Vitamin C
Vitamin C is a water-soluble vitamin that is necessary for normal growth and development.
Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.
Function Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to
Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals.
The body is not able to make vitamin C on its own, and it does not store vitamin C. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.
For many years, vitamin C has been a popular remedy for the common cold.
Food Sources:
All fruits and vegetables contain some amount of vitamin C.
Fruits with the highest sources of vitamin C include:
Some cereals and other foods and beverages are fortified with vitamin C. Fortified means a vitamin or mineral has been added to the food. Check the product labels to see how much vitamin C is in the product.
Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving and steaming vitamin C-rich foods may reduce cooking losses. The best food sources of vitamin C are uncooked or raw fruits and vegetables.
Side EffectsSerious side effects from too much vitamin C are very rare, because the body cannot store the vitamin. However, amounts greater than 2,000 mg/day are not recommended because such high doses can lead to stomach upset and diarrhea.
Too little vitamin C can lead to signs and symptoms of deficiency, including:
A severe form of vitamin C deficiency is known as scurvy, which mainly affects older, malnourished adults.
RecommendationsThe Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.
How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important.
The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods.
Dietary Reference Intakes for vitamin C:
Infants
Children
Smokers or those who are around secondhand smoke at any age should increase their daily amount of vitamin C an additional 35 mg per day.
Women who are pregnant or breastfeeding and those who smoke need higher amounts of vitamin C. Ask your doctor what amount is best for you.
Alternative NamesAscorbic acid; Dehydroascorbic acid.
Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.
Function Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to
- Form an important protein used to make skin, tendons, ligaments, and blood vessels
- Heal wounds and form scar tissue
- Repair and maintain cartilage, bones, and teeth
Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals.
- Free radicals are made when your body breaks down food or when you are exposed to tobacco smoke or radiation.
- The buildup of free radicals over time is largely responsible for the aging process.
- Free radicals may play a role in cancer, heart disease, and conditions like arthritis.
The body is not able to make vitamin C on its own, and it does not store vitamin C. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.
For many years, vitamin C has been a popular remedy for the common cold.
- Research shows that for most people, vitamin C supplements or vitamin C-rich foods do not reduce the risk of getting the common cold.
- However, people who take vitamin C supplements regularly might have slightly shorter colds or somewhat milder symptoms.
- Taking a vitamin C supplement after a cold starts does not appear to be helpful.
Food Sources:
All fruits and vegetables contain some amount of vitamin C.
Fruits with the highest sources of vitamin C include:
- Cantaloupe
- Citrus fruits and juices, such as orange and grapefruit
- Kiwi fruit
- Mango
- Papaya
- Pineapple
- Strawberries, raspberries, blueberries, cranberries
- Watermelon
- Broccoli, Brussels sprouts, cauliflower
- Green and red peppers
- Spinach, cabbage, turnip greens, and other leafy greens
- Sweet and white potatoes
- Tomatoes and tomato juice
- Winter squash
Some cereals and other foods and beverages are fortified with vitamin C. Fortified means a vitamin or mineral has been added to the food. Check the product labels to see how much vitamin C is in the product.
Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving and steaming vitamin C-rich foods may reduce cooking losses. The best food sources of vitamin C are uncooked or raw fruits and vegetables.
Side EffectsSerious side effects from too much vitamin C are very rare, because the body cannot store the vitamin. However, amounts greater than 2,000 mg/day are not recommended because such high doses can lead to stomach upset and diarrhea.
Too little vitamin C can lead to signs and symptoms of deficiency, including:
- Anemia
- Bleeding gums
- Decreased ability to fight infection
- Decreased wound-healing rate
- Dry and splitting hair
- Easy bruising
- Gingivitis (inflammation of the gums)
- Nosebleeds
- Possible weight gain because of slowed metabolism
- Rough, dry, scaly skin
- Swollen and painful joints
- Weakened tooth enamel
A severe form of vitamin C deficiency is known as scurvy, which mainly affects older, malnourished adults.
RecommendationsThe Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.
How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important.
The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods.
Dietary Reference Intakes for vitamin C:
Infants
- 0 - 6 months: 40* milligrams/day (mg/day)
- 7 - 12 months: 50* mg/day
Children
- 1 - 3 years: 15 mg/day
- 4 - 8 years: 25 mg/day
- 9 - 13 years: 45 mg/day
- Girls 14 - 18 years: 65 mg/day
- Boys 14 - 18 years: 75 mg/day
- Men age 19 and older: 90 mg/day
- Women age 19 year and older: 75 mg/day
Smokers or those who are around secondhand smoke at any age should increase their daily amount of vitamin C an additional 35 mg per day.
Women who are pregnant or breastfeeding and those who smoke need higher amounts of vitamin C. Ask your doctor what amount is best for you.
Alternative NamesAscorbic acid; Dehydroascorbic acid.
Glutathione
What Is Glutathione?
"Glutathione is a very interesting, very small molecule that's [produced by the body and] found in every cell," says Gustavo Bounous, MD, director of research and development at Immunotec and a retired professor of surgery at McGill University in Montreal, Canada. "It's the [body's] most important antioxidant because it's within the cell."
Antioxidants - the most well known of which are vitamins C and E - are important for good health because they neutralize free radicals, which can build up in cells and cause damage. Because glutathione exists within the cells, it is in a prime position to neutralize free radicals. It also has potentially widespread health benefits because it can be found in all types of cells, including the cells of the immune system, whose job is to fight disease.
Glutathione occurs naturally in many foods, and people who eat well probably have enough in their diets, says Dean Jones, PhD, professor of biochemistry and director of nutritional health sciences at Emory University in Atlanta. Those with diets high in fresh fruits and vegetables and freshly prepared meats are most likely just fine. On the other hand, those with poor diets may get too little.
What Does Glutathione Do?
The strong antioxidant effect of glutathione helps keep cells running smoothly. Bounous and another glutathione expert, Jeremy Appleton, ND, say it also helps the liver remove chemicals that are foreign to the body, such as drugs and pollutants.
Appleton is chairman of the department of nutrition at the National College of Naturopathic Medicine in Portland, Ore., and senior science editor for Healthnotes, a database on complementary and alternative medicineavailable at newspaper stands and health food stores.
Evidence for the important role that glutathione plays in health comes from studies in people who are severely ill.
"If you look in a hospital situation at people who have cancer, AIDS, or other very serious disease, almost invariably they are depleted in glutathione," says Appleton. "The reasons for this are not completely understood, but we do know that glutathione is extremely important for maintaining intracellular health."
How Should Glutathione Be Taken?
Glutathione is probably not well absorbed into the body when taken by mouth. One way to get around that is to take it by vein. A more practical solution is to take the precursors -- that is, the molecules the body needs to make glutathione -- rather than glutathione itself. While there is no solid proof this works, the consensus among experts is that that doing so will increase the amount of glutathione in the cells.
Bounous has developed a glutathione-enhancing product called Immunocal, which is made up of glutathione precursors, mainly the amino acid cysteine.
Who Does Glutathione Help?
Animal and laboratory studies have demonstrated that glutathione has the potential to fight almost any disease, particularly those associated with aging, since free radical damage is the cause of many of the diseases of old age.
"Theoretically, there are many very strong arguments in favor of a therapeutic use of glutathione," says Appleton. "But when people have actually tried to use glutathione as an oral supplement, nasal spray, or intravenously, the results have been more of a preliminary nature. The amount of research on glutathione as a supplement ... is very limited."
Nevertheless, people have tried glutathione for the treatment of a whole host of conditions, including cancer, high blood pressure, Parkinson's disease, Alzheimer's disease, cataracts, and male infertility.
The best studies have been conducted in cancer. One study involved women with ovarian cancer who were being treated with chemotherapy. Some of the women were also treated with intravenous glutathione. Those given the glutathione not only had fewer side effects from the chemotherapy but also had better overall survival rates.
Myriam Abalain of Montreal, Canada, is one of the many people who have taken Bounous's Immunocal to combat cancer. In 1996, at age 33, a routinePAP smear revealed she had precancerous cells on her cervix, which is one step away from having cervical cancer. The three specialists she visited all told her that a hysterectomy was her only option, but she hesitated to have such major, life-altering surgery.
Instead, she waited. For more than two years, her condition remained stable. Then a friend suggested she try Immunocal. After eight months of taking the supplement, her physician could no longer detect any precancerous cells. Does this mean Immunocal cured her? It's hard to say based on just one case like hers. It is possible her body went into remission naturally.
Even Bounous acknowledges there's no real proof his product cured her cancer, but he's working on conducting good clinical research, comparing individuals with cancer taking glutathione to those who are not.
What Are the Risks?
Overall, taking glutathione or its precursors in reasonable amounts appears to be quite safe, although it should be avoided in people with milk protein allergies and in those who have received an organ transplant. There is also some concern, however, about the safety of taking glutathione for the one condition for which there is the greatest evidence of its usefulness: cancer.
"People don't get concerned about these health-promoting [supplements] until they're in their 50s and 60s," says Emory's Dean Jones. At that point, they may already have the initial precancerous [cells]. Therefore, the supplements, just like they promote health in normal tissues, might promote health in the precancerous tissue."
Appleton recognizes this possibility but says "there's no evidence that supplementing with glutathione, even intravenously, is in any way going to make any cancer worse. In fact, the evidence we have suggests the opposite. It suggests that glutathione and other antioxidants, far from interfering with the activity of chemotherapy, appear to reduce side effects without decreasing efficacy and may, in fact, improve the efficacy of the chemotherapy in fighting cancer."
Bounous says his research has demonstrated that taking Immunocal actually lowers glutathione in cancer cells while increasing it in normal cells. As a result, the cancer cells are more vulnerable to chemotherapy, and the normal cells are protected.
The upshot? The experts disagree on who should take glutathione or its precursors. Bounous says everyone should take it in order to optimize overall health. Appleton would reserve it for people with cancer. Jones says it might only prove beneficial for those who eat poorly and are thus unlikely to be getting much glutathione or its precursors in their diet.
They all acknowledge that people with severe diseases known to be associated with low glutathione levels, such as AIDS, may well benefit from the supplement, although there is no proof to this effect.
For her part, Myriam Abalain is still taking Immunocal and feeling fine. "I'm doing pretty good now," she says. "I'm in better shape than ever!"
"Glutathione is a very interesting, very small molecule that's [produced by the body and] found in every cell," says Gustavo Bounous, MD, director of research and development at Immunotec and a retired professor of surgery at McGill University in Montreal, Canada. "It's the [body's] most important antioxidant because it's within the cell."
Antioxidants - the most well known of which are vitamins C and E - are important for good health because they neutralize free radicals, which can build up in cells and cause damage. Because glutathione exists within the cells, it is in a prime position to neutralize free radicals. It also has potentially widespread health benefits because it can be found in all types of cells, including the cells of the immune system, whose job is to fight disease.
Glutathione occurs naturally in many foods, and people who eat well probably have enough in their diets, says Dean Jones, PhD, professor of biochemistry and director of nutritional health sciences at Emory University in Atlanta. Those with diets high in fresh fruits and vegetables and freshly prepared meats are most likely just fine. On the other hand, those with poor diets may get too little.
What Does Glutathione Do?
The strong antioxidant effect of glutathione helps keep cells running smoothly. Bounous and another glutathione expert, Jeremy Appleton, ND, say it also helps the liver remove chemicals that are foreign to the body, such as drugs and pollutants.
Appleton is chairman of the department of nutrition at the National College of Naturopathic Medicine in Portland, Ore., and senior science editor for Healthnotes, a database on complementary and alternative medicineavailable at newspaper stands and health food stores.
Evidence for the important role that glutathione plays in health comes from studies in people who are severely ill.
"If you look in a hospital situation at people who have cancer, AIDS, or other very serious disease, almost invariably they are depleted in glutathione," says Appleton. "The reasons for this are not completely understood, but we do know that glutathione is extremely important for maintaining intracellular health."
How Should Glutathione Be Taken?
Glutathione is probably not well absorbed into the body when taken by mouth. One way to get around that is to take it by vein. A more practical solution is to take the precursors -- that is, the molecules the body needs to make glutathione -- rather than glutathione itself. While there is no solid proof this works, the consensus among experts is that that doing so will increase the amount of glutathione in the cells.
Bounous has developed a glutathione-enhancing product called Immunocal, which is made up of glutathione precursors, mainly the amino acid cysteine.
Who Does Glutathione Help?
Animal and laboratory studies have demonstrated that glutathione has the potential to fight almost any disease, particularly those associated with aging, since free radical damage is the cause of many of the diseases of old age.
"Theoretically, there are many very strong arguments in favor of a therapeutic use of glutathione," says Appleton. "But when people have actually tried to use glutathione as an oral supplement, nasal spray, or intravenously, the results have been more of a preliminary nature. The amount of research on glutathione as a supplement ... is very limited."
Nevertheless, people have tried glutathione for the treatment of a whole host of conditions, including cancer, high blood pressure, Parkinson's disease, Alzheimer's disease, cataracts, and male infertility.
The best studies have been conducted in cancer. One study involved women with ovarian cancer who were being treated with chemotherapy. Some of the women were also treated with intravenous glutathione. Those given the glutathione not only had fewer side effects from the chemotherapy but also had better overall survival rates.
Myriam Abalain of Montreal, Canada, is one of the many people who have taken Bounous's Immunocal to combat cancer. In 1996, at age 33, a routinePAP smear revealed she had precancerous cells on her cervix, which is one step away from having cervical cancer. The three specialists she visited all told her that a hysterectomy was her only option, but she hesitated to have such major, life-altering surgery.
Instead, she waited. For more than two years, her condition remained stable. Then a friend suggested she try Immunocal. After eight months of taking the supplement, her physician could no longer detect any precancerous cells. Does this mean Immunocal cured her? It's hard to say based on just one case like hers. It is possible her body went into remission naturally.
Even Bounous acknowledges there's no real proof his product cured her cancer, but he's working on conducting good clinical research, comparing individuals with cancer taking glutathione to those who are not.
What Are the Risks?
Overall, taking glutathione or its precursors in reasonable amounts appears to be quite safe, although it should be avoided in people with milk protein allergies and in those who have received an organ transplant. There is also some concern, however, about the safety of taking glutathione for the one condition for which there is the greatest evidence of its usefulness: cancer.
"People don't get concerned about these health-promoting [supplements] until they're in their 50s and 60s," says Emory's Dean Jones. At that point, they may already have the initial precancerous [cells]. Therefore, the supplements, just like they promote health in normal tissues, might promote health in the precancerous tissue."
Appleton recognizes this possibility but says "there's no evidence that supplementing with glutathione, even intravenously, is in any way going to make any cancer worse. In fact, the evidence we have suggests the opposite. It suggests that glutathione and other antioxidants, far from interfering with the activity of chemotherapy, appear to reduce side effects without decreasing efficacy and may, in fact, improve the efficacy of the chemotherapy in fighting cancer."
Bounous says his research has demonstrated that taking Immunocal actually lowers glutathione in cancer cells while increasing it in normal cells. As a result, the cancer cells are more vulnerable to chemotherapy, and the normal cells are protected.
The upshot? The experts disagree on who should take glutathione or its precursors. Bounous says everyone should take it in order to optimize overall health. Appleton would reserve it for people with cancer. Jones says it might only prove beneficial for those who eat poorly and are thus unlikely to be getting much glutathione or its precursors in their diet.
They all acknowledge that people with severe diseases known to be associated with low glutathione levels, such as AIDS, may well benefit from the supplement, although there is no proof to this effect.
For her part, Myriam Abalain is still taking Immunocal and feeling fine. "I'm doing pretty good now," she says. "I'm in better shape than ever!"