Megadoses May Lead To Kidney Stones
According to the National Institutes of Health Office of Dietary Supplements, the highest recommended dietary allowance for vitamin C is 120 mg per day. Thats only for 19+ year old women who are breastfeeding. Smokers are also advised to use an extra 35 mg per day.
For non-smokers and those who are not pregnant, the RDA is 90 mg for men and 75 mg for women.
All of those amounts are said to be much higher than the minimum required to protect against vitamin C deficiency.
Being water soluble, you can use more safely and there is plenty of science to suggest benefits of doing so. How much vitamin C should I take per day?
The following are the Tolerable Upper Intake Levels according to the same U.S. government source.
|Tolerable Upper Intake Levels for Vitamin C|
|*Formula and food should be the only sources of vitamin C for infants.|
In adult men and women, 2,000 mg per day of ascorbic acid is considered to be the maximum safe amount to use on a long-term basis. This limit is for the total combined intake coming from both food and supplement sources. Exceeding this dose will increase the risk of side effects.
What is megadosing? There is no official definition but generally its when nutrients are eaten or consumed in amounts far greater than the Tolerable Upper Intake Levels.
Lets begin with what might be happening with even lower amounts.
Of course the next logical question is, how many milligrams of the vitamin were they taking per day?
Vitamin C Shortens And Alleviates The Common Cold
The effect of vitamin C on the duration and severity of the common cold has been studied in regular supplementation trials and in therapeutic trials. Regular supplementation means that vitamin C was administered each day over the whole study period, and the outcome is the duration and severity of colds that occurred during the study. Therapeutic vitamin C trial means that vitamin C administration was started only after the first common cold symptoms had occurred and the duration of colds were then recorded.
In regular supplementation studies, 0.2 g/day of vitamin C decreased the duration of colds by 9% . When the dosage was 1 g/day of vitamin C, the mean duration of colds was shortened by 8% in adults and by 18% in children. Vitamin C also significantly alleviated the severity of the colds.
What Are The Preferred Sources Of Vitamin C
There is no reason to take vitamin supplements if you eat a healthy whole food plant-based diet. Vegetables and fruits are good sources of vitamin C. You can see analytically the list with the richest foods in vitamin C here. For instance, kale, broccoli, or peppers are particularly high in vitamin C.
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Vitamin C Dosage Requirements Are In Flux
Vitamin C is a potent antioxidant. Its job is to neutralize reactive oxygen species . Free radicals are missing an electron, and, the unscrupulous fiends that they are, they steal electrons from healthy cells, making them unstable. Each Vitamin C molecule and that of other antioxidants like Vitamin E, selenium, and Glutathione has an electron to spare, so Vitamin C donates that electron to the free radicals, thus neutralizing them. At that point, the antioxidant has now lost its potency and leaves the body as waste, its job done. When you have elevated free radicals due to high stress or illness, it makes sense that you would require a higher Vitamin C dosage than on days when your free radical content is at baseline levels.
Thats why smokers have a higher Vitamin C RDA than non-smokers. Smoking generates free radicals in the body, so people who smoke need a higher Vitamin C dosage to neutralize these extra free radicals in addition to the standard ones to which we are exposed just by living in the 21st century.
So, what is the optimal Vitamin C dosage? Well, that depends more on the content of free radicals in your body at any given moment than age or gender.
Just note that higher doses can interfere with certain medications, so its always best to consult your physician if you are taking prescription medications before taking high-dose supplements like a micronutrient-conscious pirate returning from months on the high seas.
Early History On Vitamin C And Infections
Vitamin C was identified in the early twentieth century in the search for a substance, the deficiency of which would cause scurvy . Scurvy was associated with pneumonia in the early literature, which implies that the factor that cured scurvy might also have an effect on pneumonia.
Alfred Hess summarized a series of autopsy findings as follows: pneumonia, lobular or lobar, is one of the most frequent complications and causes of death and secondary pneumonias, usually broncho-pneumonic in type, are of common occurrence and in many epidemics constitute the prevailing cause of death . He later commented that in infantile scurvy … a lack of the antiscorbutic factor which leads to scurvy, at the same time predisposes to infections … Similar susceptibility to infections goes hand in hand with adult scurvy . In the early 1900s, Casimir Funk, who coined the word vitamin, noted that an epidemic of pneumonia in the Sudan disappeared when antiscorbutic treatment was given to the numerous cases of scurvy that appeared at about the same time .
Early literature on vitamin C and infections was reviewed by Clausen , Robertson , and Perla and Marmorston . Those reviews are thorough descriptions of the large number of early studies on the topic of this review. Scanned versions of those reviews and English translations of many non-English papers cited in this review are available at the home page of this author . The book on scurvy by Hess is available in a digitized format .
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Marginally Low Vitamin C Status Might Lead To Benefits Of Supplementation
It seems evident that any effects of vitamin C supplementation may be more prominent when the baseline vitamin C level is particularly low. As noted above, a profound vitamin C deficiency was associated with pneumonia in the early literature. It seems plausible that less severe vitamin C deficiency, which may be called marginal vitamin C deficiency, can also be associated with increased risk and severity of infections, although the effects may be less pronounced than those caused by scurvy.
Low vitamin C levels are not just of historical relevance. Cases of scurvy in hospitals have been described in several recent case reports . One survey estimated that about 10% of hospitalized elderly patients had scurvy . Surveys have also shown that plasma vitamin C levels below 11 µmol/L were found for 14% of males and 10% of females in the USA, 19% of males and 13% of females in India, 40% of elderly people living in institutions in the UK, 23% of children and 39% of women in Mexico, and 79%93% of men in Western Russia. Moreover, 45% of a cohort of pregnant women in rural India had plasma vitamin C levels below 4 µmol/L and the mean plasma vitamin C level fell to 10 µmol/L in a cohort of pregnant or lactating women in Gambian villages in the rainy season .
Impair The Effectiveness Of Niacin
Evidence suggests that taking vitamin C supplements may impair the bodys ability to increase high density lipoprotein cholesterol in people taking the combination drug niacin-simvastatin. This drug combines the vitamin niacin with the statin simvastatin , and people take it to treat high cholesterol.
Doctors consider HDL cholesterol the good cholesterol because it reduces the amount of harmful cholesterol in the blood.
If a person takes vitamin C supplements and niacin-simvastatin, they should talk to their doctor about ways to make each more effective. Doctors do not know whether vitamin C also affects the ability of other medicines similar to Zocor.
A persons body cannot make vitamin C, so people need to eat enough foods that contain vitamin C to meet their daily needs. If someone is at risk of a vitamin C deficiency, they can take vitamin C supplements.
The advise aiming for the following RDA of vitamin C each day:
|90 mg||75 mg|
People who smoke should take 35 mg more vitamin C per day than those who do not smoke.
During pregnancy or when breastfeeding, women should get the following levels of vitamin C per day:
- 1418 years: 80 mg during pregnancy and 115 mg when breastfeeding
- 19 years and older: 85 mg during pregnancy and 120 mg when breastfeeding
There is not enough research to suggest an RDA for vitamin C in those younger than 1 year of age. As a result, the ODS provide an adequate intake, which is the amount that is likely to be sufficient:
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What To Expect At The Emergency Room
Take the container with you to the hospital, if possible.
The health care provider will measure and monitor the persons vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated. The person may receive:
- Activated charcoal, depending on the vitamin taken
- Blood and urine tests
- Breathing support, including oxygen, tube through the mouth into the lungs, and breathing machine
- Intravenous fluids through a vein
- Medicines to remove iron from the body, if needed
- Blood transfusions , if needed
In severe cases, the person may be admitted to the hospital.
Implications Of The Animal Studies
Many of the studies on vitamin C and infections summarized in are old. However, it is unlikely that administering a specified dose of pure vitamin C and evaluating clinical outcomes of infections, such as mortality, will have changed meaningfully since those early days. Furthermore, 60 studies were published in the 1990s or later, and half of these later reports also found significant benefits of vitamin C on at least one infectious disease outcome.
The studies on guinea pigs are most interesting since that species is dependent on dietary vitamin C as are humans. Infections in guinea pigs against which vitamin C was significantly beneficial included Mycobacterium tuberculosis, –hemolytic streptococci, Fusobacterium necrophorum, diphtheria toxin, Entamoeba histolytica, Trypanosoma brucei, and Candica albicans .
Some of the 148 studies in were small and did not have sufficient statistical power to test whether vitamin C and control groups might differ. However, this problem cannot explain the large number of reported significant benefits. In contrast, inclusion of studies with a low statistical power biases the findings towards the opposite direction, leading to false negative findings.
Mortality and severity of infections in animals are definitive outcomes. In this respect, the animal studies with actual infections are much more relevant to humans than studies on laboratory determinations of the human immune system.
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Is Vitamin C Bad For You
The most concerning pro-oxidant effect happens in the presence of free transition metals. Now these metals are something all of us have in our bodies, so its impossible to avoid 100%. Ascorbic acid is one of the most researched nutrients and to date, the overwhelming consensus is that its good for you even when this is factored in.
Plus unlike dogs and cats, human are unique mammals in that we dont internally create this vitamin. We literally dont have a choice we need to get it from dietary sources.
What we do have a choice on though is how much we consume. We know how much is needed to avoid scurvy and deficiency symptoms and its the amount beyond that where the question mark remains is more necessarily better?
A recent scientific review of its antioxidant and pro-oxidant activity in oral health sums up the current mindset quite well:
The data validates the role of Vitamin C as an antioxidant under physiologic conditions exhibiting a cross over role as a pro-oxidant in pathological conditions. Further studies are required to substantiate its pro-oxidant activity to draw concrete conclusions.
While that review was specific to oral health, the scientists factored in generalized pro-oxidant vs. antioxidant research, too.
Misconceptions And Prejudices About Vitamin C And Infections
In the first half of the 20th century, a large number of papers were published in the medical literature on vitamin C and infections and several physicians were enthusiastic about vitamin C. The topic was not dismissed because of large-scale controlled trials showing that vitamin C was ineffective. Instead, many rather large trials found benefits of vitamin C. There seem to be four particular reasons why the interest in vitamin C and infections disappeared.
The belief that vitamin C is ineffective has been widely spread. For example, a survey of general practitioners in the Netherlands revealed that 47% of respondents considered that homeopathy is efficacious for the treatment of the common cold, whereas only 20% of those respondents considered that vitamin C was . Prejudices against vitamin C are not limited to the common cold. Richards compared the attitudes and arguments of physicians to three putative cancer medicines, 5-fluorouracil, interferon and vitamin C, and documented unambiguous bias against vitamin C . Goodwin and Tangum gave several examples to support the conclusion that there has been a systematic bias against the concept that vitamins may yield benefits in levels higher than the minimum needed to avoid the classic deficiency diseases .
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Deffects Of Hypervitaminosis A
The effects of high doses of vitamin A on humans and experimental animals have been reviewed by Clark . Naturally occurring hypervitaminosis A may result from consumption of liver from the polar bear or bearded seal. Most reports are of natural or accidental hypervitaminosis in man or experimental studies in the rat, dog, cat, pig, calf, and chicken. Few studies have dealt with effects of hypervitaminosis A on the guinea pig. Wolbach reported degenerative changes in the cartilagenous epiphyseal plates of long bones from guinea pigs that were fed excessive amounts of vitamin A. These changes were similar to those reported in the rat and dog. Besides rapid maturation of epiphyseal cartilage, there was increased bone resorption which interfered with normal remodeling.
Robens has described the teratogenic effects of hypervitaminosis A in the hamster and guinea pig. Administration of a single oral dose of 200,000 USP units/kg to pregnant guinea pigs during organogenesis produced soft tissue and skeletal anomalies in the offspring. The most frequent defects recorded were agnathia, synotia, malpositioning of teeth, and microstomia. Administration of the same dose between day 17 and 20 frequently produced changes in the tibias and fibulas. Fetal growth was not affected by vitamin A excess. It is not clear what mechanisms explain the fetal malformations produced by an overdose of vitamin A organogenesis.
D.D. Thomas, D.W. Steenkamp, in, 2016
Can We Overdose On Vitamin C
Yes, you can. Many people assume that since vitamin C is a water-soluble vitamin, you can never take too much of it. Their reasoning is that youll essentially just pee out any excess. Although this is true, if you take more than the amount your body is able to excrete, it will not go over well. Side effects include nausea and diarrhea two things any sane person should avoid.
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Hypervitaminosis: A Global Concern
Alta Bates Summit Medical CenterBerkeley, California
U.S. Pharm. 2021 46:47-50.
Vitamins are essential in regulating various metabolic and biologic activities in the human body. However, overconsumption and prolonged use of pharmaceutical forms of both water-soluble and fat-soluble vitamins may lead to accumulation and toxicity. In cases of acute poisoning resulting from vitamin supplements or drugs, emergency assistance is required to detoxify the effects and to restore the function of the bodys organs. To manage any type of hypervitaminosis, proper diagnosis is essential in expediting elimination of the supplement from the body.1,2
Generally, vitamins and dietary supplements are taken to improve health or well-being. However, they are not necessarily safe for everyone. Like regular drugs, supplements with active ingredients provide a physiologic or pharmacologic effect that can also cause adverse effects in susceptible individuals. Therefore, attention to adverse effects and potential interactions is necessary to avoid serious medical problems. Medical providers are aware that a large percentage of the population takes dietary supplements, and they request information from patients about supplement intake to provide optimal medical care.2
Biology Relevant To The Effects Of Vitamin C On Infections
Evidence-based medicine emphasizes that in the evaluation of treatments researchers should focus primarily on clinically relevant outcomes, and little weight should be put on biological explanations. Therefore, this review focuses on infections and not on the immune system. Immune system effects are surrogates for clinical effects and there are numerous cases when surrogates had poor correlations with clinically relevant outcomes . Nevertheless, biology provides a useful background when we consider the plausibility of vitamin C to influence infections.
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Vitamin C May Protect Against Stress Caused By Cold And Hot Environments
Studies in animals and humans have indicated that vitamin C may protect against stress caused by cold and hot environments . Some common cold studies with positive results investigated physically active participants in cold environments and other studies investigated marathon runners in South Africa . Therefore, the effects of vitamin C in the protection against cold or heat stress might also be relevant when explaining the benefits in those studies.
Other Ways To Boost Your Immune System
Despite what supplement makers have led you to believe, there is no scientific evidence that vitamin C directly prevents colds and flu viruses. In fact, the National Center for Complementary and Alternative Medicine says that taking these costly supplements only slightly minimizes the duration of a cold. Furthermore, taking vitamin C after getting sick doesnt help at all.
Youre better off saving your money and making sure you get enough vitamin C in your daily diet instead.
As with other preventive health measures, the best way to ward off cold and flu viruses is to take care of yourself. You can accomplish this by:
- getting adequate sleep every night
- exercising regularly
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