Vitamin C ( Ascorbic Acid )
A plethora of vital biochemical functions are performed by the vitamin C or ascorbic acid in the human body - these actions occur at the cellular level. This essential vitamin works as a co-enzyme playing an important role in the metabolism of amino acids. The ascorbic acid also facilitates the biochemical conversion of the B complex vitamin folic acid (folate) to the active form of folate called folinic acid - this conversion is required for the proper utilization of folate by the human body. Cell level respiration is also heavily influenced by the presence of the vitamin C. The formation of collagen and other fibrous tissues is by far primary role performed by vitamin C in the human body. The proteins found in the skin, the tendons, the bones, the teeth, the cartilaginous tissues and general connective tissues is composed of collagen - this protein plays a supportive functional role in the human body. The vitamin C is also required for the maintenance of proper structural and functional integrity in the capillary walls and larger blood vessels. The collagen acts as an intercellular matrix wherever any tissue is growing, is in the developing process or is repairing itself following injury - this base matrix of collagen serves a structural function and is the main framework on which most tissues are formed. The matrix may not be set down or formed properly if the levels of vitamin C in the body are not adequate, a deficiency of collaged may also leave the matrix formation incomplete or deformed. Similarly, tissue structures already constructed will start to deteriorate in the event of a prolonged deficiency of the vitamin C in the body. Therefore, it can be said that the proper growth, the correct development and the maintenance of just about all the tissues in the body depend on the presence of vitamin C in the right amounts at the cellular level.
The pathway of vitamin C absorption goes like this, almost all the vitamin C in the body is absorbed from the digested food in the small intestine, the nutrient is then circulated in the blood and stored in various tissues in the body. Compared to any other tissue, high amounts of the vitamin C are stored in the adrenal glands, in the pituitary gland, the thymus and in the corpus luteum of females. Higher than normal levels of the vitamin C is to be found in all metabolically active tissues due to the increased requirement of this nutrient in developing tissues and organ systems.
The highest concentrations of the vitamin C can be found in the adrenal glands among all storage sites for this vitamin in the human body. Vitamin C mobilization in the adrenal glands peaks whenever the organism is stressed by any factor, this mobilization of vitamin C occurs from all other tissues as well and large amounts of the vitamin C start to appear in the urine of the animal. The importance of the vitamin C in promoting the ability of the body to withstand stress is indicated by the rapid mobilization of vitamin C during times of stress. The ability to synthesize vitamin C is also rapidly loss by a deficiency of the vitamin A, at least in laboratory rats, the adrenal glands of such rats also starts to dysfunction due to this factor. Normal functioning in the adrenal glands is restored by supplements of vitamin C in such cases. Vitamin C deficiency symptoms in many humans - symptomatic deficiency disorders such as scurvy - can be similar to the symptoms seen in cases of adrenal insufficiency including generalized and persistent fatigue, generalized muscle weakness, the presence of digestive disorders and a greatly reduced capability to tolerate stress.
The anti-oxidant function of vitamin C is another beneficial role played by the vitamin in the body, as an antioxidant the vitamin helps protect the cells and the various tissues from the damaging effects of oxidation from free radicals released in the cells as part of normal metabolic reactions. As more research is being undertaken on oxidation by free radicals as the basis for many human disease states, the anti-oxidant role of vitamin C's is of extreme importance in the treatment of many well known diseases. The requirement of the vitamin C in the tissues is also raised by the stimulation of muscle tissues during physical activity, as exercised muscle increases the rate at which vitamin is utilized in the metabolism of the cells. The reason for generalized muscle weakness in cases of vitamin C deficiency could be the linked to this increased rate of vitamin C use in the muscles.
Simply put the amount of vitamin C needed in the body to prevent scurvy from affecting otherwise healthy individuals is the RDA for vitamin C. The acute form of the disease is what scientists who set the standard RDA mean when they say scurvy - one of the oldest recognized vitamin deficiency disorders. However, the onset of scurvy may not be simple and several doctors and clinical researchers believed that cases of scurvy can come about with a much more insidious development of symptoms, or that a whole range of possible disorders can begin from localized scurvy affecting certain areas or tissues of the human body. That chronic or latent type of scurvy is prevalent in the modern world is a suggestion made by many scientists who base this belief on clinical evidence gathered with respect to vitamin C and disease states. What this implies is that the ability to resist diseases as insignificant as bleeding gums and easy bruising or even as severe and life changing as cancer and heart disease of millions of people around the world is seriously impaired and weakened.
An increased requirement for the vitamin C or a vitamin C deficiency in the body can be brought about by many different factors. Individuals who do not like eating acidic foods for example, tend to be affected by vitamin C deficiency at some stage in their life - symptoms seen in these individuals tends to be minor. Compared to people who do not smoke, all smokers in general, tend to have lower tissue levels of the vitamin C. The vitamin C levels in the body are known to be directly depleted by smoking. One factor contributing to the higher then average death rate from cancer and heart disease of smokers could be this depletion of vitamin C stores in the body.
People affected by liver disease have lower vitamin C levels then healthy people do, this deficiency or low level of the vitamin C can be directly attributed to the sudden increase in the toxic effects of the different medications used in the treatment of the liver disorder. Low tissue levels of the vitamin C also tends to be evident in patients suffering from hyperthyroid problems.
A deficiency of the vitamin C can also be induced in the human body by the long term use of several types of medications and certain classes of drugs. These medications include compounds like the adrenal corticosteroids - these can in fact produce scurvy like symptoms in the person. A vitamin C deficiency is also induced by long term use of estrogen bearing medications like different oral contraceptives and all menopausal drugs used by women. Drugs like the barbiturates and antibiotics like the compound tetracycline can also induce deficiency states. The urinary rate of excretion of the vitamin C is increased by a factor of three through the use of aspirin.
The presence of any kind of disorder that results in an increase in the total blood levels of the trace mineral copper also increases the requirement for vitamin C in the body. Significant amounts of the trace mineral copper can and does enter the human body through the water that is piped through plumbing pipes made from copper - this is one way in which copper comes into the diet. The detoxification of excess levels of copper in the body is apparently influenced by vitamin C in some way.
A wide range of doses types are available for supplemental vitamin C, these doses range from a few milligrams per dose to doses that can be in excess of 1000 mg (or a gram). One should make sure to carefully examine all the vitamin C tablets before purchase for dosage and other requirements, particularly products advertised as natural or rose hips or acerola must be checked for product information. The usual mode by which these supplemental forms of the vitamin C are made involves using some synthetic vitamin C and adding small quantities of acerola berry or rose hips to mask the synthetic nature of the product. Vitamin C which is "synthetic" is similar in all respects with the naturally occurring vitamin C in plant and animal sources. The synthetic form is produced by fermenting glucose, a process that is essentially similar to the way in which vitamin C is produced in natural sources. The cost is the deciding factors as the so called natural vitamin C tablets may be sold by clever marketers for a much higher price than the same dose type of tablet which has been plainly labeled "ascorbic acid"- this is just a marketing gimmick and natural sources of vitamin C are in no way better than synthesized forms of the same vitamin. The sodium ascorbate compound form of the supplemental vitamin C is also available in many drug stores. The powdered form of vitamin C is also available in many drug stores; this supplemental form of the vitamin is the cheapest way to supplement the vitamin.
Vitamin C is found in very high amounts in plant foods such as all citrus fruits and their juices, in fruits like strawberries, in cantaloupes, in all raw vegetables such as peppers, herbs like parsley, broccoli and cauliflower, in kale, in Brussels sprouts and turnip greens, in vegetables like cabbage, tomatoes and potatoes and bean sprouts among others. The method employed in growing, storing and preparing these vegetables decides about the level of vitamin C found in these plant foods. The vitamin C content of any plant food is determined by the amount of sunlight the plant receives, the greater the amount of incident sunlight, the more vitamins produced in the plant. Additionally, the vitamin C is chemically susceptible to the damaging actitsons of oxidation - a significant amount of the vitamin can be lost by exposing the vitamin C to ambient air. Severe losses of the vitamin from food can ensue if the food is steamed for long periods of time, if it is washed again and again, or if it is soaked or canned in liquids - the reason is that vitamin C is soluble in water. A complete loss of the vitamin C content of citrus juice may result when the product is stored at warm temperatures for a long period of time.
While societies in the West are do not suffer from scurvy - a serious deficiency symptom of vitamin - and the disease is rare these days, the amounts of vitamin C consumed by most people is not at the optimal rate of intake according to most nutritional scientists. The physical symptoms include generalized and persistent fatigue, easily bruised and bleeding gums - these symptoms are aggravated as scurvy becomes full blown. Low levels of vitamin C are also evident in smokers and such individuals normally need a much higher daily intake of the vitamin just to maintain vitamin C levels at levels that are normal for non-smokers.
Vitamin C at daily intake levels of 500 mg to 1,000 mg is a suggestion made by most doctors of natural medicine. In medical research, the dosage levels used do not exceed 1,000 mg of vitamin C a day. At the same time, it is not rare to supplement with even greater levels of the vitamin - at about 10,000 mg per person daily. While the recommended levels of vitamin C dosage with respect to the prevention of heart disease, may be as little as 100 to 200 mg of vitamin C per person per day.
Clinical researchers who are studying the effects of vitamin C on the human body at the present time are of the persuasion that using 200 mg of the vitamin daily may raise the blood levels of the vitamin in healthy people to as high as it can go. They believe that supplements at dosage levels greater than this, can results in an increase in a rate of excretion of the vitamin C to a level that is similar to the rate of intake - what this means is that vitamin C does not stay in the body or accumulates like other nutrients, in other words, it has a high turnover rate. Therefore, healthy people may not need to take vitamin C at dosage levels exceeding 200 mg daily as such dosages may not benefit the person in any way. Similar clinical studies have also resulted in evidence that suggest a dosage level of 200 mg is about the right dosage level for all healthy people, however such dosage levels are still to be used on sick individuals.
Side effects and cautions
While many people can tolerate very high amounts of the vitamin C, many individuals are affected by symptomatic diarrhea following the consumption of as little as a few thousand milligrams of the vitamin C daily - many other people can take ten times this dosage. The store of the mineral copper in the human body can be depleted by the consumption of very high levels of vitamin C, copper is also an essential nutrient and it's deficiency can also induce symptoms in the person - for this reason, vitamin C supplements must be used with care especially when supplementing with high doses for long periods of time. Copper must be supplemented at adequate doses whenever a person uses supplements of the vitamin C to ensure that stores of the mineral are not depleted when vitamin C is used at very high doses. Many of the multi-vitamin and multi-mineral supplements contain copper. The rate of absorption of the essential mineral iron may also be positively affected by vitamin C, the effect is however, very mild and vitamin C must not be used to increase the rate of absorption of iron. The recycling of the antioxidant compound vitamin E is also regulated by vitamin C.
As excess vitamin C in the body undergoes chemical conversion into oxalate leading to a rise in the levels of oxalate in the urine, the suggestion is that people who are affected by kidney stones may be better off if they avoid all supplements of vitamin C - accumulated oxalate is one of the main reasons for kidney stone formation. However, when it was first noticed, the role of vitamin C and its conversion were questioned as the conversion of the vitamin to oxalate occurred only after the urine had been excreted. Recent evidence garnered from research that used new scientific methodology has ruled out this problem and it is now known that as little as 1 gram of vitamin C daily can lead to a rise in levels of oxalate in the urine even in some people - this effect was true for individual without a history of kidney stones as well. A very dramatic increase in the levels of oxalate excreted in the urine was observed in one particular case, where 8 grams of the vitamin C was used per day, this raising of oxalate levels in the body also led to kidney stone crystal formation and brought about the appearance of bloody urine in the affected person. Supplements of vitamin C at large doses - one gram a day - must not be taken by individuals affected by kidney stones or with a medical history indicating susceptibility to stone formation. It is believed that significantly lower amounts of the vitamin at 100 to 200 mg daily are safe and no medical concern need to be raised at such dosage levels.