How The Review Was Done
This summary is based on a review of 63 randomized controlled trials with 11,306 adults and children. 60 trials were based in the community and 3 in the lab. Most of the trials focused on regular supplements of vitamin C to prevent a person from getting a cold. 10 trials focused on the use of vitamin C as a treatment once the natural cold symptoms had started.
How Much Vitamin C Should You Take
Vitamin C is a water-soluble nutrient with many vital functions in your body.
It helps strengthen your immune system, aids collagen production and wound healing, and acts as an antioxidant to protect your cells from free radical damage .
Vitamin C is also known as L-ascorbic acid, or simply ascorbic acid.
Unlike other animals, humans cannot synthesize vitamin C on their own. Therefore, you must get enough of it from foods or supplements to maintain good health (
Vitamin C For Preventing And Treating The Common Cold
The common cold is a major cause of visits to a doctor in high-income countries and of absenteeism from work and school. There are over 200 viruses which can cause the common cold symptoms including runny nose, congestion, sneezing, sore throat, cough, and sometimes headache, fever and red eyes. Symptoms vary from person to person and cold to cold. Since the common cold is usually caused by one of the respiratory viruses, antibiotics are useless and therefore other potential treatment options are of substantial public health interest.
Vitamin C has been proposed for treating respiratory infections since it was isolated in the 1930s. It became particularly popular in the 1970s when Nobel laureate Linus Pauling concluded from earlier placebo-controlled trials that vitamin C would prevent and alleviate the common cold. Over two dozen new trials were undertaken thereafter. Vitamin C has been widely sold and used as a preventive and therapeutic agent.
Vitamin C for preventing and treating the common cold has been a subject of controversy for 70 years.
To find out whether vitamin C reduces the incidence, the duration or severity of the common cold when used either as a continuous regular supplementation every day or as a therapy at the onset of cold symptoms.
We excluded trials which used less than 0.2 g per day of vitamin C and trials without a placebo comparison. We restricted our review to placebo-controlled trials.
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Cold And Flu: Prevention And Natural Therapies
Its important to strengthen and maintain a healthy immune system all year round so that your body can adequately fight influenza viruses and the viruses that cause the common cold. Though many people believe its not possible to ward off a cold or the flu, with the exception of the flu vaccine, the truth is we actually have a great deal of control over our health during the cold and flu season. Scientific studies support the effectiveness of cold and flu prevention strategies and natural therapies. By following these measures, we can exert some control over whether we get sick, the duration of recovery time, and the severity of symptoms.
8 Preventive Strategies To help you maintain a healthy immune system, incorporate these 8 strategies into your daily routine:
What The Researchers Found
When vitamin C was used as a regular supplement to prevent a person from getting a cold , the duration of colds was reduced by 8% in adults and 14% in children. In children, higher doses shortened colds by 18%. The severity of colds was also reduced by regular vitamin C supplements. Vitamin C did not reduce the number of people who caught colds. While these results were consistent across studies, their effect was small.
The use of vitamin C as treatment did not reduce the duration and severity of the cold when compared to people who did not receive it.
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How Does It Affect Immunity
Vitamin C affects your immune health in several ways. Its antioxidant activity can decrease inflammation, which may help improve your immune function .
Vitamin C also keeps your skin healthy by boosting collagen production, helping the skin serve as a functional barrier to keep harmful compounds from entering your body. Vitamin C in the skin can also promote wound healing .
The vitamin also boosts the activity of phagocytes, immune cells that can swallow harmful bacteria and other particles .
In addition, it promotes the growth and spread of lymphocytes, a type of immune cell that increases your circulating antibodies, proteins that can attack foreign or harmful substances in your blood .
In studies of its effectiveness against viruses that cause the common cold, vitamin C doesnt appear to make you any less likely to get a cold but it may help you get over a cold faster and make the symptoms less severe .
Theres also some evidence from animal research and case studies in humans that high dose or IV vitamin C can reduce lung inflammation in severe respiratory illnesses caused by H1N1 or other viruses .
However, these doses were far above the DV, and theres not enough research to support the use of high dose vitamin C for lung inflammation at this time. You shouldnt take high doses of vitamin C supplements even orally because they can cause side effects like diarrhea .
Does Vitamin C Help With Colds
In the 1970s, Linus Pauling, a double Nobel laureate and self-proclaimed champion of vitamin C, promoted megadoses of the vitamin. He recommended the equivalent of 12 to 24 oranges a day to prevent colds and some chronic diseases, such as cancer and heart disease. And on one aspect, he was right: Science does support daily intake of vitamin C because, as a water-soluble vitamin, the body doesnt store it easily. But high doses of vitamin C dont prevent disease.
No studies have conclusively shown vitamin C has any benefit in preventing illness, especially the common cold. It does play an important role in boosting the immune system, but most people in the United States are not vitamin C-deficient, so taking extra vitamin C doesnt necessarily boost the immune system, says Oladimeji Oki, M.D., a family physician at the Montefiore Medical Center and a professor of family and social medicine at Albert Einstein College of Medicine. There are some exceptions to this rule, he says. We tend to see vitamin C deficiency in people with little access to food or severe poverty, people who are institutionalized and not eating well, or those who have an aversion to most if not all foods and vegetables, such as some children with autism.
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Continuous Supplementation During The Winter Months
Researchers have demonstrated that vitamin C supplementation is more effective as a preventive measure rather than as a cure for a cold.
Therefore, supplementation should begin before you catch a cold and not after. But is this belief supported by hard evidence? The answer is yes.
In a study published in 2002 in the journal, Advances in Therapy, 168 volunteers were randomly assigned to take either placebo or a vitamin C supplement over a 60-day period spanning the length of the winter months.
The results of the study showed that group receiving the vitamin C supplement had fewer incidences of cold and fewer days of severe symptoms than the placebo group.
This result shows that vitamin C supplementation during the winter reduced the risk of catching a cold and improved the speed of recovery. Therefore, the use of vitamin C supplements right from the beginning of the cold and flu season to the end may be justified as a preventive measure to avoid coming down with a cold or the flu.
How To Protect Yourself
There is no effective treatment for stomach flu. Drugs can’t cure stomach flu, and antibiotics cannot help because the condition is caused by a virus. So prevention is the best medicine.
The best way to prevent being infected by someone else is by practicing proper hand hygiene. Wash your hands thoroughly with soap and water, especially before eating or after using the toilet and always before preparing or handling food. Practice food safety by carefully washing fruits and vegetables.
âRead more:â How to Avoid Catching a Stomach Virus
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Looking For Information On Coronavirus
Please see our evidence-based page on coronavirus / COVID-19.
Colds and the flu are caused by viruses that travel from person to person. Although you fend off infections year round, you may be more vulnerable during the colder months: the ambient cold may weaken your immune system, according to preliminary human and animal evidence, and if it makes you spend more time inside with other people, it also gives you more opportunities to trade viruses and microbes.Unfortunately, even if you follow these best practices, you can still get unlucky and catch a cold or contract the flu. This is why, once winter hits, one of the most popular questions we get is:among the manysupplements used to ward off an infection or lessen its symptoms, are there any that work?
The answer is a tentative yes. In this article, well review four supplements whose benefits are backed by and four whose benefits are backed by only .
Can You Prevent The Stomach Flu With Vitamin C
Maintaining the recommended levels of vitamin C is important for optimal immune function to help your body ward off colds and flu. Although both the common cold and stomach flu have initial, similar symptoms, they are caused by different viruses. Vitamin C has been shown to have some benefits against the cold virus, but these do not apply to stomach flu. However, there are things you can do to minimize your risks or shorten the length of the illness.
No clear evidence shows any direct positive effect of vitamin C on the stomach flu virus, other than its ability to boost your immune system.
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So Whats The Best Approach To Fight Colds
Vitamin C and zinc are just two of many remedies touted as cures for the common cold. Some claim that elderberry can help. Others say to try putting garlic up your nose. Theres been a push for fire cider and echinacea flower, too.
So, why do folks sometimes think they feel better after trying one of these tactics? These cold products might produce a placebo effect, where you essentially trick yourself into believing something worked.
Bottom line, though? When youre sick, says Dr. Ford, the best medicine still seems to be time, fluids and rest.
Taking Megadoses Of Vitamins And Other Supplements Doesnt Do Anything To Prevent Or Shorten Illness
by Rebecca Kern, AARP Bulletin, February 11, 2009
Myth: Taking extra vitamin C helps prevent colds, the flu and other winter maladies.
Facts: Loading up on megadoses of vitamin Csay, between 1,000 and 5,000 milligrams doesnt do anything to prevent illness, says Adriane Fugh-Berman, M.D., an associate professor in the Department of Physiology and Biophysics at Georgetown University. An infusion of vitamin C also isnt likely to make the duration of a cold any shorter, according to Gigi El-Bayoumi, M.D., associate professor of medicine at the George Washington School of Medicine and Health Sciences. During trials, only one in 10 people taking vitamin C found their colds cleared up faster. Vitamin C consumption often has a psychological effect, El-Bayoumi adds: People feel better because they are doing something about their illness.
Vitamin C is water-soluble and not considered harmful if you take more than the daily recommended dose of 100 mg, as long as you dont exceed 2000 mg, says Larry Walker, Ph.D., director of the National Center for Natural Products Research at the University of Mississippi. If you take more vitamins than the body requires, they will simply be excreted in urine.
No drugs yet treat the viral infection that causes the common cold, says Walker. Over-the-counter drugs treat only the colds symptoms.
Rebecca Kern is a writer based in Washington, D.C.
AARP is a nonprofit, nonpartisan organization that empowers people to choose how they live as they age.
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Is Vitamin C Safe To Take
In general, vitamin C won’t harm you if you get it by eating food like fruits and veggies. For most people, it’s also OK if you take supplements in the recommended amount.
The RDA, or recommended daily allowance, is 90 milligrams for men and 75 milligrams for women. High doses of vitamin C may cause kidney stones, nausea, and diarrhea.
If you’re unsure about taking vitamin C for colds, talk to your health care provider.
Take Vitamin C 1 Gram An Hour
At the first signs of a cold take 2 grams immediately, then 1 gram an hour until the cold is gone . You could take 2 grams every two hours, or even 3 grams every three hours . The point is to keep drip feeding enough vitamin C into your bloodstream to keep the level consistently high. Vitamin C is in and out of the body in four to six hours. In case youre worried vitamin C, in high doses, has been well proven to be non-toxic in both adults and children even if taken over many years.
However, you do get loose bowels. The best dose is the level just below bowel tolerance. Everyone is different in this respect to its best to just try it and find your own way. There is no harm in having high doses for a few days. When all symptoms are gone dont suddenly cut it out completely. Have, for example, 4 grams spread out during the next day, then reduce to 2 grams a day, one in the morning and one in the afternoon.
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Do You Need To Supplement
Currently, no evidence supports the use of oral vitamin C supplements to prevent COVID-19.
Vitamin C may help shorten the duration and severity of colds caused by other viruses, but this is no guarantee that it will have the same effect on the coronavirus that causes COVID-19.
Additionally, vitamin C is a water-soluble vitamin. It dissolves in water, meaning that excess amounts arent stored in your body but instead eliminated through your urine. Taking more vitamin C does not mean that your body is absorbing more .
High dose vitamin C supplements may even cause diarrhea, as they can signal your body to pull water out of the cells and into your digestive tract .
Moreover, although high dose vitamin C appears promising for COVID-19 treatment, these doses were exceptionally high and given via IV not taken orally. Additionally, it was only given in cases severe enough to require hospitalization.
Your best bet is to eat a diet thats full of a variety of fruits and vegetables, which naturally provide all the vitamin C a healthy person needs along with many other nutrients and antioxidants.
Vitamin C And Zinc For Flu
Now that you know all about vitamin C, you must understand the role of zinc as well. Some nutrients play critical roles in maintaining the integrity and function of the immune system. Among these elements, zinc, and vitamins C stands out for their roles in strengthening the immune system. Nutrients that can help the immune system to reduce the risk of severe progression become essential regarding the influenza virus.
Over-the-counter supplements such as zinc gluconate and ascorbic acid commonly treat viral illnesses. Zinc has been shown to improve the ability of immune cells to fight infection, and ascorbic acid is an antioxidant that may play a role in the immune response.
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How Much Vitamin C Do I Need To Stay Healthy
The NHS recommends that adults aged between 19 and 64 should have 40 milligrams of vitamin C each day.
To give you an idea of how much that is, heres the vitamin C content of some popular fruits and vegetables, according to Diabetes.co.uk:
- 100g of orange contains 52mg
- 100g of strawberries contains 57mg
- 100g of kiwi fruit contains 59mg
- 100g of broccoli contains 79mg
- 100g of red cabbage contains 55mg
Generally, its best to eat these kinds of foods raw, as cooking reduces the vitamin C content by about one third. This is why oranges are a popular way of getting your daily vitamin C. Read our guide to discover more foods high in vitamin C.
Can Vitamin C Help Cold
Over 60 years of research into the benefits of vitamin C for preventing or treating vitamin C has only yielded inconsistent results. This means that there are well-designed studies that have found little use for vitamin C in the prevention of cold as there are good studies that concluded that the vitamin helped.
A summary of the results of these studies can be obtained from a review done by the Cochrane Collaboration on the subject.
According to the Cochrane review, it appears that vitamin C is not very useful in the treatment of a cold.
The evidence shows that after the onset of cold symptoms, vitamin C supplementation is useless. It does not reduce the duration of the cold or its severity.
When taken daily, studies show that vitamin C may shorten the duration of a cold by 8% in adults and 14% in children.
While these may seem like small effects on cold, its contribution can definitely reduce how long sufferers stay sick.
The best benefit for vitamin C supplementation in the prevention of cold is for those who partake in high-intensity exercises. Vitamin C can reduce the risk of coming down with a cold by 50% among people exposed to extreme conditions.
Therefore, regular vitamin C supplementation may not be the cure-all it is marketed to be but it can still cut your risk of catching a cold and especially provide significant protection if you are working under conditions of physical stress.
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