Vitamin C

Singer

For the Record…

Selected discography

Sources

Vitamin C is a pop singer whose colorful image, talent for reinvention and several chart-toppers has earned her a place among the abundance of teen pop divas in the year 2001. Her catchy vocals and dynamic presence have linked her musically with the likes of young starlets Britney Spears and Christina Aguilera. However, her career, which included a stint as the vocalist for alternative pop-punk band Eve’s Plum and several acting roles in major motion pictures has been likened to that of Madonna’s. Both women have been acknowledged for their firm multi-media presence. Ironically, the vocalist whose hit single “Graduation (Friends Forever),” made her a favorite among teen music fans, was hardly a teenager when her breakthrough occurred. The singer holds an approximate ten-year age jump over her musical contemporaries as well as the majority of her audience.

Vitamin C was born Colleen Fitzpatrick on July 20, 1969, in Old Bridge, New Jersey, the youngest of three children. While the vocalist denies coming from a creative family, it may have been obvious from an early age she was destined for a career in the arts. As Vitamin C explained to Interview’s Vivian Golden, “From the time I was a little girl I was just one of those kids that would grab the typewriter and try to write a play or a novel.” As a preteen, Fitzpatrick, diagnosed with a foot problem, began dancing as a form of physical therapy. Much to the dismay of her parents, by the age of 13 she was already securing professional jobs in the field. The talented youngster proceeded to sign with an agent and subsequently performed in several music videos and commercials.

During high school, Fitzpatrick had a fortunate break when she landed a part in eccentric director John Water’s 1988 film Hairspray. Despite having a substantial role playing the part of Amber Von Tussle, archenemy to (now talk-show host) star Ricki Lake’s character Tracey Turnblad, she continued with her education at New York University (NYU). Initially it may have seemed the ambitious teenager had her feet firmly planted in the possibility of a dance or acting career. However, Fitzpatrick expressed that she had always been interested in music. “I used to take a tennis racquet and pretend that I was playing guitar,” she explained to Interview magazine. “I saw music as a vehicle to get out all the stuff I couldn’t say.” While she was inspired early on by mega-groups The Beach Boys and The Beatles and later by grunge rockers such as The Breeders, it wasn’t until the early nineties that she chose to utilize music as her main form of self-expression. Fitzpatrick proceeded to implement herself in the New York City club scene and began performing with the New Wave band, Pure Liquid.

In 1991, several months prior to graduating from NYU, Fitzpatrick answered an ad in New York paper The Village Voice which sought a vocalist. She was surprised to find the advertisement had actually been

For the Record…

Born Colleen Fitzpatrick on July 20, 1969, in Old Bridge, NJ; daughter of Gerard (a communications executive) and Vita (a legal secretary). Education: Bachelor of arts degree, New York University, 1991.

Began dancing as a child and by age 13 was securing professional jobs in the field; prior to career in music, landed several small acting rolls; played Amber Von Tussle in Hairspray, 1988; appeared in Naked Gun 2 1/2, 1991; appeared in The Mambo Kings, 1992; formed pop-punk band, Eve’s Plum, 1991; group signed to Sony Music, 1992; released Envy, 1993; released Cherry Alive, 1995; left Eve’s Plum, 1996; signed development deal with Elektra Records and began working under the name Vitamin C, 1998; released Vitamin C, 1999; had top ten single “Graduation (Friends Forever),” 1999; released More, 2000; played Lucy in Dracula 2000, 2000.

Addresses: Record company —Elektra Entertainment, 75 Rockefeller Plaza, 15th floor, 10019. Website-Vitamin C at Elektra Records: http://www.vitamincisgood4u.com.

placed by Michael Kotch, one of her college classmates. Impressed by her ability, Kotch along with his twin brother, Ben (drums), asked Fitzpatrick to join their group. With the addition of bassist Theo Mack, the four aspiring musicians conjointly evolved into pop punk outfit, Eve’s Plum. The group was named for the actress who played often-troubled middle child Jan Brady on the family sitcom The Brady Bunch. After establishing a grassroots following, Eve’s Plum soon found themselves in the midst of a record label bidding war, culminating with the group signed to Sony Music in 1992. The band subsequently put forth their debut Envy in 1993 and a second album, Cherry Alive, two years later. Both were received to moderate success. Unfortunately, the band failed to make the impact in which the record label expected. In 1996, the group was dropped by Sony Music. Fitzpatrick, frustrated with her bandmates’ unwillingness to experiment with a new sound amicably parted ways with the group, thereafter traveling to Los Angeles in order to contemplate her next move.

In the midst of a bad depression, Fitzpatrick wrote the song “Smile.” It invariably lightened her spirits and pointed her interests in a more positive direction. She returned to New York with the intentions to reinvent herself. The result: the once-edgy vocalist emerged as pop star Vitamin C, a move criticized by many as selling out. However, Fitzpatrick proudly defends her position. “People need to see the sense of humor in it,” she explained to Gear magazine, “With Vitamin C, I wanted to do ’no rules’ pop. Everything is all about branding now, everything has to come back to this one image and I’ve never seen myself as that. When I was growing up artists challenged you, they were more creative.” Fitzpatrick landed a development deal with Elektra Records in 1998 and for the next year worked with a series of collaborators and producers to develop her 1999 self-titled debut. Vitamin C’s syrupy high-school anthem “Graduation (Friends Forever)” which Entertainment Weekly described as “destined to become as much a June perennial as Alice Cooper’s ’School’s Out,’” helped turn the album platinum and in turn parlayed Vitamin C into a pop icon.

Despite being in her late twenties at the time, Vitamin C was grouped into a set of teen heroes including Britney Spears, Christina Aguilera, and Mandy Moore. This could be attributed to the saccharine hooks of her first effort, but most notably to her popular image. The attractive blonde singer maintains a dramatic visual appeal, frequently sporting stylish clothes and a bright, multi-colored head of hair. Her trendsetting look has proven to be widely admired by fans and the fashion conscious alike. According to Cosmopolitan magazine, “In an era of cookie-cutter music video presences, her catchy tunes and ever-changing Day-Glo locks have made her refreshingly one of a kind.” In August of 2000, the Mattel toy company issued a Vitamin C doll, complete with interchangeable hair extensions, a microphone and platform shoes. Additionally, Tommy Hilfiger, a popular clothing designer, named an exclusive shade of lipstick “Vitamin C” in the colorful singer’s honor.

At the end of 2000, Vitamin C released her sophomore effort More. Due to the success of her first album, on More the prolific singer had the assistance of many notable collaborators, including Billy Steinberg (a co-writer on Madonna’s “Like a Virgin”), Billy Mann (who had worked with Jennifer Lopez) and Andy Marvel (who had worked with Celine Dion and the Cover Girls. ) The record was a catchy, slightly more mature offering. While it comfortably maintained Vitamin C’s pop appeal, it definitely held a more adult edge than its predecessor. This is evidenced particularly by two notable tracks on the album: “Sex Has Come Between Us” and the indiscreetly flirtatious “The Itch.” A&R guru Josh Deutsch, who worked with Vitamin C on her debut, explained in a 2000 press release, “I think this record is more charged all the way around. Lyrically it’s more challenging and I think it’s musically more dangerous—a little more risk taking going on. Vitamin C has an incredible ability to go in different directions and still be true to herself.”

Refusing to stick with one medium, shortly after releasing her second album, the pop songstress made several appearances on the silver screen. She played the part of the infamous Lucy, a good girl gone bad, in famed horror director Wes Craven’s Dracula 2000 and also had a role in Get Over It, a movie starring popular teen actress Kirsten Dunst. In 2001, Vitamin C continued to be a successful, multi-dimensional artist, one whose talent for reinvention enables her to successfully transform from icon to actress to musician without missing a beat.

Selected discography

Singles

“Smile” (CD5/cassette single), Elektra/Asylum, 1999.

“Smile” (vinyl single), Elektra/Asylum, 1999.

“Me Myself and I” (CD5/cassette single), Elektra/Asylum, 1999.

“Itch” (CD5/cassette single), 2000.

“Graduation/Itch” (CD5/single), Warner/Elektra/Atlantic, 2001.

Albums

Vitamin C, Elektra/Asylum, 1999.

More, Elektra/Asylum, 2000.

Sources

Periodicals

Cosmopolitan, February 2001.

Entertainment Weekly, June 30, 2000; January 26, 2001.

Gear, April 2001.

Interview, December 2000.

People, January 29, 2001.

Rolling Stone, February 1, 2001.

Teen People, December 2000/January 2001.

US Weekly, March 26, 2001.

Online

Hip Online, http://www.hiponline.com (April 14, 2001).

Imusic, http://www.imusic.artistdirect.com (April 17, 2001).

Vitamin C, http://www.vitamincfan.com (April 14, 2001).

Throttlebox, http://www.throttlebox.com (April 16, 2001).

Ultimate Band List, http://www.ubl.com (April 14, 2001).

Additional information was provided by Elektra Entertainment publicity materials, 2000.

—Nicole Elyse

Vitamin C

Description

Vitamin C, or ascorbic acid, is naturally produced in fruits and vegetables. The vitamin, which can be taken in dietary or supplementary form, is absorbed by the intestines. That which the body cannot absorb is excreted in the urine. The body stores a small amount, but daily intake, preferably in dietary form, is recommended for optimum health.

Certain health conditions may cause vitamin C depletion, including diabetes and high blood pressure. People who smoke and women who take estrogen may also have lower vitamin C levels. In addition, men are more likely to be vitamin C depleted, as are the elderly. High stress levels have also been linked to vitamin C deficiency.

In addition, certain medical and surgical procedures may lower the levels of vitamin C in the body. It has been found that hemodialysis causes patients with kidney disease to lose as much as 66 mg per session. Similarly, patients who have had kidney transplants are at increased risk of vitamin C deficiency.

Severe vitamin C deficiency leads to scurvy, a disease common on ships prior to the eighteenth century, due to the lack of fresh fruits and other dietary vitamin C sources. Symptoms of scurvy include weakness, bleeding, tooth loss, bleeding gums, bruising, and joint pain . Less serious vitamin C depletion can have more subtle effects such as weight loss, fatigue , weakened immune system (as demonstrated by repeated infections and colds), bruises that occur with minor trauma and are slow to heal, and slow healing of other wounds .

Low vitamin C levels have also been associated with high blood pressure, increased heart attack risk, increased risk for developing cataracts , and a higher risk for certain types of cancer (i.e., prostate, stomach, colon, oral, and lung).

General use

Vitamin C is a critical component of both disease prevention and of basic body building processes. The therapeutic effects of vitamin C include:

• Allergy and asthma relief. Vitamin C is present in the lung's airway surfaces, and insufficient vitamin C levels have been associated with bronchial constriction and reduced lung function. Some studies have associated vitamin C supplementation with asthmatic symptom relief, but results have been inconclusive and further studies are needed.
• Cancer prevention. Vitamin C is a known antioxidant and has been associated with reduced risk of stomach, lung, colon, oral, and prostate cancer.
• Cataract prevention. Long-term studies on vitamin C supplementation and cataract development have shown that supplementation significantly reduces the risk of cataracts, particularly among women. One study published in 2002 found that adequate vitamin C intake in women under 60 years of age reduced their risk of developing cataracts by 57%.
• Collagen production. Vitamin C assists the body in the manufacture of collagen, a protein that binds cells together and is the building block of connective tissues throughout the body. Collagen is critical to the formation and ongoing health of the skin, cartilage, ligaments, corneas, and other bodily tissues and structures. Vitamin C is also thought to promote faster healing of wounds and injuries because of its role in collagen production.
• Diabetes control. Vitamin C supplementation may assist diabetics in controlling blood sugar levels and improving metabolism.
• Gallbladder disease prevention. A study of over 13,000 subjects published in the Archives in Internal Medicine found that women who took daily vitamin C supplements were 34% less likely to contract gallbladder disease and gallstones , and that women deficient in ascorbic acid had an increased prevalence of gallbladder disease.
• Immune system booster. Vitamin C increases white blood cell production and is important to immune system balance. Studies have related low vitamin C levels to increased risk for infection. Vitamin C is frequently prescribed for HIV-positive individuals to protect their immune system.
• Neurotransmitter and hormone building. Vitamin C is critical to the conversion of certain substances into neurotransmitters, brain chemicals that facilitate the transmission of nerve impulses across a synapse (the space between neurons, or nerve cells). Such neurotransmitters as serotonin, dopamine, and norepinephrine are responsible for the proper functioning of the central nervous system, and a deficiency of neurotransmitters can result in psychiatric illness. Vitamin C also helps the body manufacture adrenal hormones.

Other benefits of vitamin C are less clear cut and have been called into question with conflicting study results. These include vitamin C's role in treating the common cold , preventing heart disease , and treating cancer.

Respiratory health

Doses of vitamin C may reduce the duration and severity of cold symptoms, particularly in people who are vitamin C deficient. The effectiveness of vitamin C therapy on colds seems to be related to the person's dietary vitamin C intake and their general health and lifestyle. In addition, however, other researchers have found that vitamin C is associated with improved lung function and overall respiratory health.

Heart disease prevention

Some studies have indicated that vitamin C may prevent heart disease by lowering total blood cholesterol and LDL cholesterol and raising HDL, or good cholesterol, levels. The antioxidant properties of vitamin C have also been associated with protection of the arterial lining in patients with coronary artery disease. A study published in 2002 reported that the protective effects of vitamin C on the lining of the arteries reduces the risk of heart disease in patients who have received heart transplants.

On the other hand, the results of a recent study conducted at the University of Southern California and released in early 2000 have cast doubt on the heart protective benefits of vitamin C. The study found that daily doses of 500 mg of vitamin C resulted in a thickening of the arteries in study subjects at a rate 2.5 times faster than normal. Thicker arterial walls can cause narrow blood vessels and actually increase the risk for heart disease. Study researchers have postulated that the collagen-producing effects of vitamin C could be the cause behind the arterial thickening. Further studies will be needed to determine the actual risks and benefits of vitamin C in relation to heart disease and to establish what a beneficial dosage might be, if one exists. For the time being, it is wise for most individuals, particularly those with a history of heart disease, to avoid megadoses over 200 mg because of the risk of arterial thickening.

Blood pressure control

A 1999 study found that daily doses of 500 mg of vitamin C reduced blood pressure in a group of 39 hypertensive individuals. Scientists have hypothesized that vitamin C may improve high blood pressure by aiding the function of nitric oxide, a gas produced by the body that allows blood vessels to dilate and facilitates blood flow. Again, recent findings that vitamin C may promote arterial wall thickening seem to contradict these findings, and further long-term studies are needed to assess the full benefits and risks of vitamin C in relation to blood pressure control.

Cancer treatment

Researchers disagree on the therapeutic use of vitamin C in cancer treatment. On one hand, studies have shown that tumors and cancer cells absorb vitamin C at a faster rate than normal cells because they have lost the ability to transport the vitamin. In addition, radiation and chemotherapy work in part by stimulating oxidation and the growth of free radicals in order to stop cancer cell growth. Because vitamin C is an antioxidant, which absorbs free radicals and counteracts the oxidation process, some scientists believe it could be counterproductive to cancer treatments. The exact impact vitamin C has on patients undergoing chemotherapy and other cancer treatments is not fully understood, and for this reason many scientists believe that vitamin C should be avoided by patients undergoing cancer treatment.

On the other side of the debate are researchers who believe that high doses of vitamin C can protect normal cells and inhibit the growth of cancerous ones. In labbased, in vitro studies, cancer cells were killed and/or stopped growing when large doses of vitamin C were administered. Researchers postulate that unlike normal healthy cells, which will take what they need of a vitamin and then discard the rest, cancer cells continue to absorb antioxidant vitamins at excessive rates until the cell structure is effected, the cell is killed, or cell growth simply stops. However, it is important to note that there have been no in vivo controlled clinical studies to prove this theory.

Based on the currently available controlled clinical data, cancer patients should avoid taking vitamin C supplementation beyond their recommended daily allowance.

Preparations

The U.S. recommended dietary allowance (RDA) of vitamin C was changed in 2000 to reflect growing recognition of the importance of vitamin C in the diet as an antioxidant as well as a protection against deficiency. The new values are as follows:

• men: 90 mg
• women: 75 mg
• pregnant women: 80 mg
• lactating women: 95 mg
• smokers: should consume an additional 35 mg

The National Academy of Sciences also established for the first time an upper limit (UL), or maximum daily dose, of 2,000 mg. Daily values for the vitamin as recommended by the U.S. Food and Drug Administration, the values listed on food and beverage labeling, remain at 60 mg for both men and women age four and older.

Many fruits and vegetables, including citrus fruits and berries, are rich in vitamin C. Foods rich in vitamin C include raw red peppers (174 mg/cup), guava (165 mg/fruit), orange juice (124 mg/cup), and black currants (202 mg/cup). Rose hips, broccoli, tomatoes, strawberries, papaya, lemons, kiwis, and brussels sprouts are also good sources of vitamin C. Eating at least five to nine servings of fruits and vegetables daily should provide adequate vitamin C intake for most people. Fresh, raw fruits and vegetables contain the highest levels of the vitamin. Both heat and light can reduce vitamin C potency in fresh foods, so overcooking and improper storage should be avoided. Sliced and chopped foods have more of their surface exposed to light, so keeping vegetables and fruits whole may also help to maintain full vitamin potency.

Vitamin C supplements are another common source of the vitamin. Individuals at risk for vitamin C depletion such as smokers, women who take birth control pills, and those with unhealthy dietary habits may benefit from a daily supplement. Supplements are available in a variety of different forms including pills, capsules, powders, and liquids. Vitamin C formulas also vary. Common compounds include ascorbic acid, calcium ascorbate, sodium ascorbate, and C complex. The C complex compound contains a substance called bioflavonoids , which may enhance the benefits of vitamin C. Vitamin C is also available commercially as one ingredient of a multivitamin formula.

The recommended daily dosage of vitamin C varies by individual need, but an average daily dose might be 200 mg. Some healthcare providers recommend megadoses (up to 40 g) of vitamin C to combat infections. However, the efficacy of these megadoses has not been proven, and in fact, some studies have shown that doses above 200 mg are not absorbed by the body and are instead excreted.

Precautions

Overdoses of vitamin C can cause nausea, diarrhea , stomach cramps, skin rashes , and excessive urination.

Because of an increased risk of kidney damage, persons with a history of kidney disease or kidney stones should never take dosages above 200 mg daily, and should consult with their healthcare provider before starting vitamin C supplementation.

A 1998 study linked overdoses (above 500 mg) of vitamin C to cell and DNA damage. However, other studies have contradicted these findings, and further research is needed to establish whether high doses of vitamin C can cause cell damage.

Side effects

Vitamin C can cause diarrhea and nausea. In some cases, side effects may be decreased or eliminated by adjusting the dosage of vitamin C.

Interactions

Vitamin C increases iron absorption, and is frequently prescribed with or added to commercial iron supplements for this reason.

Individuals taking anticoagulant, or blood thinning, medications should speak with their doctor before taking vitamin C supplements, as large doses of vitamin C may impact their efficacy.

Large amounts of vitamin C may increase estrogen levels in women taking hormone supplements or birth control medications, especially if both the supplement and the medication are taken simultaneously. Women should speak with their doctor before taking vitamin C if they are taking estrogen-containing medications. Estrogen actually decreases absorption of vitamin C, so larger doses of vitamin C may be necessary. A healthcare provider can recommend proper dosages and the correct administration of medication and supplement.

Persons who take aspirin, antibiotics, and/or steroids should consult with their healthcare provider about adequate dosages of vitamin C. These medications can increase the need for higher vitamin C doses.

Large dosages of vitamin C can cause a false-positive result in tests for diabetes.

Resources

BOOKS

Reavley, Nocola. The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs. New York: M. Evans & Company, 1998.

PERIODICALS

du Plessis, A. S., H. Randall, E. Escreet, et al. "Nutritional Status of Renal Transplant Patients." South African Medical Journal 92 (January 2002): 68-74.

Fang, J. C., S. Kinlay, J. Beltrame, et al. "Effect of Vitamins C and E on Progression of Transplant-Associated Arteriosclerosis: A Randomised Trial." Lancet 359 (March 30, 2002): 1108-1113.

Henderson, C.W. "Prevalence Lower in Women with Increased Vitamin C Levels." Women's Health Weekly (April 22, 2000): 7.

Jacob, R. A., and G. Sotoudeh. "Vitamin C Function and Status in Chronic Disease." Nutrition in Clinical Care 5 (March-April 2002): 66-74.

Leibman, Bonnie. "Antioxidants." Nutrition Action Health Letter (June 2000):9.

Morena, M., J. P. Cristol, J. Y. Bosc, et al. "Convective and Diffusive Losses of Vitamin C During Haemodiafiltration Session: A Contributive Factor to Oxidative Stress in Haemodialysis Patients." Nephrology Dialysis Transplantation 17 (March 2002): 422-427.

"New Questions About the Safety of Vitamin C Pills." Tufts University Health & Nutrition Letter (April 2000): 1.

Schunemann, H. J., S. McCann, B. J. Grant, et al. "Lung Function in Relation to Intake of Carotenoids and Other Antioxidant Vitamins in a Population-Based Study." American Journal of Epidemiology 155 (March 1, 2002): 463-471.

Taylor, A., P. F. Jacques, L. T. Chylack, Jr., et al. "Long-Term Intake of Vitamins and Carotenoids and Odds of Early Age-Related Cortical and Posterior Subcapsular Lens Opacities." American Journal of Clinical Nutrition 75 (March 2002): 540-549.

Tsuchiya, M., A. Asada, E. Kasahara, et al. "Smoking a Single Cigarette Rapidly Reduces Combined Concentrations of Nitrate and Nitrite and Concentrations of Antioxidants in Plasma." Circulation 105 (March 12, 2002): 1155-1157.

ORGANIZATIONS

United States Department of Agriculture. Center for Nutrition Policy and Promotion. 1120 20th Street NW, Suite 200, North Lobby, Washington, D.C. 20036. (202) 418–2312. http://www.usda.gov/cnpp/. john.webster@usda.gov.

Paula Ford-Martin

Rebecca J. Frey, PhD

KEY TERMS

In vivo testing

—A test performed on a living organism, such as a controlled clinical study involving human test subjects. In vivo is Latin for "in the living body."

Vitamin C

Definition

Purpose

Description

Precautions

Interactions

Complications

Parental concerns

Resources

Definition

Vitamin C, also called ascorbic acid or antiscorbutic vitamin, is a water-soluble organic compound needed to prevent scurvy. Scurvy is marked by beeding gums and bone malformation in children. Humans cannot make or store vitamin C, so they must get a steady supply of it from foods in their diet.

Purpose

Vitamin C is a powerful antioxidant that helps protect cells from damage. Vitamin C also is needed to make and repair collagen, move fat into cells where it can be converted into energy, and make neurotransmitters. There are also disputed claims that vitamin C, taken in large quantities as a dietary supplement, can prevent

Vitamin C

(Illustration by GGS Information Services/Thomson Gale.)

cancer, heart disease, the common cold, cataracts, and many other diseases.

High dose vitamin C may be used to treat or prevent urinary tract infections. High levels of vitamin C increase the acidity of urine, creating an unhospitable environment for bacteria growing in the urinary tract.

Description

Long before people knew what vitamin C was, they understood that eating certain foods, especially citrus fruit, would prevent a severe disease called scurvy. Vitamin C turned out to be the essential health-promoting compound in these foods. This vitamin was isolated in the early 1930s, and by 1934, a synthetic version of vitamin C was produced by the pharmaceutical company Hoffman-La Roche.

All animals need Vitamin C, but most animals can make their own. However, humans, along with apes, guinea pigs, and a few other animals, have lost that ability. In humans, this occurs because of a gene mutation thatcontrolsanenzyme neededtomake vitamin C. As a result, humans are completely dependent on getting enough of the vitamin from foods in their diet. In addition, vitamin C cannot be stored in the body. It is a water-soluble vitamin, and any amount that cannot be used immediately is excreted in urine. Vitamin C is not evenly distributed throughout the body. The adrenal glands, pituitary gland, thymus, retina, brain, spleen, lungs, liver, thyroid, testicles, lymph nodes, kidney, and pancreas all contain much higher levels of vitamin C than are found in circulating blood.

Vitamin C's role in health

Vitamin C functions as an antioxidant and as a coenzyme. Molecules called free radicals are formed during normal cell metabolism and with exposure to ultraviolet light or toxins such as cigarette smoke. Free radicals cause damage by reacting with fats and proteins in cell membranes and genetic material. This process is called oxidation. Antioxidants like vitamin C are compounds that attach themselves to free radicals so that it is impossible for the free radical to react with, or oxidize, other molecules. In this way, antioxidants protect cells from damage. The antioxidant properties of vitamin C are the basis for many of the controversial health claims made for it.

Vitamin C also functions as a coenzyme. Coen-zymes are small molecules that make it possible for metabolic activities to occur in cells. They are needed to break down food into its building-block molecules, build up new molecules from these building blocks, and convert nutrients into energy in cells. Vitamin C functions as a coenzyme in reactions that create collagen. Collagen is a protein that is found in cartilage, ligaments, tendons, bones, skin, and blood vessels. Vitamin C also is required to make the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Neurotransmitters are molecules that carry chemical messages from one nerve to another. Epinephrine is also made in the adrenal gland in response to stress. It prepares the body for a fight or flight response. Vitamin C may also be involved in cholesterol metabolism.

Normal vitamin C requirements

The United States Institute of Medicine (IOM ) of the National Academy of Sciences has developed values called Dietary Reference Intakes (DRI s) for vitamins and minerals. The DRIs consist of three sets of numbers. The Recommended Dietary Allowance (RDA ) defines the average daily amount of the nutrient needed to meet the health needs of 97–98% of the population. The Adequate Intake (AI) is an estimate set when there is not enough information to determine an RDA. The Tolerable Upper Intake Level (UL) is the average maximum amount that can be

KEY TERMS

Alzheimer's disease —An incurable disease of older individuals that results in the destruction of nerve cells in the brain and causes gradual loss of mental and physical functions.

Antioxidant —A molecule that prevents oxidation. In the body antioxidants attach to other molecules called free radicals and prevent the free radicals from causing damage to cell walls, DNA, and other parts of the cell.

Coenzyme —Also called a cofactor, a small non-protein molecule that binds to an enzyme and helps regulate enzyme-mediated reactions.

Collagen —A long fiber-like protein found in skin, bones, blood vessels, and connective tissue such as tendons and ligaments.

Conventional medicine —Mainstream or Western pharmaceutical-based medicine practiced by medical doctors, doctors of osteopathy, and other licensed health care professionals.

Dietary supplement —A product, such as a vitamin, mineral, herb, amino acid, or enzyme, that is intended to be consumed in addition to an individual's diet with the expectation that it will improve health.

Enzyme —A protein that change the rate of a chemical reaction within the body without themselves being used up in the reaction.

Neurotransmitter —One of a group of chemicals secreted by a nerve cell (neuron) to carry a chemical message to another nerve cell, often as a way of transmitting a nerve impulse. Examples of neurotransmitters include acetylcholine, dopamine, serotonin, and norepinephrine.

Osteoporosis —A condition found in older individuals in which bones decrease in density and become fragile and more likely to break. It can be caused by lack of vitamin D and/or calcium in the diet.

Placebo —A pill or liquid given during the study of a drug or dietary supplement that contains no medication or active ingredient. Usually study participants do not know if they are receiving a pill containing the drug or an identical-appearing placebo.

Toxin —A general term for something that harms or poisons the body.

Vitamin —A nutrient that the body needs in small amounts to remain healthy but that the body cannot manufacture for itself and must acquire through diet.

Water-soluble vitamin —A vitamin that dissolves in water and can be removed from the body in urine.

taken daily without risking negative side effects. The DRI s are calculated for children, adult men, adult women, pregnant women, and breastfeeding women.

The IOM has not set RDA s for vitamin C in children under one year old because of incomplete scientific information. Instead, it has set AI levels for this age group. RDA2s and ULs for vitamin C are measured in milligrams (mg). The RDAs and ULs set by the IOM are highly controversial. They are set at a level based on preventing scurvy. Many researchers believe that doses hundreds of times higher are needed to prevent certain chronic diseases. They argue that large doses of vitamin C have minimal side effects and that RDAs and ULs should be much higher. These researchers suggest of anywhere from 400-3,000 mg per day for health adults.

The following lit gives the daily RDAs and IAs and ULs for vitamin C for healthy individuals as established by the IOM.

• children birth-6 months: AI 40 mg; UL not established; All vitamin C should come from breast milk, fortified formula, or food. children 7-12 months: AI 50 mg; UL not established; All vitamin C should come from breast milk, fortified formula, or food.
• children 1-3 years: RDA 15 mg; UL 400 mg
• children 4-8 years: RDA 25 mg; UL 650 mg
• children 9-13 years: RDA 45 mg; UL 1,200 mg
• boys 14-18 years: RDA 75 mg; UL 1,800 mg
• girls 14-18 years: RDA 65 mg; UL 1,800 mg
• men age 19 and older: RDA 90 mg; UL 2,000 mg
• women age 19 and older: RDA 75 mg; UL 2,000 mg
• men who smoke: RDA 125 mg; UL 2,000 mg
• women who smoke: RDA 110 mg; UL 2,000 mg
• pregnant women 18 years and younger: RDA 80 mg; UL 1,800 mg
• pregnant women 19 years and older: RDA 85 mg; UL 2,000 mg
• breastfeeding women 19 years and older: RDA 120 mg; 2,000 mg

Vitamin C is the most commonly taken dietary supplement taken by Americans. As a single-ingredient supplement, it is available as tablets, capsules, and powder. It is found in multivitamin and antiox-idant supplements. It is also combined with minerals such as calcium (e.g. Ester-C) to make it less acidic and thus less irritating to the stomach in large doses. Vitamin C can be made synthetically or derived from corn or palm oil (ascorbyl palmate). There is little evidence that one form is more effective than another. Vitamin C is added to some skin creams, throat lozenges, energy drinks, and energy bars, and to some processed foods. In 2007, the two largest American soft drink manufacturers announced that they were going to produce carbonated drinks fortified with vitamins and minerals, including vitamin C.

Vitamin C deficiency produces a disease called scurvy. From the earliest times, scurvy was a problem for sailors on long voyages where there was no way to store fresh fruits and vegetables. In 1746, a doctor in the British navy proved that eating lemons and oranges could prevent scurvy among sailors. Early Spanish explorers planted orange trees in Florida and the Caribbean so that they would have a source of oranges to prevent scurvy on their long voyages back to Europe. Today scurvy occurs infrequently. As little as 10 mg per day of vitamin C can prevent the disease. People with alcoholism, elderly individuals on extremely restricted diets, and malnourished infants in developing countries are at higher risk for developing scurvy. Symptoms include fatigue, easy bruising, excessive bleeding, hair loss, sore gums, tooth loss, and joint pain. Left untreated, death can occur, usually through sudden cardiac attack. Smoking increases the body's need for vitamin C, but is not, by itself, a cause of scurvy.

Sources of vitamin C

People need a continuous supply of vitamin C from their diet because of the role it plays in many metabolic processes. Vitamin C is found in many foods. Good natural sources of vitamin C include citrus fruits and their juices, papaya, red bell peppers, broccoli, and tomatoes.

Vitamin C is unstable and is lost when food is exposed to air, temperature changes, and water. About one-quarter of the vitamin C content of vegetables is lost by brief boiling, steaming, or freezing and thawing. Canning fruits and vegetables reduces their vitamin C content by about one-third, as does longer cooking at higher temperatures. However, both the American Cancer Society and the American Heart Association recommend that people meet their vitamin C (and many other vitamin requirements) through a healthy diet that includes eating a minimum of 5 servings of fruits and vegetables daily.

The following list gives the approximate vitamin C content for some common foods:

• orange, 1 medium: 70 mg
• orange juice, ¾ cup (6 ounces): 75 mg
• grapefruit, ½ medium: 44 mg
• grapefruit juice, ¾ cup (6 ounces): 60 mg
• strawberries, 1 cup: 82 mg
• papaya, 1: 94 mg
• tomato, 1 medium: 23 mg
• red bell pepper, ½ cup raw: 141 mg
• broccoli, steamed, ½ cup: 62 mg
• cauliflower, boiled, ½ cup: 27 mg
• potato, 1 medium, baked: 26 mg

Controversial health claims for vitamin C

Controversy about vitamin C centers on its usefulness in preventing or treating disease when taken in very large quantities as a dietary supplement. Most of these claims have not been substantiated by well-designed, well-controlled studies. Many are still being investigated in government-sponsored clinical trials. Individuals interested in participating in a clinical trial at no charge can find a list of open trials at http://www.clinicaltrials.gov.

COLDS. Nobel prize-winning chemist Linus Pauling popularized the idea that large doses (1,000 mg or more) of vitamin C daily, will prevent, shorten the duration, or reduce the severity of symptoms of the common cold. More than 30 trials have compared colds in people taking up to 2,000 mg of vitamin C daily and those taking a placebo (pill with no nutritional value). These studies found no difference in the number or severity of colds in the two groups, with one exception. Skiers, marathon runners, and soldiers training in Arctic conditions who took vitamin C supplements had 50% fewer colds than people who took no extra vitamin C. All the people who benefited from taking vitamin C supplements were putting their bodies under extreme stress. It appears that for elite athletes and others under physical stress, dietary supplements of vitamin C may be of value in preventing colds.

CANCER. Cancer is thought to arise because of damage to cells caused by free radicals. Health claims that vitamin C prevents cancer are based on its antioxidant properties. Many studies have shown that people who eat a diet low in fats and high in fresh fruits and vegetables have a lower risk of developing cancer, especially cancer of the mouth, esophagus, stomach, colon, and lung. It is not clear that the benefit of this diet is due to vitamin C. Study results using dietary supplements of vitamin C are mixed. The American Cancer Society recommends increasing healthy foods in the diet to reduce cancer risk rather than taking a dietary supplement.

CARDIOVASCULAR HEALTH. Because vitamin C is involved in the production of collagen in blood vessels, researchers have examined the relationship between vitamin C intake and cardiovascular health. Some studies found no benefit to vitamin C supplementation, while others reported that a relatively low dose of vitamin C reduced the risk of death from strokes. Vitamin C does not reduce blood levels of cholesterol. The American Heart Association recommends that to improve cardiovascular health individuals should increase their intake of vitamin C (and other vitamins and mineral) by increasing the amount of fresh vegetables in their diet. Research continues in this area.

CATARACTS. Cataracts are the leading cause of vision impairment worldwide. They develop, usually in older individuals, because of changes in the proteins in the lens of the eye. Initial studies suggested that vitamin C could prevent these changes because of its antioxidant properties. A recent a 7-year follow-up study found vitamin C supplements to be of no benefit in preventing cataracts.

OTHER HEALTH CLAIMS. Claims have been made that vitamin C can treat or prevent lead poisoning, high blood pressure (hypertension ), asthma, Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), infertility, macular degeneration, premature birth, stomach ulcers, autism, and many other diseases and disorders. None of these health claims have been proved to the satisfaction of practitioners of conventional medicine.

Precautions

People who smoke cigarettes need more vitamin C than those who do not. People with cancer also seem to need more vitamin C.

Large doses of vitamin C as a dietary supplement may cause indigestion or diarrhea that stops when the dose is reduced.

Interactions

Vitamin C has few interactions with drugs or other vitamins. Large doses of vitamin C increase the amount of iron absorbed from food in the small intestine. In healthy people, this does not cause any problems and may be beneficial.

Large daily doses of vitamin C may interfere with the absorption of vitamin B_12.

Complications

Vitamin C can be taken in enormous doses without any serious side effects. At very high doses, it causes diarrhea. Some researchers who believe that large doses of vitamin C prevent disease think that the appropriate daily dose is an amount just slightly less than the amount that causes diarrhea. This amount varies considerably form person to person.

Parental concerns

Generally, parents should have few concerns about children getting either too much or too little Vitamin C. Vitamin C is safe for women to take during pregnancy and while breastfeeding. It passes into breast milk. Children under age one should not be given a dietary supplement containing vitamin C; their needs should be met through the foods the eat.

Resources

BOOKS

Berkson, Burt and Arthur J. Berkson. Basic Health Publications User's Guide to the B-complex Vitamins. Laguna Beach, CA: Basic Health Publications, 2006.

Gaby, Alan R., ed. A-Z Guide to Drug-Herb-Vitamin Interactions Revised and Expanded 2nd Edition: Improve Your Health and Avoid Side Effects When Using Common Medications and Natural Supplements Together.-New York: Three Rivers Press, 2006.

Lieberman, Shari and Nancy Bruning. The Real Vitamin and Mineral Book: The Definitive Guide to Designing Your Personal Supplement Program, 4th ed. New York: Avery, 2007.

Peel, Thomas, ed. Vitamin C: New Research. New York: Nova Science Publishers, 2006.

Pressman, Alan H. and Sheila Buff. The Complete Idiot's Guide to Vitamins and Minerals, 3rd ed. Indianapolis, IN: Alpha Books, 2007.

Rucker, Robert B., ed. Handbook of Vitamins. Boca Raton, FL: Taylor & Francis, 2007.

PERIODICALS

Kushi, Lawrence H., Tim Byers, Colleen Doyle, et al.

American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention.&” CA: Cancer Journal for Clinicians, 56 (2006):254-281. <http://caonline.amcancersoc.org/cgi/content/full/56/5/254>

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road NE, Atlanta

GA 30329-4251. Telephone: 800 ACS-2345. Website:

<http://www.cancer.org>

American Heart Association. 7272 Greenville Avenue, Dallas, TX 75231. Telephone: (800) 242-8721. Website: <http://www.americanheart.org>

American Dietetic Association. 120 South Riverside Plaza, Suite 2000, Chicago, Illinois 60606-6995. Telephone: (800) 877-1600. Website: <http://www.eatright.org>

Linus Pauling Institute. Oregon State University, 571

Weniger Hall, Corvallis, OR 97331-6512. Telephone: (541) 717-5075. Fax: (541) 737-5077. Website: <http://lpi.oregonstate.edu>

Vitamin C Foundation. P. O. Box 73172, Houston, TX 77273. Telephone: (888) 443-3634 or (281) 443-3634. Website: <www.vitamincfoundation.org/found.htm>

OTHER

Higdon, Jane.“Vitamin C.” Linus Pauling Institute-Oregon State University, January 31 12, 2006. <http://lpi.oregonstate.edu/infocenter/vitamins/VitaminC>

Harvard School of Public Health.“Vitamins.” Harvard University, November 10, 2006. <http://www.hsph.harvard.edu/nutritionsource/vitamins.html>

Maryland Medical Center Programs Center for Integrative Medicine.“Vitamin C (Ascorbic Acid).” University ofMaryland Medical Center, April 2002. <http://www.umm.edu/altmed/ConsSupplements/VitaminCAscorbicAcidcs>

Medline Plus.“Vitamin C (Ascorbic Acid).” U. S. National Library of Medicine, August 1, 2006. <http://www.nlm.nih/gov/medlineplus/druginfo/natural/patient-vitaminc.html>

Rajakumar, Kumaravel.“Scurvy.” emedicine.com, August 15, 2006. <http://www.emedicine.com/med/topic.htm>

Tish Davidson, A.M.

Vitamin C

Definition

Vitamin C, also called ascorbic acid or antiscorbutic vitamin, is a water-soluble organic compound needed to prevent scurvy. Humans cannot make or store vitamin C, so they must get a steady supply of it from foods in their diet .

Purpose

Vitamin C is a powerful antioxidant that helps protect cells from damage. Vitamin C also is needed to make and repair collagen, move fat into cells where it can be converted into energy, and make neurotransmitters. There are also disputed claims that vitamin C, taken in large quantities as a dietary supplement, can prevent cancer, heart disease , the common cold, cataracts , and many other diseases.

High dose vitamin C may be used to treat or prevent urinary tract infections. High levels of vitamin C increase the acidity of urine, creating an unhospitable environment for bacteria growing in the urinary tract.

Description

Long before people knew what vitamin C was, they understood that eating certain foods, especially citrus fruit, would prevent a severe disease called scurvy. Vitamin C turned out to be the essential health-promoting compound in these foods. This vitamin was isolated in the early 1930s, and by 1934, a synthetic version of vitamin C was produced by the pharmaceutical company Hoffman-La Roche.

All animals need Vitamin C, but most animals can make their own. However, humans, along with apes, guinea pigs, and a few other animals, have lost that ability. In humans, this occurs because of a gene mutation that controls an enzyme needed to make vitamin C. As a result, humans are completely dependent on getting enough of the vitamin from foods in their diet. In addition, vitamin C cannot be stored in the body. It is a water-soluble vitamin, and any amount that cannot be used immediately is excreted in urine. Vitamin C is not evenly distributed throughout the body. The adrenal glands, pituitary gland, thymus, retina, brain, spleen, lungs, liver, thyroid, testicles, lymph nodes, kidney, and pancreas all contain much higher levels of vitamin C than are found in circulating blood.

Vitamin C's role in health

Vitamin C functions as an antioxidant and as a coenzyme. Molecules called free radicals are formed during normal cell metabolism and with exposure to ultraviolet light or toxins such as cigarette smoke. Free radicals cause damage by reacting with fats and proteins in cell membranes and genetic material. This process is called oxidation. Antioxidants like vitamin C are compounds that attach themselves to free radicals so that it is impossible for the free radical to react with, or oxidize, other molecules. In this way, antioxidants protect cells from damage. The antioxidant properties of vitamin C are the basis for many of the controversial health claims made for it.

Vitamin C also functions as a coenzyme. Coenzymes are small molecules that make it possible for metabolic activities to occur in cells. They are needed to break down food into its building-block molecules, build up new molecules from these building blocks, and convert nutrients into energy in cells. Vitamin C functions as a coenzyme in reactions that create collagen. Collagen is a protein that is found in cartilage, ligaments, tendons, bones, skin, and blood vessels. Vitamin C also is required to make the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Neurotransmitters are molecules that carry chemical messages from one nerve to another. Epinephrine is also made in the adrenal gland in response to stress. It prepares the body for a fight or flight response. Vitamin C may also be involved in cholesterol metabolism.

Normal vitamin C requirements

The United States Institute of Medicine (IOM) of the National Academy of Sciences has developed values called Dietary Reference Intakes (DRIs) for vitamins and minerals. The DRIs consist of three sets of numbers. The Recommended Dietary Allowance (RDA) defines the average daily amount of the nutrient needed to meet the health needs of 97–98% of the population. The Adequate Intake (AI) is an estimate set when there is not enough information to determine an RDA. The Tolerable Upper Intake Level (UL) is the average maximum amount that can be taken daily without risking negative side effects.

The following lit gives the daily RDAs and IAs and ULs for vitamin C for healthy individuals as established by the IOM.

• men age 19 and older: RDA 90 mg; UL 2,000 mg
• women age 19 and older: RDA 75 mg; UL 2,000 mg
• men who smoke: RDA 125 mg; UL 2,000 mg
• women who smoke: RDA 110 mg; UL 2,000 mg

Vitamin C is the most commonly taken dietary supplement taken by Americans. As a single-ingredient supplement, it is available as tablets, capsules, and powder. It is found in multivitamin and antioxidant supplements. It is also combined with minerals such as calcium (e.g. Ester-C) to make it less acidic and thus less irritating to the stomach in large doses. Vitamin C can be made synthetically or derived from corn or palm oil (ascorbyl palmate). There is little evidence that one form is more effective than another. Vitamin C is added to some skin creams, throat lozenges, energy drinks, and energy bars, and to some processed foods. In 2007, the two largest American soft drink manufacturers announced that they were going to produce carbonated drinks fortified with vitamins and minerals, including vitamin C.

Vitamin C deficiency produces a disease called scurvy. From the earliest times, scurvy was a problem for sailors on long voyages where there was no way to store fresh fruits and vegetables. In 1746, a doctor in the British navy proved that eating lemons and oranges could prevent scurvy among sailors. Early Spanish explorers planted orange trees in Florida and the Caribbean so that they would have a source of oranges to prevent scurvy on their long voyages back to Europe. Today scurvy occurs infrequently. As little as 10 mg per day of vitamin C can prevent the disease. People with alcoholism, elderly individuals on extremely restricted diets, and malnourished infants in developing countries are at higher risk for developing scurvy. Symptoms include fatigue, easy bruising , excessive bleeding, hair loss, sore gums, tooth loss, and joint pain . Left untreated, death can occur, usually through sudden cardiac attack. Smoking increases the body&s need for vitamin C, but is not, by itself, a cause of scurvy.

KEY TERMS

Alzheimer's disease —An incurable disease of older individuals that results in the destruction of nerve cells in the brain and causes gradual loss of mental and physical functions.

Antioxidant —A molecule that prevents oxidation. In the body antioxidants attach to other molecules called free radicals and prevent the free radicals from causing damage to cellwalls, DNA, and other parts of the cell.

Coenzyme —Also called a cofactor, a small non-protein molecule that binds to an enzyme and helps regulate enzyme-mediated reactions.

Collagen —A long fiber-like protein found in skin, bones, blood vessels, and connective tissue such as tendons and ligaments.

Conventional medicine —Mainstream or Western pharmaceutical-based medicine practiced by medical doctors, doctors of osteopathy, and other licensed health care professionals.

Dietary supplement —A product, such as a vitamin, mineral, herb, amino acid, or enzyme, that is intended to be consumed in addition to an individual's diet with the expectation that it will improve health.

Enzyme —A protein that change the rate of a chemical reaction within the body without themselves being used up in the reaction.

Neurotransmitter —One of a group of chemicals secreted by a nerve cell (neuron) to carry a chemical message to another nerve cell, often as a way of transmitting a nerve impulse. Examples of neurotransmitters include acetylcholine, dopamine, serotonin, and norepinephrine.

Osteoporosis —A condition found in older individuals in which bones decrease in density and become fragile and more likely to break. It can be caused by lack of vitamin D and/or calcium in the diet.

Placebo —A pill or liquid given during the study of a drug or dietary supplement that contains no medication or active ingredient. Usually study participants do not know if they are receiving a pill containing the drug or an identical-appearing placebo.

Toxin —A general term for something that harms or poisons the body.

Vitamin —A nutrient that the body needs in small amounts to remain healthy but that the body cannot manufacture for itself and must acquire through diet.

Water-soluble vitamin —A vitamin that dissolves in water and can be removed from the body in urine.

Sources of vitamin C

People need a continuous supply of vitamin C from their diet because of the role it plays in many metabolic processes. Vitamin C is found in many foods. Good natural sources of vitamin C include citrus fruits and their juices, papaya, red bell peppers, broccoli, and tomatoes.

Vitamin C is unstable and is lost when food is exposed to air, temperature changes, and water. About one-quarter of the vitamin C content of vegetables is lost by brief boiling, steaming, or freezing and thawing. Canning fruits and vegetables reduces their vitamin C content by about one-third, as does longer cooking at higher temperatures. However, both the American Cancer Society and the American Heart Association recommend that people meet their vitamin C (and many other vitamin requirements) through a healthy diet that includes eating a minimum of 5 servings of fruits and vegetables daily.

The following list gives the approximate vitamin C content for some common foods:

• orange, 1 medium: 70 mg
• orange juice, 3/4 cup (6 ounces): 75 mg
• grapefruit, 1/2 medium: 44 mg
• grapefruit juice, 3/4 cup (6 ounces): 60 mg
• strawberries, 1 cup: 82 mg
• papaya, 1: 94 mg
• tomato, 1 medium: 23 mg
• red bell pepper, 1/2 cup raw: 141 mg
• broccoli, steamed, 1/2 cup: 62 mg
• cauliflower, boiled, 1/2 cup: 27 mg
• potato, 1 medium, baked: 26 mg

Controversial health claims for vitamin C

Controversy about vitamin C centers on its usefulness in preventing or treating disease when taken in very large quantities as a dietary supplement. Most of these claims have not been substantiated by well-designed, well-controlled studies. Many are still being investigated in government-sponsored clinical trials. Individuals interested in participating in a clinical trial at no charge can find a list of open trials at http://www.clinicaltrials.gov.

colds Nobel prize-winning chemist Linus Pauling popularized the idea that large doses (1,000 mg or more) of vitamin C daily, will prevent, shorten the duration, or reduce the severity of symptoms of the common cold. More than 30 trials have compared colds in people taking up to 2,000 mg of vitamin C daily and those taking a placebo (pill with no nutritional value). These studies found no difference in the number or severity of colds in the two groups, with one exception. Skiers, marathon runners, and soldiers training in Arctic conditions who took vitamin C supplements had 50% fewer colds than people who took no extra vitamin C. All the people who benefited from taking vitamin C supplements were putting their bodies under extreme stress. It appears that for elite athletes and others under physical stress, dietary supplements of vitamin C may be of value in preventing colds.

cancer Cancer is thought to arise because of damage to cells caused by free radicals. Health claims that vitamin C prevents cancer are based on its antioxidant properties. Many studies have shown that people who eat a diet low in fats and high in fresh fruits and vegetables have a lower risk of developing cancer, especially cancer of the mouth, esophagus, stomach, colon, and lung. It is not clear that the benefit of this diet is due to vitamin C. Study results using dietary supplements of vitamin C are mixed. The American Cancer Society recommends increasing healthy foods in the diet to reduce cancer risk rather than taking a dietary supplement.

cardiovascular health Because vitamin C is involved in the production of collagen in blood vessels, researchers have examined the relationship between vitamin C intake and cardiovascular health. Some studies found no benefit to vitamin C supplementation, while others reported that a relatively low dose of vitamin C reduced the risk of death from strokes. Vitamin C does not reduce blood levels of cholesterol. The American Heart Association recommends that to improve cardiovascular health individuals should increase their intake of vitamin C (and other vitamins and mineral) by increasing the amount of fresh vegetables in their diet. Research continues in this area.

cataracts Cataracts are the leading cause of vision impairment worldwide. They develop, usually in older individuals, because of changes in the proteins in the lens of the eye. Initial studies suggested that vitamin C could prevent these changes because of its antioxidant properties. A recent a 7-year follow-up study found vitamin C supplements to be of no benefit in preventing cataracts.

other health claims Claims have been made that vitamin C can treat or prevent lead poisoning, high blood pressure (hypertension ), asthma , Alzheimer's disease, macular degeneration, premature birth, stomach ulcers, autism, and many other diseases and disorders. None of these health claims have been proved to the satisfaction of practitioners of conventional medicine.

Precautions

People who smoke cigarettes need more vitamin C than those who do not. People with cancer also seem to need more vitamin C.

Large doses of vitamin C as a dietary supplement may cause indigestion or diarrhea that stops when the dose is reduced.

Interactions

Vitamin C has few interactions with drugs or other vitamins. Large doses of vitamin C increase the amount of iron absorbed from food in the small intestine. In healthy people, this does not cause any problems and may be beneficial.

Large daily doses of vitamin C may interfere with the absorption of vitamin B ₁₂.

Complications

Vitamin C can be taken in enormous doses without any serious side effects. At very high doses, it causes diarrhea. Some researchers who believe that large doses of vitamin C prevent disease think that the appropriate daily dose is an amount just slightly less than the amount that causes diarrhea. This amount varies considerably form person to person.

Resources

BOOKS

Berkson, Burt and Arthur J. Berkson. Basic Health Publications User&s Guide to the B-complex Vitamins. Laguna Beach, CA: Basic Health Publications, 2006.

Gaby, Alan R., ed. A-Z Guide to Drug-Herb-Vitamin Interactions Revised and Expanded 2nd Edition: Improve Your Health and Avoid Side Effects When Using Common Medications and Natural Supplements Together. New York: Three Rivers Press, 2006.

Lieberman, Shari and Nancy Bruning. The Real Vitamin and Mineral Book: The Definitive Guide to Designing Your Personal Supplement Program, 4th ed. New York: Avery, 2007.

Peel, Thomas, ed. Vitamin C: New Research. New York: Nova Science Publishers, 2006.

Pressman, Alan H. and Sheila Buff. The Complete Idiot's Guide to Vitamins and Minerals, 3rd ed. Indianapolis, IN: Alpha Books, 2007.

Rucker, Robert B., ed. Handbook of Vitamins. Boca Raton, FL: Taylor & Francis, 2007.

PERIODICALS

Kushi, Lawrence H., Tim Byers, Colleen Doyle, et al. “American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention.” CA: Cancer Journal for Clinicians, 56 (2006): 254–281.

ORGANIZATIONS

Vitamin C Foundation, P. O. Box 73172, Houston, TX, 77273, (281) 443-3634, http://www.vitamincfoundation.org/found.htm.

Tish Davidson A.M.

Vitamin C

Description

Vitamin C, or ascorbic acid, is naturally produced in fruits and vegetables. The vitamin, which can be taken in dietary or supplementary form, is absorbed by the intestines. That which the body cannot absorb is excreted in the urine. The body stores a small amount, but daily intake, preferably in dietary form, is recommended for optimum health.

Certain health conditions may cause vitamin C depletion, including diabetes and high blood pressure. Individuals who smoke and women who take estrogen may also have lower vitamin C levels. In addition, men are more likely to be vitamin C depleted, as are the elderly. High stress levels have also been linked to vitamin C deficiency.

Severe vitamin C deficiency leads to scurvy, a disease common on ships prior to the sixteenth century, due to the lack of fresh fruits and other dietary vitamin C sources. Symptoms of scurvy include weakness, bleeding, tooth loss, bleeding gums, bruising, and joint pain. Less serious vitamin C depletion can have more subtle effects such as weight loss, fatigue, weakened immune system (as demonstrated by repeated infections and colds), bruises that occur with minor trauma and are slow to heal, and slow healing of other wounds.

Low vitamin C levels have also been associated with high blood pressure, increased heart attack risk, increased risk for developing cataracts, and a higher risk for certain types of cancer (i.e., prostate, stomach, colon, oral, and lung).

General use

Vitamin C is a critical component to both disease prevention and to basic body building processes. The therapeutic effects of vitamin C include:

• Allergy and asthma relief. Vitamin C is present in the lung's airway surfaces, and insufficient vitamin C levels have been associated with bronchial constriction and reduced lung function. Some studies have associated vitamin C supplementation with asthmatic symptom relief, but results have been inconclusive and further studies are needed.
• Cancer prevention. Vitamin C is a known antioxidant and has been associated with reduced risk of stomach, lung, colon, oral, and prostate cancer.
• Cataract prevention. Long-term studies on vitamin C supplementation and cataract development have shown that supplementation significantly reduces the risk for cataracts, particularly among women.
• Collagen production. Vitamin C assists the body in the manufacture of collagen, a protein that binds cells together and is the building block of connective tissues throughout the body. Collagen is critical to the formation and ongoing health of the skin, cartilage, ligaments, corneas, and other bodily tissues and structures. Vitamin C is also thought to promote faster healing of wounds and injuries because of its role in collagen production.
• Diabetes control. Vitamin C supplementation may assist diabetics in controlling blood sugar levels and improving metabolism.
• Gallbladder disease prevention. A study of over 13,000 subjects published in the Archives in Internal Medicine found that women who took daily vitamin C supplements were 34% less likely to contract gallbladder disease and gallstones, and that women deficient in ascorbic acid had an increased prevalence of gallbladder disease.
• Immune system booster. Vitamin C increases white blood cell production and is important to immune system balance. Studies have related low vitamin C levels to increased risk for infection. Vitamin C is frequently prescribed for HIV-positive individuals to protect their immune system.
• Neurotransmitter and hormone building. Vitamin C is critical to the conversion of certain substances into neurotransmitters, brain chemicals that facilitate the transmission of nerve impulses across a synapse (the space between neurons, or nerve cells). Neurotransmitters such as serotonin, dopamine, and norepinephrine are responsible for the proper functioning of the central nervous system, and a deficiency of neurotransmitters can result in psychiatric illness. Vitamin C also helps the body manufacture adrenal hormones.

Other benefits of vitamin C are less clear cut and have been called into question with conflicting study results. These include vitamin C's role in treating the common cold, preventing heart disease, and treating cancer.

Treating the common cold

Doses of vitamin C may reduce the duration and severity of cold symptoms, particularly in those individuals who are vitamin C deficient. The effectiveness of vitamin C therapy on colds seems to be related to the dietary vitamin C intake of the individual and the individual's general health and lifestyle.

Heart disease prevention

Some studies have indicated that vitamin C may prevent heart disease by lowering total blood cholesterol and LDL cholesterol and raising HDL, or good cholesterol, levels. The antioxidant properties of vitamin C have also been associated with protection of the arterial lining in patients with coronary artery disease.

However, the results of a recent study conducted at the University of Southern California and released in early 2000 have cast doubt on the heart protective benefits of vitamin C. The study found that daily doses of 500 mg of vitamin C resulted in a thickening of the arteries in study subjects at a rate 2.5 times faster than normal. Thicker arterial walls can cause narrow blood vessels and actually increase the risk for heart disease. Study researchers have postulated that the collagen producing effects of vitamin C could be the cause behind the arterial thickening. Further studies will be needed to determine the actual risks and benefits of vitamin C in relation to heart disease and to establish what a beneficial dosage might be, if one exists. For the time being, it is wise for most individuals, particularly those with a history of heart disease, to avoid megadoses over 200 mg because of the risk of arterial thickening.

Blood pressure control

A 1999 study found that daily doses of 500 mg of vitamin C reduced blood pressure in a group of 39 hypertensive individuals. Scientists have hypothesized that vitamin C may improve high blood pressure by aiding the function of nitric oxide, a gas produced by the body that allows blood vessels to dilate and facilitates blood flow. Again, recent findings that vitamin C may promote arterial wall thickening seem to contradict these findings, and further long-term studies are needed to assess the full benefits and risks of vitamin C in relation to blood pressure control.

Cancer treatment

Researchers disagree on the therapeutic use of vitamin C in cancer treatment. On one hand, studies have shown that tumors and cancer cells absorb vitamin C at a faster rate than normal cells because they have lost the ability to transport the vitamin. In addition, radiation and chemotherapy work in part by stimulating oxidation and the growth of free radicals in order to stop cancer cell growth. Because vitamin C is an antioxidant, which absorbs free radicals and counteracts the oxidation process, some scientists believe it could be counterproductive to cancer treatments. The exact impact vitamin C has on patients undergoing chemotherapy and other cancer treatments is not fully understood, and for this reason many scientists believe that vitamin C should be avoided by patients undergoing cancer treatment.

On the other side of the debate are researchers who believe that high doses of vitamin C can protect normal cells and inhibit the growth of cancerous ones. In lab-based, in vitro studies, cancer cells were killed and/or stopped growing when large doses of vitamin C were administered. Researchers postulate that unlike normal healthy cells, which will take what they need of a vitamin and then discard the rest, cancer cells continue to absorb antioxidant vitamins at excessive rates until the cell structure is effected, the cell is killed, or cell growth simply stops. However, it is important to note that there have been no in vivo controlled clinical studies to prove this theory.

Based on the currently available controlled clinical data, cancer patients should avoid taking vitamin C supplementation beyond their recommended daily allowance.

Preparations

The U.S. recommended dietary allowance (RDA) of vitamin C is as follows:

• men: 60 mg
• women: 60 mg
• pregnant women: 70 mg
• lactating women: 95 mg

In April 2000, the National Academy of Sciences recommended changing the RDA for vitamin C to 75 mg for women and 90 mg for men, with an upper limit(UL), or maximum daily dose, of 2,000 mg. Daily values for the vitamin as recommended by the U.S. Food and Drug Administration, the values listed on food and beverage labeling, remain at 60 mg for both men and women age four and older.

Many fruits and vegetables, including citrus fruits and berries, are rich in vitamin C. Foods rich in vitamin C include raw red peppers (174 mg/cup), guava(165 mg/fruit), orange juice (124 mg/cup), and black currants (202 mg/cup). Rose hips, broccoli, tomatoes, strawberries, papaya, lemons, kiwis, and brussels sprouts are also good sources of vitamin C. Eating at least five to nine servings of fruits and vegetables daily should provide adequate vitamin C intake for most people. Fresh, raw fruits and vegetables contain the highest levels of the vitamin. Both heat and light can reduce vitamin C potency in fresh foods, so overcooking and improper storage should be avoided. Sliced and chopped foods have more of their surface exposed to light, so keeping vegetables and fruits whole may also help to maintain full vitamin potency.

Vitamin C supplements are another common source of the vitamin. Individuals at risk for vitamin C depletion such as smokers, women who take birth control pills, and those with unhealthy dietary habits may benefit from a daily supplement. Supplements are available in a variety of different forms including pills, capsules, powders, and liquids. Vitamin C formulas also vary. Common compounds include ascorbic acid, calcium ascorbate, sodium ascorbate, and C complex. The C complex compound contains a substance called bioflavonoids, which may enhance the benefits of vitamin C. Vitamin C is also available commercially as one ingredient of a multivitamin formula.

The recommended daily dosage of vitamin C varies by individual need, but an average daily dose might be 200 mg. Some healthcare providers recommend megadoses (up to 40 g) of vitamin C to combat infections. However, the efficacy of these megadoses has not been proven, and in fact, some studies have shown that doses above 200 mg are not absorbed by the body and are instead excreted.

Precautions

Overdoses of vitamin C can cause nausea, diarrhea, stomach cramps, skin rashes, and excessive urination.

Because of an increased risk of kidney damage, individuals with a history of kidney disease or kidney stones should never take dosages above 200 mg daily, and should consult with their healthcare provider before starting vitamin C supplementation.

A 1998 study linked overdoses (above 500 mg) of vitamin C to cell and DNA damage. However, other studies have contradicted these findings, and further research is needed to establish whether high doses of vitamin C can cause cell damage.

Side effects

Vitamin C can cause diarrhea and nausea. In some cases, side effects may be decreased or eliminated by adjusting the dosage of vitamin C.

Interactions

Vitamin C increases iron absorption, and is frequently prescribed with or added to commercial iron supplements for this reason.

Individuals taking anticoagulant, or blood thinning, medications should speak with their doctor before taking vitamin C supplements, as large doses of vitamin C may impact their efficacy.

Large amounts of vitamin C may increase estrogen levels in women taking hormone supplements or birth control medications, especially if both the supplement and the medication are taken simultaneously. Women should speak with their doctor before taking vitamin C if they are taking estrogen-containing medications. Estrogen actually decreases absorption of vitamin C, so larger doses of vitamin C may be necessary. A healthcare provider can recommend proper dosages and the correct administration of medication and supplement.

Individuals who take aspirin, antibiotics, and/or steroids should consult with their healthcare provider about adequate dosages of vitamin C. These medications can increase the need for higher vitamin C doses.

Large dosages of vitamin C can cause a false-positive result in tests for diabetes.

KEY TERMS

Adrenal hormone— The adrenocortical hormones are cortisol and cortisone. They are anti-inflammatory substances that aid in the function of a number of body systems, including the central nervous system, the cardiovascular system, the musculoskeletal system, and the gastrointestinal system.

Antioxidants— Enzymes that bind with free radicals to neutralize their harmful effects.

Bioflavonoids— Plant-derived substances that help to maintain the small blood vessels of the circulatory system.

Free radicals— Reactive molecules created during cell metabolism that can cause tissue and cell damage like that which occurs in aging and with disease processes such as cancer.

In vitro testing— A test performed in a lab setting rather than in a human or animal organism. The test may involve living tissue or cells, but takes place out of the body.

In vivo testing— A test performed on a living organism, such as a controlled clinical study involving human test subjects. In vivo is Latin for "in the living body."

Resources

BOOKS

Reavley, Nocola. The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs. New York: M. Evans & Company, 1998.

PERIODICALS

Henderson, C.W. "Prevalence Lower in Women with Increased Vitamin C Levels." Women's Health Weekly (April 22, 2000): 7.

Leibman, Bonnie. "Antioxidants." Nutrition Action Health Letter (June 2000):9.

"New Questions About the Safety of Vitamin C Pills." Tufts University Health & Nutrition Letter (April 2000): 1.

ORGANIZATIONS

United States Department of Agriculture. Center for Nutrition Policy and Promotion. 1120 20th Street NW, Suite 200, North Lobby, Washington, C.C. 20036. (202) 418-2312. 〈http://www.usda.gov/cnpp/〉. john.webster@usda.gov.