits and vegetables. Some examples of these foods include citrus fruits, strawberries, kiwi, pineapple, mango, papaya, bell peppers, broccoli, spinach, and tomatoes. Consuming a diet that is both well-balanced and abundant in fruits and vegetables will help guarantee that an adequate amount of vitamin C and other vital nutrients are taken in by the body.
In conclusion, the amount of vitamin C that is recommended to be consumed on a daily basis varies depending on age, gender, and a number of other factors. Although some people may require higher levels of vitamin C than others, it is essential to avoid consuming excessive amounts of this nutrient because doing so might result in negative side effects. Consuming a diet that is both well-balanced and abundant in fruits and vegetables will help guarantee that an adequate amount of vitamin C and other vital nutrients are taken in by the body.
