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Is Vitamin C Good For Colds

How The Review Was Done

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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.

Should I Take Vitamin C Supplements

As you can see from the above, its not hard to get your daily dose of vitamin C through your diet. In addition to the foods already listed, vitamin C is also found in grapefruit, blackcurrants, blueberries, melon, spinach, peppers, tomatoes, brussels sprouts and even potatoes.

Of course, you may still struggle to get enough through your diet alone, and might want to take vitamin C supplements. According to the NHS, takingup to 1,000 milligrams of vitamin C supplements each day is unlikely to cause harm. Taking more than this might cause unpleasant symptoms like stomach pain and diarrhoea.

In general, its a good idea to speak to your GP before you start taking supplements, especially if you think you might have a vitamin C deficiency .

How Much Vitamin C Should Adults And Children Take

The recommended daily amount of vitamin C for adults is 90 mg for men, 75 mg for women, and up to 120 mg for people who are pregnant or nursing. However, certain medical conditions may require that you take much higher doses .

Children have lower vitamin C requirements, ranging from 2575 mg per day, depending on their age. However, healthcare professionals generally do not advise giving children a vitamin C supplement unless their pediatrician has recommended it.

Note that the Tolerable Upper Intake Level for vitamin C for men and women ages 19 years and older is 2,000 mg. That said, some people experience side effects with frequent and prolonged intake of 1,000 mg per day .

Meanwhile, the UL for children ranges from 4001,800 mg, depending on their age. Daily intakes at or below these amounts are unlikely to result in any negative health effects .

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Vitamin C Can Help You Get Over A Cold Faster

So if you are healthy, feeling well, and are just trying to prevent catching the cold, vitamin C can’t do much for you. But if you’re already sick, it’s a different story.

“It can shorten the length of a cold and decreases the severity of the illness,” Sevilla says.

But if you want to cut down your cold time, you’ll likely need more than the recommended dietary amount. The Food and Nutrition Board at the National Academies recommends 75 to 90 mg of vitamin C a day for adults. To fight that cold, you’ll need more than double that amount.

In one 2013 review, from the Cochrane Database of Systematic Reviews, researchers found evidence from multiple trials that participants who took at least 200 mg of vitamin C regularly over the course of a trial got over their cold faster than participants who took a placebo. Adults who took vitamin C saw an 8% reduction in the duration of their cold compared to the placebo group. And children had an even larger reduction by 14%.

Plus, the review also found that, as Sevilla says, vitamin C can also reduce the severity of the cold once you have one.

You can easily get 200 mg of vitamin C from eating a small papaya, which has about 96 mg, and a cup of sliced red bell peppers, which racks up 117 mg. But a faster way to get an even larger dose is from powders or supplements, which can give you as much as 1,000 mg of vitamin C in a single packet that’s 1,111% to 1,333% of your recommended daily allowance.

Does Taking Vitamin C In High Doses At The Onset Of A Cold Have A Therapeutic Effect

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Selection criteria: Randomised and non-randomised trials of vitamin C taken to prevent or treat the common cold. Data collection and analysis: Two reviewers independently extracted data and assessed trial quality. The quality of the included trials was variable. Vitamin C in doses as high as one gram daily for several winter months, had no consistent beneficial effect on incidence of the common cold. For both preventive and therapeutic trials, there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms. The weighted difference across all of the studies revealed a reduction of a little less than half a symptom day per cold episode, representing an 8% to 9% reduction in symptom days. However in trials that tested vitamin C after cold symptoms occurred, there was some evidence that a large dose produced greater benefits than lower doses.

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Vitamin C Does Not Prevent Colds

“Nobel prize winner Dr. Linus Pauling famously claimed in the 1970s that high doses of vitamin C prevented the common cold,” says Mike Sevilla, a family physician in Salem, Ohio.

But Pauling had little evidence to back his claim. The foundations of his argument came from a single study of a sample of children in the Swiss Alps, which he then generalized to the overall population.

Turns out he overgeneralized, and numerous studies have since disproved Pauling’s claim.

“Unfortunately, follow-up research has shown that vitamin C does not prevent the common cold,” Sevilla says. Yet this misconception continues to live on.

“In my family practice office, I see patients from a variety of cultures and backgrounds and the use of vitamin C for the common cold is well known across all of them,” Sevilla says.

Can Vitamin C Prevent Or Treat Cold Symptoms

Vitamin C has been studied for many years as a possible treatment for colds, or as a way to help prevent colds. But findings have been inconsistent. Overall, experts have found little to no benefit from vitamin C for preventing or treating the common cold.

In a July 2007 study, researchers wanted to discover whether taking 200 milligrams or more of vitamin C daily could reduce the frequency, duration, or severity of a cold. After reviewing 60 years of clinical research, they found that when taken after a cold starts, vitamin C supplements do not make a cold shorter or less severe. When taken daily, vitamin C very slightly shortened cold duration — by 8% in adults and by 14% in children.

In 2010, researchers looked at all studies and found that taking vitamin C every day did not prevent the number of colds that a person got. In some cases, it made symptoms improve.

The results were different for people who were in very good physical condition, such as marathon runners. People like that who took vitamin C every day cut their risk of catching a cold in half.

So what does all this mean?


According to this research, the average adult who suffers with a cold for 12 days a year would still suffer for about 11 days a year if that person took a high dose of vitamin C every day during that year.

For the average child who suffers about 28 days of cold illness a year, taking daily high-dose vitamin C would still likely mean about 24 days of cold illness.

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Are There Side Effects Or Risks To Consider

Taking an increased amount of vitamin C for a short period of time is generally considered safe.

Vitamin Cs tolerable upper intake level is 2,000 mg per day for adults ages 19 and older.

Emergen-C packets contain 1,000 mg each. This means that you can probably still consume vitamin C through your diet without hitting the max UL.

Consuming 2,000 mg or more may cause:

  • abdominal pain

Emergen-C contains far lower levels of all of the other vitamins and minerals on its ingredient list. No other ingredient comes this close to the respective UL for adults.

Talk to a doctor or other healthcare provider before use if you:

  • take prescription medication

Objectives: The Objective Of This Review Was To Answer The Following Two Questions: Does Regular High Dosage Supplementation With Vitamin C Reduce The Incidence Of Colds

Should You Take Vitamin C Supplements For a Cold? | Dr. Ian Smith Answers

Search strategy: This review currently deals only with published trials from two previously published reviews by Kleijnen 1989 and Hemila 1992. Selection criteria: Randomised and non-randomised trials of vitamin C taken to prevent or treat the common cold. Data collection and analysis: Two reviewers independently extracted data and assessed trial quality. Vitamin C in doses as high as one gram daily for several winter months, had no consistent beneficial effect on incidence of the common cold. For both preventive and therapeutic trials, there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms. However in trials that tested vitamin C after cold symptoms occurred, there was some evidence that a large dose produced greater benefits than lower doses.

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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.

The Side Effects Of Too Much Vitamin C

If you’re planning to take that much vitamin C every day for an extended period, it merits a talk with a doctor.

Sevilla says that taking more than 2,000 mg of vitamin C daily has been known to cause GI effects like nausea and abdominal pain. It’s primarily because of those issues that the tolerable upper intake level the max you should take unless under the direction of a doctor is 2,000 mg for adults.

And if you’re debating between a food and a supplement, Sevilla recommends sticking with food as your source of vitamin C, if you can manage it.

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Sip Hot Broths And Beverages

It turns out your mother was right. Hot chicken soup and tea with honey and lemon provide relief when you are sick.Inhaling warm vapors raises the temperature of the respiratory passages, which loosens thickened nasal mucous. In addition, the fluid in soup, tea, and other beverages replaces water lost through increased mucous and sweat production.

Neurodegenerative And Mental Health Disorders


Vitamin C’s antioxidant activity may play a role in brain heath.

Research suggests regular dietary intake plus supplements may protect you from neurodegeneration related to aging and diseases such as:

Studies suggest vitamin C deficiency may contribute to the development of these mental and neurodegenerative conditions and that supplementation may help alleviate symptoms. However, this work is preliminary and more research is needed.

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Too Much Of A Good Thing

While there are no product-specific studies testing Airborne and Emergen-Cs effectiveness in preventing and treating the common cold, research that looks at ingredients like vitamin C and zinc can give us some insight into how well the products work.

A 2013 research review showed that vitamin C is water-soluble, so when taken in excess, it at least wont build up in your tissues like fat-soluble vitamins can.

As weve mentioned, the research on vitamin C is mixed, but according to the National Institutes of Health, many health professionals maintain that its not an effective treatment.

Research on zinc is positive but still pretty inconclusive. A 2011 research review found some evidence that taking a zinc supplement soon after the onset of symptoms could significantly reduce the duration and severity.

Researchers are still working on how much, how often, and when to take it for max effect.

There are still a few things to consider before overdoing it on the fizzy drinks. For example, a 2013 study showed that too much vitamin C can cause diarrhea, nausea, stomach cramps, and kidney stones.

The National Institutes of Health suggest that adults consume no more than 2,000 milligrams of vitamin C each day.

Similarly, too much vitamin A might do more harm than good. According to the National Institutes of Health, excess doses of more than 3,000 IU per day can cause dizziness, nausea, headaches, coma, and death.

What Causes A Vitamin C Deficiency

A deficiency occurs either from insufficient nutrient intake in the diet or increased losses due to poor absorption.

People who don’t consume various foods, mainly fruits and vegetables, are at greater risk of vitamin C deficiency. Smokers have a higher requirement for vitamin C, so smoking may also be a risk factor.

Additionally, people with malabsorption disorders may become deficient because they can’t absorb enough vitamin C.

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Vitamin C Helps To Lower The Chances Of Catching A Cold

A balanced vitamin C level contributes to the healthy function of the immune system. Once the cold viruses have reached our mucous membranes, vitamin C becomes active in various places. It induces the formation of white blood cells, adheres to free radicals, neutralizing them and regenerating more of the body’s own antioxidants. In this way, it keeps our immune system going and reduces oxidative stress. When a cold starts, the vitamin C level occasionally falls drastically owing to the increased expenditure. If this happens, it is advisable to take high doses of vitamin C quickly to support our bodys defense system that it is not brought down to its knees.

As little as two glasses of freshly squeezed orange juice a day help us to have a healthy immune system. This was shown by some studies, in which a balanced vitamin C level could shorten the duration of a cold somewhat and alleviated symptoms. If you notice the first signs of a cold, it is therefore a good idea to fill up the vitamin C reservoir immediately and not to give up until you have hopefully recovered quickly from the cold.

Here Are Some Myths And Facts About Immune

Can Vitamin C and Zinc Help Cure Colds?

Myth: Vitamin C prevents illness.

Turning to large doses of vitamin C in the winter to avoid getting sick doesn’t work. However, vitamin C may shorten the duration of a cold once you’re already under the weather. Vitamin C is also an antioxidant, and those anti-inflammatory properties may reduce swollen sinuses.

Myth: Zinc boosts your immune system.

Much like vitamin C, there’s not enough evidence to support taking extra zinc to keep sickness at bay. Meeting daily zinc requirements is important for a healthy immune system, but exceeding these requirements can be toxic. In 2009, the Food and Drug Administration warned consumers to stay away from zinc nasal sprays after studies found they could damage the sense of smell.

Fact: Chicken soup is a cure-all.

The healing benefits of chicken soup are numerous, according to the National Institutes of Health. Not only is grandma’s home remedy heartwarming, but it also has properties that fight inflammation, promote hydration and get mucus flowing.

Myth: Dairy increases mucus production.

Some swear that milk and other dairy products make a phlegmy illness worse, but there’s no science behind it. Most studies have found no relationship between eating dairy and increased mucus production.

Choose immune-boosting nutrients

These nutrients play a role in boosting the immune system:

Keep the immune system strong all year long

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What Are The Side Effects Of Vitamin C

Vitamin C is generally considered safe, but high doses can cause side effects. These may include:

Higher doses are more likely to lead to side effects. Doses over 2,000 milligrams a day may increase the risk of diarrhea and kidney stones. If you have a history of kidney stones, taking more than 1,000 milligrams a day may increase your chances of having more.

Cancer Treatment And Prevention

A lot of research has investigated the role of antioxidants, including vitamin C, in cancer care and prevention. However, the results have yielded inconsistent results.

Most studies have found that vitamin C supplementation, either on its own or in combination with other supplements, cannot prevent or treat cancer.

Some studies have shown that when used in supportive care, high-dose intravenous vitamin C can improve quality of life and reduce the side effects of standard cancer treatments.

When it comes to cancer, it’s become clear that antioxidants aren’t all good or all bad. Studies have also shown that antioxidants may:

  • Help cancerous or pre-cancerous cells survive
  • Possibly make some cancer treatments less effective

Some healthcare providers recommend eating more antioxidant-containing fruits and vegetables, as people with diets rich in vitamin C may have a lower risk of getting certain types of cancer. However, it’s important to remember that no one food will prevent cancer. Moreover, vitamin C supplements themselves do not appear to prevent cancer. Eating a well-balanced diet in general, including antioxidants, is beneficial for your overall health.

Future studies are needed to establish the role of antioxidants like vitamin C in cancer. Talk to your oncologist before starting any supplements during cancer treatment.

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