The role of vitamin C in prevention and treatment of scurvy is well accepted. In spite of having long history as the candidate of alternative therapy for the prevention and treatment of cancer, still there is no common conclusion on the topic. However, its biochemical reaction as an antioxidant and its immunostimulating effects drew further attention towards its health beneficial effects. Current official recommended dietary allowance in most of the countries is higher than what is needed for the prevention of scurvy, but research result suggested that it is far less to obtain optimum health. Therefore, especially for the prevention of chronic illness such as cancer, hypertension, Alzheimer’s diseases etc., it is recommended to consume more fruits and vegetables together with the vitamin C supplements. Evaluating the vitamin C efficiency and safety with current literature, up to 1 g/day supplement of vitamin C has been suggested to be needed for optimal health. In addition, male population compared to female population, older population compared to younger population, smoking population compared to non-smoking population and stressed population compared to non-stressed population need larger amounts of vitamin C to obtain health beneficial effects.
Vitamin C (ascorbic acid) is one of the essential components in human physiology working as a water-soluble antioxidant and enzyme cofactor. Humans do not synthesize ascorbate, therefore we need to administer it through diet or supplements. We must assure a sufficient intake of vitamin C in order to define its role for the prevention or treatment of various diseases.Britons are wasting million of pounds buying Vitamin C supplements to ward off colds after researchers found they have no benefit at all. Academics who looked back at 67 studies examining the effectiveness of cold preventions and remedies discovered that few live up to the hype. Traditional remedies like echinacea, ginseng, vapour rubs and cough medicine were found to have no clear benefits while antibiotics were likely to cause more harm than good, the researchers concluded. Out of all the studies, only taking a zinc supplement was found to be beneficial at preventing colds. Drugs like ibuprofen and paracetamol were found to be useful at reducing fever and taking honey soothed a sore throat.
General hand washing was also effective at preventing the illness spreading, the authors concluded. The findings mean that Brits are wasting millions every year trying to ward off colds. “The best evidence for the prevention of the common cold supports hand-washing and possibly the use of zinc supplements,” said Dr Michael Allan, of the Department of Family Medicine, at the University of Alberta. “Although self-limiting, the common cold is highly prevalent and may be debilitating. It causes declines in function and productivity at work and may affect other activities such as driving “Its impact on society is large.” At least two trials indicated that children who took 10 or 15mg of zinc sulphate daily had lower rates of colds and fewer absences from school due to colds. Although the studies carried out on children the researchers concluded that: “there is no biblical reason why zinc could work only in children and not adults.” The common cold affects adults approximately 2-3 times a year and children under age 2 approximately 6 times a year.
Symptoms such as sore throat, stuffy or runny nose, cough and malaise are usually worse in days 1-3 and can last 7-10 days, sometimes as long as 3 weeks. Only about one in 20 colds are caused by bacteria, with the majority caused by a virus which cannot be treated with anti-biotics. Vitamin C became popular in the Seventies after Nobel laureate Linus Pauling concluded it could prevent and alleviate colds. It is the UK’s most popular vitamin with annual sales of around £36 million. It is a dietary antioxidant and so can neutralise the effects of free radicals and support the immune system's host defence. However a recent Cochrane review found that regular Vitamin C supplements had no effect on common cold incidence although it may shorten the time the disease lasts. Large doses of Vitamin C are also likely to cause nausea, diarrhoea and stomach cramps. The researchers also debunked other traditional cures. “The role of ginseng in preventing common colds is questionable,” said Dr Allan.
“Studies of exercise, garlic and homeopathy showed unclear evidence of benefit, whereas those of Vitamin D, and Echinacea showed no evidence of benefit.” The report authors also found that vapour rub containing camphor, menthol and eucalyptus oil, applied to the neck and chest had virtually no benefit and could lead to a rash or a burning sensation. Researchers also found that ibuprofen and acetaminophen help with pain and fever. The researchers said there is some evidence that probiotics may help prevent colds, although the types and combinations of organisms varied in the studies as did the formulations, making comparison difficult. Graham Keen, executive director of the Health Food Manufacturers Association said: “This new review contradicts pre-existing, robust evidence demonstrating a positive impact of vitamin C supplements in this area. "For example, a large-scale Cochrane meta-analysis published in 2013 found that regular vitamin C supplementation seems to have a consistent effect in reducing the duration and severity of common cold symptoms.
“It is also important to note that these products are not designed for curing or preventing the spread of disease. Daily vitamin supplements provide important nutritional insurance for millions of users looking to safeguard their nutritional intake alongside a healthy diet.” The study was published in the Canadian Medical Association Journal.Recommended daily allowance (RDA) for an adult is about 90 mg/day. If you smoke, add 35 for a total of ~125 mg/day. While RDA is set based on recommendations for prevention of deficiency, it's been shown that anything above that in a healthy person doesn't seem to improve biomarkers of cellular oxidant stress (at least that of endogenous lipid peroxidation).If you really feel the need to be saturated with vitamin C "just in case", your blood level hits maximum at ~400 mg/day; anything above that is peed out, so don't waste your time and/or money! :-)Sources:http://www.ncbi.nlm.nih.gov/pmc/...http://lpi.oregonstate.edu/infoc...EDIT: Just came across an interesting bit of information in a prof's powerpoint while studying the kidney, and thought I'd share:2000 mg per day of Vitamin C supplement increases urine oxalate (a component of a common variety of kidney stone) by 22%.
Men who take 1000 mg or more vs. the RDA of 90 mg have up to 40% higher risk of stone formation. So people who are either at risk of forming calcium oxalate stones or have a history of forming them should be instructed to stop vitamin C supplements.Mind you, everyone's risk for forming kidney stones is widely different, so just take the above as a cautionary note of something to keep in mind. :-)It depends on your bodies stress level. In healthy state, plasma is saturated by taking 3g every 4-5 hours. In diseased state, you can take higher then 100g as during disease vitamin C metabolism changes.Jae Won Jo, is wrong, and he should read newer pharmakokinetic studies on vitamin C.15While a variety of perspectives is presented above, I believe you may benefit from reviewing another source - which in my perspective appears science-based and less biased than individual articles (although one could argue otherwise - it’s only my opinion):Vitamin C | Linus Pauling Institute | Oregon State UniversityIf you only care about conclusions and not details, here is the gist:current RDA: <= 125mg/daystudies-based optimum daily: at least 200 mg/dayNational Institutes of Health: near-maximal concentrations (in plasma and circulating cells) of vitamin C: 400 mg/dayLinus Pauling Institute recommends: at least 400 mg daily (supplemental vitamin C in two separate 250-mg doses taken in the morning and evening is recommended)"your blood level hits maximum at ~400 mg/dayPet Bounce is a complete
multivitamin formulated especially for your cat and dog. Whether they’re big or small, canine or feline, they will benefit from this advanced formula created specifically to support their health and well-being.Most dogs receive a complete and balanced diet - including necessary vitamins and minerals - from commercially processed dog food, according to the FDA. Dogs fed a homemade diet may need supplements. “It’s absolutely critical, but it shouald be done to match the diet,” Wynn says. “You can’t just create a meal and give your dog a vitamin.” Check with a veterinarian or nutritionist for help in determining what, if anything, is needed.If your dog is eating a well-balanced and nutritionally complete dog food that is made from high-quality ingredients, a vitamin and mineral supplement is not necessary and could in fact do more harm than good. Because reputable pet food manufacturers go to great lengths to make sure that your dog’s meals contain the right proportions of vitamins and minerals, and adding more can throw this delicate balance completely out of whack.