Written on the 29 March 2016 by The Compounding Team
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. Unlike most mammals and other animals, humans do not have the ability to make ascorbic acid and must obtain vitamin C from external sources.
Inside our bodies, vitamin C functions as an essential cofactor in numerous enzymatic reactions, e.g., in the biosynthesis of collagen, carnitine, and catecholamines, and as a potent antioxidant. (See also The Wonder of CoQ10 for more about antioxidants)
Vitamin C supplements are available in many forms, but there is little scientific evidence that any one form is better absorbed or more effective than another -Contact Your Solution Compounding Pharmacy for more information. We compound Vitamin C to suit your particular situation!
There is no scientific evidence that large amounts of vitamin C (up to 10 grams/day in adults) exert any adverse or toxic effects. An upper level of 2 grams/day is recommended in order to prevent some adults from experiencing diarrhoea and gastrointestinal disturbances.
Function and Health support / Disease Treatment
Two major functions of vitamin C are as an antioxidant, and as an enzyme cofactor. Even in small amounts vitamin C can protect indispensable molecules in the body, such as proteins, lipids (fats), carbohydrates, and nucleic acids, (DNA and RNA), from damage by free radicals and reactive oxygen species, (ROS). These are generated during normal metabolism by active immune cells, and through exposure to toxins and pollutants (e.g., certain chemotherapy drugs and cigarette smoke). Vitamin C is known to regenerate vitamin E from its oxidized form. Vitamin C increases the bioavailability of iron from foods by enhancing intestinal absorption of non-heme iron.
Symptoms of vitamin C deficiency, such as poor wound healing and lethargy, result from impairment of certain enzymatic reactions and insufficient collagen, carnitine, and catecholamine synthesis. (-see also Acetyl-L-carnitine -May just help). Research also suggests that vitamin C is involved in the metabolism of cholesterol to bile acids, which may have implications for blood cholesterol levels and the incidence of gallstones.
Severe vitamin C deficiency has been known for many centuries as the potentially fatal disease, scurvy. Symptoms of scurvy include subcutaneous bleeding, poor wound closure, and bruising easily, hair and tooth loss, and joint pain and swelling. Such symptoms appear to be related to the weakening of blood vessels, connective tissue, and bone, which all contain collagen. Early symptoms of scurvy like fatigue may result from diminished levels of carnitine, which is needed to derive energy from fat.
The recommended intake for smokers is 35 mg/day higher than for non-smokers, because smokers are under increased oxidative stress from the toxins in cigarette smoke and generally have lower blood levels of vitamin C.
A number of observational studies have found increased dietary vitamin C intake to be associated with decreased risk of stomach cancer, and laboratory experiments indicate that vitamin C inhibits the formation of carcinogenic N-nitroso compounds in the stomach. Infection with the bacteria, Helicobacter pylori (H. pylori), is known to increase the risk of stomach cancer and is associated with lower vitamin C content of stomach secretions. More recent research suggests that vitamin C supplementation may be a useful addition to standard H. pylori eradication therapy in reducing the risk of gastric cancer.
Oxidative damage contributes to the formation of cataracts, (cloudiness or opacity in the lens that interferes with the clear focusing of images on the retina). Decreased vitamin C levels in the lens of the eye have been associated with increased severity of cataracts.
Gout is characterized by abnormally high blood levels of uric acid (urate). Urate crystals may form in joints, resulting in inflammation and pain, as well as in the kidneys and urinary tract, resulting in kidney stones. The results of a study indicated that supplemental vitamin C may be helpful in the prevention of gout.
Role in immunity
Vitamin C affects several components of the human immune system; for example, vitamin C has been shown to stimulate both the production and function of leukocytes, (white blood cells), especially neutrophils, lymphocytes, and phagocytes. Neutrophils, mononuclear phagocytes, and lymphocytes accumulate vitamin C to high concentrations, which can protect these cell types from oxidative damage. Phagocytic leukocytes also produce and release cytokines, including interferons, which have antiviral activity. Vitamin C has been shown to increase interferon levels in vitro.
The ability of blood vessels to relax or dilate, (vasodilation), is compromised in individuals with atherosclerosis. Damage to the heart muscle caused by a heart attack and damage to the brain caused by a stroke are related, in part, to the inability of blood vessels to dilate enough to allow blood flow to the affected areas. The pain of angina pectoris is also related to insufficient dilation of the coronary arteries. Many randomized, double-blind, placebo-controlled studies have shown that treatment with vitamin C consistently results in improved vasodilation in individuals with coronary heart disease, as well as those with angina pectoris, congestive heart failure, diabetes, high cholesterol, and high blood pressure.
A recent meta-analysis of short-term trials indicated that vitamin C supplementation reduced blood pressure in both healthy, normotensive and hypertensive adults. It is important for individuals with significantly elevated blood pressure not to rely on vitamin C supplementation alone to treat their hypertension, but to seek or continue therapy with anti-hypertensive medication, as well as through diet and lifestyle changes in consultation with their health care provider.
A strong inverse association between plasma vitamin C and risk of diabetes mellitus has been reported in a cohort study of 21,831 men and women. Cardiovascular disease (CVD) is the leading cause of death in individuals with diabetes. Evidence that diabetes is a condition of increased oxidative stress led to the hypothesis that higher intakes of antioxidant nutrients could help decrease CVD risk in diabetic individuals. It is possible that genetic differences may influence the effect of vitamin C supplementation on CVD risk in diabetic patients.
Studies in the 1970s and 1980s conducted by Linus Pauling, Ewan Cameron, and colleagues suggested that very large doses of vitamin C infused intravenously for 10 days, followed by at least 10 grams/day orally indefinitely, were helpful in increasing the survival time and improving the quality of life of terminal cancer patients. The route of vitamin C administration is critical. Compared to orally administered vitamin C, intravenous vitamin C can result in 30 to 70-fold higher plasma levels of vitamin C. Currently, results from controlled clinical trials indicate that intravenous vitamin C is generally safe and well tolerated in cancer patients.
Common cold -prevention
In the past 40 years, numerous placebo-controlled trials have examined the effect of vitamin C supplementation on the prevention and treatment of colds. Meta-analysis of placebo-controlled trials evaluated the effect of vitamin C supplementation on the incidence, duration, or severity of the common cold when taken as a continuous daily supplement, or as therapy upon onset of cold symptoms.
Regular supplementation with vitamin C, (0.25 to 2 grams/day), did not reduce the incidence of colds in the general population; however, in participants undergoing heavy physical stress, (e.g. marathon runners, skiers, or soldiers in subarctic conditions), vitamin C supplementation halved the incidence of colds. A benefit of regular vitamin C supplementation was also seen in the duration of colds, with a greater benefit in children than in adults. The pooled effect of vitamin C supplementation was a 14% reduction in cold duration in children, and an 8% reduction in adults.
Exercise-induced bronchoconstriction is a transient narrowing of the airways that occurs after exercise and is indicated by a 10% decline in Forced Expiratory Volume in 1 second (FEV1). Asthmatic participants received either vitamin C or placebo before exercise. Compared to placebo, vitamin C administration significantly reduced the exercise-induced decline in FEV1 by 48%.
Although the use of lead paint and leaded gasoline has been discontinued in many countries, lead toxicity continues to be a significant health problem, especially in children living in urban areas. Children who are chronically exposed to lead are more likely to develop learning disabilities, behavioural problems, and to have a low IQ. In adults, lead toxicity may result in kidney damage, high blood pressure, and anaemia.
Several cross-sectional studies report an inverse association between vitamin C status and blood lead level (BLL). A US national survey of more than 10,000 adults found that BLL were inversely related to serum vitamin C levels.
Cigarette smoking or second-hand exposure to cigarette smoke contributes to increased BLL and a state of chronic low-level lead exposure. An intervention trial in adult male smokers found that supplementation with vitamin C resulted in significantly lower BLL over a four-week treatment period compared to placebo.
Mineral salts of ascorbic acid are buffered and, therefore, less acidic than ascorbic acid. Some people find them less irritating to the gastrointestinal tract than ascorbic acid. Sodium ascorbate and calcium ascorbate are the most common forms, although a number of other mineral ascorbates are available. Ask Your Solution Compounding Pharmacists for more information that will suit you as an individual.
Ascorbyl palmitate is a vitamin C ester (i.e. ascorbic acid linked to a fatty acid). In this case, vitamin C is esterified to the saturated fatty acid, palmitic acid, resulting in a fat-soluble form of vitamin C. Ascorbyl palmitate has been added to a number of skin creams due to interest in its antioxidant properties, as well as its importance in collagen synthesis.
A number of drugs are known to lower vitamin C levels, requiring an increase in its intake. Estrogen-containing contraceptives (birth control pills) are known to lower vitamin C levels in plasma and white blood cells. Aspirin can lower vitamin C levels if taken frequently. There is some evidence, though controversial, that vitamin C interacts with anticoagulant medications, (blood thinners), like warfarin. High doses of vitamin C have also been found to interfere with the interpretation of certain laboratory tests (e.g., serum bilirubin, serum creatinine, and the guaiac assay for occult blood). It is important to inform one's health care provider of any recent supplement use.
Linus Pauling Institute Recommendation
Based on the combined evidence from metabolic, pharmacokinetic, and observational studies and from randomized controlled trials, it has been argued that sufficient scientific evidence exists to support an optimum, daily vitamin C intake of at least 200 mg/day, which is substantially higher than the current RDA (Recommended Dietary Allowance). Most multivitamin/mineral supplements provide 60 mg of vitamin C. To make sure you meet the Institute's recommendation, supplemental vitamin C in two separate 250-mg doses taken in the morning and evening is recommended.
Older adults (>50 years)
Some older populations have been found to have vitamin C intakes considerably below the RDA for women and men. Vitamin C intake may be particularly important for older adults who are at higher risk for age-related chronic diseases. Evidence suggests that the efficiency of one of the molecular mechanisms for the cellular uptake of vitamin C declines with age. Vitamin C intake is therefore especially important for older adults who are at higher risk for chronic diseases caused, in part, by oxidative damage, such as heart disease, stroke, certain cancers, and cataract.
The above are some highlights from certain research, and other publications to inform patients of some of the benefits of Vitamin C. Self-medication with Vitamin C only, or in conjunction with certain other medications, is not recommended for serious diseases, without consultation with a qualified health care provider. See for example Hypertension and Drug interactions above.
If in doubt, just contact Your Solution Compounding Pharmacy for more information, or visit us at 1/6 Pine Rivers Office Park, 205 Leitchs Rd. Brendale, QLD.
Further reading and References:
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