Vitamin C is an essential nutrient and one of the important water soluble vitamin. It works as an antioxidant and essential for collagen and neurotransmitters biosynthesis, as it involve in collagen synthesis reactions and helps to retain the integrity of connective tissue, bone and dentine, it deficiency can cause scurvy which is characterized by hemorrhages and abnormal bone and dentine formation. Most plants and animals produce ascorbic acid for their own requirements. However, humans cannot create ascorbic acid due to absence of an enzyme gulonolactone oxidase. Hence, vitamin C is supplement through wide variety of fruit (particularly grapefruits, lemons, blackcurrants, and oranges) and vegetables (broccoli, tomatoes, cabbage, and sweet potatoes). The current US recommended RDA for Vitamin C ranges from 100–120 mg/per day for adults. Many health benefits are associated with Vitamin C e.g. antioxidant, wound healing, anti-atherogenic, and prevents cold, facilitates recovery from burns etc.
Vitamin C, Scurvy, atherosclerosis
Sources of Vitamin C:
Fresh fruit and vegetables are the main source of vitamin C. It is well known that citrus fruits such as lemons, oranges, tangerines, limes, grapefruits and others contain vitamin C in sufficient quantity. . It is also found in green leafy vegetables like tomatoes, broccoli, peppers, cauliflower, peas, cabbage, potatoes and papayas, paprika and watermelon. Many other fruits and vegetables contain small amounts of vitamin C, too. Vitamin C also available in Synthetic form in verity of supplements like, capsules, tablets, crystalline powder and liquid form
Chemistry of vitamin C
Chemically Vitamin C or L-ascorbic acid (C6H8O6) is 2-oxo-L-threo-hexono-1,4-lactone-2,3-enediol. It is white in color and dissolves well in water. Major dietary forms of vitamin C are L-ascorbic and dehydroascorbic acid. (Davies M.B:1991)
Vitamin C protect cell from free radical damage, lower cancer risk and improve ion absorption and its deficiency cause poor wound healing, frequent cold and lung related problems
Dietary recommendations of Ascorbic acid
Vitamin C is linked to reduction of risk of chronic diseases such as cancer, cardiovascular disease, and cataract, via its antioxidant mechanisms the biochemical, clinical, and epidemiologic evidence recommend that an intake of 90–100 mg vitamin C/d is mandatory for optimum reduction of chronic disease risk. (Anitra C:1990). However, stress, smoking, alcoholism, fever, viral infections cause a rapid decline in blood levels of ascorbic acid.
Smoking increase the ascorbic acid metabolism due to its oxidation by free radicals and reactive oxygen species produced by cigarette smoking (Frei B:1981). It has been recommended that a daily intake of at least 140 mg/day is requisite for smokers to sustain a total body pool comparable to that of non-smokers taking 100 mg/day.( Kallner A:1981)
Vitamin C our health and disease
Humans lack a critical enzyme that convert glucose into ascorbic acid and hence unable to synthesis ascorbic acid independently. Therefore, humans must get the all of their vitamin C needs in the diet
People having low levels of Ascorbic acid are more likely to have a heart attack, stroke, or peripheral artery disease, all possible consequences of having atherosclerosis in addition to deadly scurvy
Vitamin C Deficiency and Scurvy
Scurvy resulting from shortage of vitamin C, since lacking of vitamin make collagen too unstable to carry out its function. Scurvy results in the development of brown spots on the skin, spongy gums, and blood loss from all mucous membranes
The development of scurvy occurs slowly, usually symptoms emerging after 60-90 days of a vitamin C poor diet. The commencement of scurvy has been noted to progress in four stages. In the first stage, people start to feel lazy. The muscles ache, particularly in the legs and lower abdomen.
During the second phase patients’ gums swell up, bleed, irritate. Further more, teeth become loose at the roots. Patients also start feeling pain throughout the joints and muscles.
Whe the third stage arrive, the gums turn out to be putrid and begin to smell like rotting flesh. The flesh becomes infected and the skin will hemorrhage. The skin, particularly in the legs and feet, develop ulcers.
In the fourth and final stage, the body develops high fevers. Black spots develop on the skin, the body begins to shiver, and finally death occurs.
Even in stage four, curing with high levels of vitamin C will turn around the effects of scurvy and the patient will return to good health (Mayberry:2004)
Vitamin C and cardiovascular disease
Correlation studies show an inverse relationship between ascorbic acid ingestion and cardiovascular disease mortality. In persons with high total cholesterol concentrations, more than or equal to 5.20 mmol/L and less than full tissue saturation, increasing concentration of ascorbic acid have a beneficial effect on total cholesterol. Study of the literature related to groups having high danger for coronary heart disease shows smokers, diabetics, and hypertensive peoples have low plasma vitamin C levels. (J A Simon: 1992)
Vitamin C and atherosclerosis
Vitamin C is necessary for the body to produce collagen that is a part of normal cartilage. Cartilage is damaged in osteoarthritis (OA), putting strain on bones and joints. In addition, some researchers suggest free radicals — molecules formed by the body that can damage cells and DNA — may also be involved in the damage of cartilage. Antioxidants such as vitamin C prevent the oxidation of LDL limit the damage caused by free radicals. However, that said, no data suggests that taking vitamin C supplements will aid to prevent atherosclerosis. Though evidence shows that people who consume diets rich in vitamin C are less prone to arthritis (Frei B:1989)
Common cold and Vitamin C
It is widely accepted that Vitamin C prevention or give relief from common cold. The metabolism of Vitamin C during the cold, and after vanishing of all the symptoms, has been studied by investigating the plasma and leucocyte. Vitamin C notably reduces the harshness and total intensity of colds in girls, but does not redused cold symptoms in boys at a daily dose of 500 mg. During colds, ascorbic acid is moved out of the leucocytes into the plasma, where it is quickly metabolized in both sexes, but this effect is more prominent in females. There is a considerable positive correlation between metabolic utilization of Vitamin C during colds and strength of cold symptoms (C.W.M Wilson etal: 1973)
Vitamin C and Cancer
Nobel laureate Pauling and Cameron supported use of high doses of Vitamin C (> 10 g/day) to treat and check cancer (Cameron E atal : 1979). However, clinical studies on cancer patients done at Mayo Clinic gave no major differences between vitamin C and placebo groups regarding survival time (Moertel CG etral : 1985). Cameron and Pauling (Cameron E: 1973) believed that Vitamin C fights cancer by encouraging collagen synthesis and thus stop tumors from attacking other tissues. However, researchers now consider that Vitammin C check cancer by neutralizing free radicals prior to they can harm DNA and begin tumor growth and or may act as a pro-oxidant helping body’s own free radicals to wipe out tumors in their early stages.
Vitamin C have also function in
v Lowering blood pressure
v Enhancing immune system function
v Healthy Gums
v Reduce effect of sun burn
v Healing burns and wounds
Vitamin C is not only regulate many body functions its deficiency is also related to number of diseases like scurvy, coronary heart diseases, atherosclerosis even death in severe cases. In addition vitamin also regulate and function to enhance immune system, healing burns and wounds, healthy gums and many more beneficial effect, it is widely distributed in food of plant and fruit particularly citrus and its recommended daily intake is necessary to overcome many diseases and symptoms related to its deficiency
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Hammad Shafiq1*, Saba Fiaz 1, Nadeem Iqbal1, Ahmad Mahmood2
1 Department of Food Technology, PMAS-Arid Agriculture University, Rawalpindi
2 Department of Agronomy, University of Agriculture, Faisalabad.
* Corresponding author: [email protected]