During the days of Columbus, sailors who joined the crew of a seagoing ship knew that they had only a 50 percent chance of coming home alive. The danger wasn’t that they might fall off the edge of the Earth or be eaten by sea monsters. Instead, it was that they might contract a dreadful disease, unnamed at the time, that would make their gums bleed, loosen their teeth, cause bruises and bleeding under their skin, and ultimately, kill them. Only men on short voyages, especially around the Mediterranean Sea, seemed able to avoid these symptoms. At that time, no one knew that the disease was scurvy, caused by a deficiency of vitamin C. On long ocean voyages, the cook used up the fresh fruits and vegetables first, then served only cereals and meats, which contained no vitamin C, until the ship returned to port. That sometimes meant that the crew went for months without this essential vitamin.
Even though James Lind, a British physician, showed in 1747 that oranges and lemons could prevent scurvy, it was another 50 years before the British navy mandated a daily ration of lime juice on all vessels (thus giving British sailors the traditional nickname, limeys). And it took another 200 years before the component of citrus that protected against scurvy, vitamin C, was isolated. Its scientific name, ascorbic acid, reflects its anti-scurvy past.
Our C Rations
These days, we get so much vitamin C from foods that we never have to worry about scurvy or lime juice rations. A lot of us even keep bottles of vitamin C on hand so we can down a couple of hundred extra milligrams if we feel a cold coming on. In fact, vitamin C is the most popular vitamin supplement in the United States. And while it may be best known for its cold-fighting powers, that’s just one of its vital roles in the body.
Body Building
Vitamin C helps to form the fibrous structural protein known as collagen, the single most important protein of connective tissue and literally, the stuff that holds us together.
SUPPLEMENTSNAPSHOT
| Vitamin C Also known as: Ascorbic acid. May help: Bacterial and viral infections, including colds and flu, HIV, and urinary tract infections; cancer; gingivitis; genital herpes; asthma; emphysema; angina; cataracts; sunburn; bedsores; diabetes-related organ damage; depression; impotence; intermittent claudication; phlebitis; infertility; high cholesterol; heavy menstrual bleeding; muscle soreness; osteoarthritis; menopausal discomforts; chronic inflammatory diseases such as lupus and rheumatoid arthritis; recovery from surgery or injury; and exposure to toxins. Daily Value: 60 milligrams; for smokers, 100 milligrams. Special instructions: Take larger doses in several spaced doses of less than 1,000 milligrams each throughout the day. Take with adequate amounts of water. Who’s at risk for deficiency: Smokers and people exposed to cigarette smoke; people with viral or bacterial infections, diabetes, high cholesterol, cardiovascular disease, cancer, or chronic inflammation; and people who take aspirin or barbiturates regularly. Good food sources: Broccoli, brussels sprouts, cabbage, chile peppers, citrus fruits, collard and turnip greens, guavas, kale, parsley, red and green bell peppers, and strawberries. Cautions and possible side effects: Safe at a wide range of doses, although more than 1,000 milligrams a day can cause diarrhea; if this occurs, cut back until the diarrhea stops. If you’re taking high doses, cut back to 100 milligrams at least three days before a physical exam or tests, as high amounts can interfere with some tests, including those for blood in the stool and sugar in urine. Large doses may interfere with anticoagulants (blood thinners). Supplements made from a corn base may cause a reaction in people allergic to corn. |
"Vitamin C lets these fibers cross-link, or weave together, to make them strong," explains Robert Jacob, Ph.D., a research chemist in micronutrients at the U.S. Department of Agriculture Western Human Nutrition Research Center in San Francisco.
When these fibers don’t cross-link, we get the symptoms typical of scurvy. We start to fall apart. Our teeth loosen because our gums can’t hold them in anymore; our gums bleed, and we develop little pinpoints of blood under our skin as blood vessels break down and release blood. If we get hurt, we don’t heal, because the body relies on collagen to fill the gaps in wounds. If we break a bone, it doesn’t heal either, because bones regenerate by depositing minerals such as calcium on a matrix of collagen.
Some doctors believe that a low intake of vitamin C does more than aggravate the symptoms of scurvy, says Balz Frei, Ph.D., professor of biochemistry and biophysics and director of the Linus Pauling Institute at Oregon State University in Corvallis. A shortage may also worsen symptoms of osteoporosis, cancer, and heart disease.
Fat for Fuel
One of the first symptoms of vitamin C deficiency is fatigue, and one reason for that may be an often-overlooked function of this vitamin, says Dr. Frei. "Vitamin C is required for the synthesis of a compound called carnitine, which transports fatty acids into the mitochondria, the tiny powerhouses that generate energy inside cells," he explains. "If you don’t have enough vitamin C, you can’t synthesize enough carnitine, so you can’t convert all the fatty acids into usable energy."
While it’s true that carbohydrates are the main source of energy for most of our body parts, fatty acids are the major sources for the production of energy in the heart and skeletal muscles. These areas are particularly vulnerable to a carnitine shortage, Dr. Frei says.
Vitamin C also helps your body convert the amino acid tyrosine into two important hormones, epinephrine and norepinephrine. Both are released by the body in response to stress.
"These hormones are responsible for mobilizing energy and activating a lot of metabolic pathways so that you can respond to stressful situations in a physical way," Dr. Frei explains. "They produce the fight-or-flight response."
In fact, our adrenal glands, which produce these two hormones, have a higher concentration of vitamin C than any other organ in the body. "It’s well-established that if you’re under physical stress, such as during an infection or after surgery, you need more vitamin C," Dr. Jacob says. "There’s less evidence to indicate that psychological stress also raises vitamin C needs, but since psychological stress also makes the adrenal glands crank up production, it makes sense that you would need more vitamin C."
| The Rationale behind Megadosing Some doctors recommend so-called megadoses of vitamin C, amounts far higher than the Daily Value, to literally flood the body with the vitamin during certain illnesses. The thinking is this: Many illnesses involve damage from free radicals, unstable molecules that affect healthy cells. Once it gets started, the damage can cause a chain reaction that quickly depletes areas of inflamed tissue of vitamin C and allows the damage to spread even more. “I am trying to literally pickle the tissues involved in the disease in order to neutralize all the free radicals,” says Robert Cathcart, M.D., a physician in Los Altos, California, who is a long-time practitioner of megadosing. “I want to push the vitamin into cells and flood the tissue to stop the chain reaction of free radical damage. This is not a nutritional effect. Rather, it is a pharmacological effect.” Dr. Cathcart recommends and has successfully used large doses of vita min C in the form of ascorbic acid. In this form, the vitamin isn’t buffered—that is, no chemicals have been added to help the body absorb it. The ascorbic acid, he says, can help with many kinds of health conditions, from the common cold to life-threatening viral hepatitis. Normally, he recommends that his patients take the vitamin to bowel tolerance (meaning until it begins to produce loose stools), and then back off a bit until the loose stools stop. His reasoning: When people are sick, they tend to tolerate a lot more ascorbic acid than they do when they are healthy. The one exception is people with bowel problems, who may not be able to take much ascorbic acid orally. In these cases, Dr. Cathcart administers a form of the vitamin intravenously. For a bad cold or the flu, for instance, Dr. Cathcart might recommend that someone take 2 to 12 grams of ascorbic acid every 15 minutes until they reach bowel tolerance. The time frame varies from person to person, but tolerance could occur within four to eight hours, Dr. Cathcart says. For a condition like severe mononucleosis, he says, one woman was able to tolerate 200 grams of ascorbic acid before she reached bowel tolerance. “When you reach that point,” Dr. Cathcart says, “generally, your symptoms quickly vanish.” How long you need to take high amounts to keep your symptoms at bay depends on many variables and could range from a few days to months. Some people take several grams a day indefinitely. While there is some research to indicate that taking additional vitamin C can help shorten the duration of a cold, there is little evidence to support the use of large amounts for illnesses such as mononucleosis, hepatitis, cancer, or AIDS, says Balz Frei, Ph.D., professor of biochemistry and biophysics and director of the Linus Pauling Institute at Oregon State University in Corvallis. “I’m not saying that it doesn’t work or that the theory behind this isn’t sound. I’m saying that there is currently not enough scientific evidence to conclude that megadoses of vitamin C provide health benefits beyond those of more moderate doses of the vitamin,” he says. As for everyday, or anti-aging, use of vitamin C, Dr. Cathcart believes that the amount an individual needs is based on their own “free radical load.” “If you have a chronic illness or inflammation, if you’ve abused your body with alcohol or smoking, or if you look old for your age, you probably can use more than someone who’s healthier,” he says. For a vitamin regimen tailored to your needs, see your doctor. |
Stopping the Thieves
In the annals of research, vitamin C has won considerable renown as an antioxidant. That means that it helps keep a lid on chemical reactions that involve oxygen, explains Dr. Frei—reactions that go on all the time, all over our bodies. We have oxygen in our lungs, but blood carries it to every cell, where it is used as part of the process of energy metabolism. These chemical reactions have the potential to create molecular particles called free radicals. A free radical lacks an electron, which makes it unstable, so it tries to "steal" an electron from some other molecule. Then that molecule is minus an electron and becomes a free radical, causing a kind of free radical domino effect.
Vitamin C breaks up this cycle of larceny. "It can give up one of its electrons without becoming a dangerous free radical, so every time a molecule of vitamin C does that, it helps to stop a whole string of electron pilfering," Dr. Frei explains. That’s important because free radical damage is thought to be involved in many diseases and conditions, including inflammation, viral infections, cancer, heart disease, and even aging.
Vitamin C can also regenerate vitamin E, another important free radical scavenger, by giving it an electron.
As an antioxidant, vitamin C helps many parts of the body function better. When immune cells are called into action, for instance, they use a lot of oxygen and produce free radicals and oxidants that can damage cells and surrounding tissue. Vitamin C helps protect these cells.
In your lungs, this versatile vitamin helps you breathe more easily by fighting off the onslaught of oxidants you inhale, says Dr. Frei, especially if you are a smoker. In your liver, it helps to protect the cells as they break down toxins. And in your stomach, vitamin C is secreted in gastric juices and helps to neutralize potential cancer-causing substances called nitrosamines, which are found in some lunch meats and smoked foods.
How Much Is Enough?
Only about one out of every four Americans gets less than the Daily Value for vitamin C, which is 60 milligrams. They are people who simply don’t eat fruits and vegetables, Dr. Frei says.
The bigger question today is how much vitamin C is optimum for good health. Dr. Frei believes that everyone should get a minimum of 200 milligrams, and in fact, studies show that in healthy people, 200 milligrams daily produces tissue saturation. It’s about as much as most parts of your body can hold.
There are some decent arguments that can be made for some people’s need for higher amounts, however. Smokers and people exposed to cigarette smoke; people with viral or bacterial infections, diabetes, high cholesterol, cardiovascular disease, cancer, or chronic inflammation; and people who take certain drugs such as aspirin or barbiturates on a regular basis may need more vitamin C, Dr. Frei says.
