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Vitamin C in a nutshell:
Vitamin C is the “scurvy vitamin” we learnt about at school. It is an antioxidant that is responsible for mopping up free radicals produced when glucose is broken down for energy. Vitamin C also has many other roles in the body including the formation of the structural protein collagen, heart and brain health, feel good factor and much more.  Read more about these below.

Antioxidants & Free Radicals Explained

Best source of vitamin C for Juicers:
Green chilli peppers, kale, parsley, broccoli, sprouts, water cress, cauliflower, cabbage, strawberries, papaya, spinach, citrus fruit, mangoes, asparagus, cantaloupes, kiwi fruit, bell peppers.

Vitamin C is the vitamin we all know—but it's a vitamin that has both surprising applications and surprising limitations. This article will tell you everything you need to know about how to use, and how not to use, vitamin C for optimum health.

Alternative names:

Vitamin C; ascorbic acid.

What Is Vitamin C?

Vitamin C is a water-soluble nutrient that was regarded as a wonder drug for well over 100 years before scientists were able to identify its chemical structure.

A vitamin deficiency syndrome known as scurvy was the scourge of ocean travel for hundreds of years. At first the gums would bleed. The the teeth would come loose and fall out. There would be bleeding from the eyes and nose, and fatigue, followed by a painful inexplicable death, usually starting about two months after leaving port.

Prevention methods for scurvy seem to have been discovered and lost over and over again in the history of marine navigation all over the world. Egyptian, Dutch, and Japanese explorers seem to have discovered them, only for them to be forgotten a generation later. Thousands of years of nautical exploration passed before any ship captain made a lasting record of treatment for this disease.

In the western world, scurvy was first found to be curable in 1536, during the second voyage of ships captained by Jacques Cartier in the early exploration of the coast of Canada. Cartier's crew was near death when he happened on a tree he later called arborvitae, the “tree of life.” Making a tea out of the leaves of this tree resuscitated his crew and allowed them to complete their mapping of the eastern shores of Canada and the St. Lawrence river to the modern day location of Montréal.

Modern scientists now know that the healing ingredients in arborvitae included vitamin C with a variety of naturally occurring antioxidants and all the essential amino acids. That the critical ingredient of the mixture was what we now call vitamin C was not known until nearly 400 years later, thanks to the work of a Hungarian (later American) scientist named Albert Szent-György. At first, however, Szent-György had greater interest in a substance he called “vitamin P.”

The chemical we now call vitamin C, ascorbic acid, had been isolated from the paprika used to make goulash by another scientist named Walter Norman Haworth. It was assumed that this new vitamin would be the complete and immediate fix for scurvy—but it wasn't. It turned out that paprika used to make goulash helped scurvy but vitamin C capsules did not.

Szent-György thought the missing ingredient might be some plant chemical in paprika he tentatively called vitamin P, or paprika-vitamin. (Other scientists used the term to refer to “permeability factor.”) It turned out that variety of plant compounds act as cofactors for vitamin C, not just one “vitamin P.” Szent-György went on to explain how vitamin C interacted with these cofactors and won a Nobel prize. His underlying discovery, however, is often forgotten. Vitamin C is essential to human health and we have to get it from food or supplements. But it is never enough by itself.

What Does Vitamin C Do in the Body?

Plants make vitamin C to counteract the effects of heat and exposure to toxins. They make more vitamin C in hot weather and less vitamin C in cool weather. They make more vitamin C when they are exposed air pollution and less vitamin C when they are not. They make more vitamin C during the day and less at night, and they concentrate vitamin C in their fruit so it can it protect their seeds, which as their “babies.”

Plants use vitamin C to counteract the effects of free radicals of oxygen released when they are making oxygen. Animals use vitamin C to counteract the effects of free radicals of oxygen released when they are consuming oxygen.

Many animals can make their own vitamin C, too. In fact, over 4,000 other species of mammals, all mammals except humans, mice, monkeys, and gorillas, make their own C. A billy goat, for example, can produce up to 200,000 mg of vitamin C a day when needed to repair injured tissues. Humans “almost” can make vitamin C, except that we all lack an enzyme for the last step in the process because we all carry the same mutation in our DNA.

Humans cannot make vitamin C but our red blood cells are uniquely equipped to absorb vitamin C. The transporter proteins that help them absorb glucose for fuel do double duty as vitamin C transporters, so that a red blood cell, which needs all the antioxidants it can get because it travels throughout the body getting exposed to every possible oxidant, absorbs 50% more vitamin C than sugar.

In the human body, the primary job of vitamin C is to serve an antioxidant. Much of the energy the human body produces is made by combining glucose and oxygen. “Burning” any substance releases free radicals of oxygen, and elaborate energy cycles keep almost all the free radicals released during respiration in chemical cycles that protect cells and tissues. About 1 in 10,000,000 free radicals, however, escapes the chemical cycles that normally would control it.

Vitamin C and other antioxidants capture free radicals and keep them from causing damage. Vitamin C also keeps iron and copper in a non-reactive state. This keeps them from generating free radicals that are beneficial for disease-causing bacteria but harmful to healthy human tissues.

Other Uses of Vitamin C

The body uses vitamin C in a number of synthetic processes. Vitamin C participates in the different series of chemical reactions needed to make L-carnitine, the amino acid so important to heart and brain health. It is essential for making collagen, enabling it to form spirals that are much stronger than “strings” of collagen that can be made without vitamin C. It is also essential in the formation of the “feel good” brain chemical dopamine, and it enables chemical changes that make essentially all of the hormones in the body more stable.

The body needs vitamin C to stabilize growth hormone, stress hormones, and the hormones that trigger feelings of enjoyment after sexual activity. Vitamin C stabilizes insulin for transporting glucose, leptin for regulating fat storage, hormones like ghrelin that send a signal to the brain when the stomach is full, and hormones that regulate both urination and bowel movement.

Vitamin C has well-known effects on the immune system. It helps white blood cells make a protein that “glues” the target tissues, such as the linings of the nose and throat when you get a cold. It also helps slow down the release of histamine, the irritant chemical that triggers allergies.

Some commentators claim that when humans consume too much vitamin C, vitamin C has the exact opposite of its desired effects.

In the laboratory, vitamin C does not always act an antioxidant. It sometimes acts as a pro-oxidant, or what you might call an anti-antioxidant. The potential of this effect in the human body is often exaggerated. Taking too much vitamin C won't cause pro-oxidant effects that eat up your tissues. Taking too much vitamin C will just lead you to consume more of the vitamin than your body can absorb.

Are You at Risk for Vitamin C Deficiency?

Since very few of us sign up to be sailors or pirates on wind-powered schooners roaming the seven seas, you would think that vitamin C deficiency would be a relatively rare condition in the modern world. It's actually not.

In 2003 and 2004 the National Health and Nutrition Examination Survey took blood samples from 7,227 American children and adults. They identified three groups that were most likely to be deficient in vitamin C: Children under 6, men between the ages of 20 and 39, and both men and women over the age of 60.

Overall, 6% of American women and 8.2% of American men were found to be deficient in vitamin C. Whites are about two times more likely not to be getting enough vitamin C than African-Americans, Hispanics, and Americans of Asian heritage. Native Americans (Indians) living on tribal reservations, however, tend to have very high rates of all kinds of vitamin deficiencies.

Americans are less likely to be deficient in vitamin C than people in other countries. The Low Income Diet and Nutrition Survey in the UK found that 16% of women and 25% of men had vitamin C levels low enough to cause scurvy-like symptoms. Another 20% of both men and women in the United Kingdom had only borderline levels of vitamin C.

In France, 15% of women and 20% of men over the age of 65 were deficient in C. In Thailand, large numbers of infants fed canned milk developed scurvy. Only Italy are fewer people vitamin C-deficient than in the United States.

What puts a person at risk for vitamin C deficiency?

Eating meals outside the home seems to be a major factor. Children are provided fruit at their school breakfast and lunch programs, but they don't always eat. Many adults eat a steady diet of meat, bread, and potatoes when they eat out.

People who live in rest homes or jails often don't get enough vitamin C, and certain psychiatric disorders, especially obsessive-compulsive disorder, lead to diets that are vitamin C-deficient. People who have to avoid acid foods because of stomach disorders, or who have inflammatory bowel disease, or who receive chemotherapy, also tend to be deficient in C.

Also, about 35% of people of European descent and 50% of people of South Asian descent carry a gene that causes hemoglobin in the bloodstream to break down unusually quickly. This causes the release of free radicals of oxygen that have to neutralized with additional vitamin C.

How Much Vitamin C Is Enough?

National nutritional standards boards define adequate intake of vitamin C in terms of getting enough vitamin C to prevent scurvy. This is more vitamin C than is in some diets but much less vitamin C than is provided by even a single vitamin C tablet.

• Infants usually need “some” vitamin C.
• Children aged 1 to 3 usually need 15 mg per day.
• Children aged 4 to 7 usually need 25 mg per day.
• Tweens aged 8 to 12 usually need 45 mg per day.
• Teens aged 13 to 18 usually need 75 mg per day.
• Adults need at least 75 and possibly up to 125 mg per day.

Treating a disease condition may require a much higher dose of vitamin C.

How Much Vitamin C Is Too Much?

The human body can only store about 1500 mg of vitamin C. This amount of vitamin C may last as long as 3 months, scurvy symptoms only beginning to appear when the body's total supply of vitamin C is about 350 mg.

Taking more than 1500 mg of vitamin C in a single day is a guarantee that vitamin C will be removed by the kidneys and flushed away into the urine, although intravenous vitamin C can accumulate in much larger amounts, up to as much as 100,000 mg in the body as a whole. (Don't try giving yourself intravenous vitamin C unless you are a medical professional.)

When doctors treat scurvy, they usually tell their patients to take 1,000 mg a day for one week and 500 mg a day for the next week. Infants are sometimes helped with a single cup of orange juice. After these small amounts of vitamin C replenish the body's essential stores, just the recommended daily intake is enough to prevent deficiency diseases.

What Difference Could Vitamin C Make in Your Life?

It does not take a lot of vitamin C to avoid vitamin C deficiency. A study in Scotland found that persuading people to eat just one apple or one orange a week, providing as little as 40 mg of vitamin C, was enough to prevent vitamin C deficiency diseases. The amount of vitamin C needed to support recovery from disease, however, is usually much greater. Here are some examples.

Alzheimer's disease. Swedish scientists have observed that adding vitamin C to a test tube culture of brain cells breaks up the protein that accumulates in Alzheimer's disease. Laboratory studies elsewhere have shown that treatment with vitamin C restores normal behavior in rodents that have a condition similar to Alzheimer's disease.

It may be that supplemental vitamin C may be useful in slowing the progression of pre-Alzheimer's or moderate Alzheimer's. Scientists simply do not know yet. Any kind of nutritional therapy for Alzheimer's disease requires caution, because small improvements in mental condition or nerve function may be only enough to increase risk of accidents. An appropriate dosage for Alzheimer's patients is 100 to 1,000 mg a day, but don't give so much as to cause diarrhea.

Asthma. A research study conducted by a team of scientists working at the University of Helsinki in Finland and Tanta University in Egypt have confirmed generations-old advice that vitamin C may help relieve asthma in children. Children aged 7 to 10 had fewer and milder attacks after taking 200 mg of vitamin C per day, but the vitamin's effects were more noticeable for children who are not exposed to dampness and molds.

Cardiovascular disease in people who do not have diabetes. Vitamin C actually does reduce the risk of death from cardiovascular disease, although it's important to know that the benefits of vitamin C don't come from taking more, more, more.

The First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study found that taking at least 359 mg of supplemental vitamin C every day lowered risk of death from cardiovascular disease 25% in women and 42% in men. However, consuming more than 50 mg of vitamin a day from food had no additional effect.

The NHANES II study found that taking more than 400 mg of vitamin C a day in supplements had no additional benefit for younger adults. A regular dose of 400 mg a day seems to saturate the system with vitamin C so that more cannot be absorbed.

The studies that suggest vitamin C may be harmful looked at taking less than the 359 mg a day minimum. One possibility is that small doses of vitamin C improved heart health just enough to allow people to overexert themselves, and significant doses are necessary to enjoy any benefits at all.

Cardiovascular disease in diabetics. One famous study found that taking a combination of vitamin C and vitamin E reduced the risk of developing cardiovascular disease in diabetics. Another famous study found that taking a combination of vitamin C and vitamin E increased the risk of cardiovascular disease in diabetics.

It turns out (although it was never reported by the mainstream press) that diabetics who have two copies of a gene called haptoglobin 1 have lower risk of heart disease when they take C and E and diabetics who have two copies of a gene called haptoglobin 2 have higher risk of heart disease when they take C and E. If you have diabetes, and you don't know your genetic status (and most diabetics don't), avoid taking vitamins C and E except when you are treating a cold or flu.

Colds. We all know about taking vitamin C to prevent and treat colds. There is not really enough vitamin C in orange juice to make a difference in treating a cold. If you feel better when you drink orange juice, it's because your body is burning off the extra sugar you digest from the juice and you will spontaneously breathe more deeply so your lungs can disperse the extra carbon dioxide.

The best way to use vitamin C to fight a cold is to take 2,000 mg in a single dose when you first notice symptoms. A small daily dose of vitamin C (unless you happen to be a marathon runner or participate in some other endurance event) won't prevent colds, but a large dose of vitamin C may help.

Gout. Gout is a form of arthritis that results from the accumulation of uric acid in joints. One study found that increasing bloodstream concentrations of ascorbic acid (vitamin C) displaces uric acid. The minimum dosage is 500 mg a day and it has to be taken for two months.

Sexual dysfunction during antidepressant treatment. The class of antidepressant drugs known as selective serotonin reuptake inhibitors (SSRIs) often cause loss of interest in sex and inability to have sex. The makers of the German vitamin C supplement Cetebe found that their product restored both interest in and ability to have sexual intercourse in younger adults (aged 20 to 35) who had lost interest in sex after taking these medications. Cetebe is a relatively high (3000 mg) dose of vitamin C in a time-released form.

Vitamin C actually has brought about remission from advanced cancer in some cases, but it has to be administered in a special form. This important topic is discussed at the end of this article

The thing that is important to know about using vitamin C to support recovery from disease is that the results are what scientists call “heterogeneous.” Some people will get a lot better, and some people will not. The difference may be some quirk of individual biochemistry or , or whether or not an individual eats plants foods in addition to taking vitamin C, or both.

Getting Vitamin C from Food

How can you get your vitamin C from food? If you eat the recommended 5 servings of fruit and vegetables per day, it is hard not to get enough vitamin C to avoid deficiency. A 3-1/2 oz or 100 gram serving of many foods contains a full day's supply of vitamin C. Here are some examples:

• A 3-1/2 oz (100 gram) serving of Tang or other orange-flavored powdered drink contains 2400 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of fresh acerola (West Indian cherry) contains 1677 mg of vitamin C. There is even more in acerola “leather.”
• A 3-1/2 oz (100 gram) serving of rose hips contains 426 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw green chili peppers contains 242 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of McDonald's apple dippers with caramel sauce contains 210 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of sweet peppers contains 183 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of dried litchi fruit contains 183 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of fresh currants contains 181 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of sauteed red peppers contains 160 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of McDonald's fruit and walnut salad contains 143 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw kale contains 120 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of grapefruit juice contains 120 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of cooked leeks contains 118 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of sliced frozen peaches contains 94 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of of almost any wild greens (pokeweed, fireweed, taro and taro leaves, dandelion greens) contains around 90 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw broccoli (any part of the plant) contains 89 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw Brussels sprouts contains 88 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of most vitamin-fortified breakfast cereals contains 70 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw papayas or fresh pomelo contains 62 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of peeled raw navel oranges or raw strawberries contains 59 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw purple cabbage contains 56 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw lemon pulp (without peel) contains 52 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of boiled kale contains 52 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of orange juice contains 50 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of canned green peppers contains 46 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of raw cauliflower contains 46 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of boiled Brussels sprouts contains 43 mg xx.
• A 3-1/2 oz (100 gram) serving of SPAM (the canned pork product) contains 43 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of watercress contains 43 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of bottled cranberry juice cocktail contains 42 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of frozen strawberries contains 41 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of cooked chopped broccoli or collard greens (previously frozen) contains 40 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of sun dried tomatoes contains 39 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of most organ meats contains 38 to 40 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of “light” luncheon meat contains 38 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of pink or white grapefruit juice contains 38 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of boiled red cabbage contains 38 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of orange juice fortified with calcium and vitamin D contains 32 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of boiled cauliflower (previously frozen) contains 31 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of Swiss chard (silverbeet) contains 30 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of potato pancakes contains 27 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of wild raspberries contains 27 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of canned sweet potatoes contains 26 mg of vitamin C.
• A 3-1/2 oz (100 gram) serving of fried or baked Irish potatoes contains 17 mg of vitamin C.

As you may notice as you scan the list, certain fast foods and junk foods have more vitamin C—many times more vitamin C—than healthy fresh vegetables and fruit. In the case of Tang instant breakfast drink, this is because the manufacturer intended it be a vitamin drink. The makers of cereals and the owners of fast food restaurants are given incentives by the government to make their products “healthier.” The makers of SPAM canned pork product and of lunch meat add vitamin C so their products won't rot before you buy them.

Generally, however, the often-recommended five servings of fruit and vegetables per day ensures you will get more than enough vitamin C to prevent deficiency, although not necessarily enough to help you overcome disease.

Is Organic Better?

Organic produce tends to have more vitamin C than conventionally raised produce. This because the plant has to make more vitamin C to fight damage by insects and molds that pesticide- and fungicide-treated produce does not.

On the other hand, fresher is not necessarily better when it comes to vitamin C. Although B vitamins tend to deteriorate as fruits and vegetables are kept in the refrigerator, vitamin C does not break down as long as produce is kept chilled, at a temperature of about 39° F/4° C. Even when food begins to spoil, it still retains its vitamin C, although it may not retain other nutrients.

Which Is Better, Food or Supplements?

Making the right choice between food and supplements for getting your vitamin C depends on how you intend to use it. Food is best for preventing vitamin C deficiency. Supplements are best for treating vitamin C deficiency and for supporting recovery from disease.

There are major differences among vitamin C supplements.

Vitamin C supplements tend to go bad when they are exposed to humidity. The problem isn't in the vitamin C itself. It's usually in the anti-caking agents vitamin manufacturers add to vitamin C to keep it from caking and clumping as it sits on the shelf.

Anti-caking agents act like little raincoats around tiny particles of vitamin C. They channel moisture away from the particles of the vitamin C they cover, but this moisture has to accumulate somewhere inside the tablet. Only in late 2011 did industry experts discover that some of the additives put into vitamin C supplements actually deplete more C than making vitamin C without any additives at all.

The most reliable form of “additive-free” vitamin C is a product known as acerola USP. It's a dry form of the acerola fruit mentioned above. Not only does this product provide a lot of vitamin C in a small serving, it also provides the “vitamin P” co-factors that help the body use vitamin C.

Ester-C is a product that combines vitamin C with dihydroascrobic acid (mentioned above) and other forms of vitamin C as they are used in the human body. It is not more easily absorbed than other forms of vitamin C, but when it is absorbed, it goes to work faster.

Mineral ascorbates such as sodium ascorbate and calcium ascorbate are less acidic than ascorbic acid, and less likely to cause stomach upset.

Vitamin C and Cancer

In the 1980's, Nobel laureate Linus Pauling became a famous advocate of vitamin C treatment for cancer. Collaborating with a physician named Ewan Cameron, he reported remissions from advanced cancer when patients were given 10,000 mg of vitamin C by intravenous (IV) drip for 10 days, and 10,000 mg of vitamin C day by mouth thereafter.

Then the Mayo Clinic “debunked” Pauling's discovery by reporting no benefit from giving cancer patients 10,000 mg of vitamin C a day by mouth. Even though the Mayo test did not follow Pauling's protocol, vitamin C treatment was relegated to a list of “quack” treatments. The quackbusters of traditional academic medicine, however, may turn out to be wrong.

Hundreds of thousands of people have tried their own versions of vitamin C therapy for cancer with mixed results. Typically the promoter of a vitamin C supplement tells cancer patients they need to take enough vitamin C to cause diarrhea to get enough vitamin C into their bodies to fight cancer. This does not even make good sense (unless your objective is to sell more vitamin C). Diarrhea sends substances out of the body, not in.

However, in 2007, Canadian researchers repeated Pauling's original experiment with three “hopeless” patients who had terminal cancer. These patients went into remission in just days after receiving intravenous vitamin C.

The bottom line seems to be that most of us can't use vitamin C to treat cancer on our own. The only way to get enough of the vitamin directly to the tissues where it is needed is to take intravenous vitamin C. However, IV vitamin C treatment is neither expensive nor dangerous and is offered by many licensed medical practitioners.

Contrary to Internet reports, the US Food and Drug Administration has not banned the practice. It only reprimanded a pharmacy for using tap water to make IV's for vitamin C.

Vitamin C and Chemotherapy

It is never a good idea to take vitamin C when you are taking chemotherapy. When scientists at Memorial Sloan Kettering Hospital in New York tested the effects of a number of different kinds of chemotherapy on cancer cells in laboratory conditions with and without pretreatment with vitamin C, they found that vitamin C reduced the effectiveness of chemotherapy each and every time.

This is not especially hard to understand. Many kinds of chemotherapy work by generating free radicals of oxygen to kill cancer cells. Vitamin C protects healthy cells against free radicals of oxygen. When a cell converts vitamin C into dihydroascorbic acid, it sends a signal to the mitochondria of the cell to keep on making energy. Vitamin C keeps the mitochondria from making still more free radicals of oxygen that might damage the cell's DNA so that it, ironically, might become cancerous. If the cell did not have a supply of dihydroascorbic acid, its mitochondria might shut down and the cell might die.

Vitamin C also protects cancerous cells from free radicals of oxygen. You don't want to protect cancer cells while you are having chemotherapy. If you are going to take chemotherapy at all, wait until after your chemotherapy is completed to restore your body's supply of vitamin C.