Vitamin C
Natural Standard evidence-based flashcard. Copyright © 2008 (www.naturalstandard.com). Commercial distribution prohibited. This flashcard is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions. 		Image
While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.

Summary:
Vitamin C (ascorbic acid) is a vitamin that the body needs to form collagen in bones, cartilage, muscle, and blood vessels. It also helps the body absorb iron. Vitamin C is found in foods like fruits and vegetables (especially citrus fruits like oranges).

Uses
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Grade*
Vitamin C deficiency, scurvy A
Common cold prevention (extreme environments) B
Iron absorption enhancement B
Urinary tract infection (during pregnancy) B
Asthma C
Bleeding stomach ulcers caused by aspirin C
Cancer prevention C
Cancer treatment C
Complex regional pain syndrome C
Helicobacter pylori infection C
Ischemic heart disease C
Metabolic abnormalities (alkaptonuria) C
Plaque/calculus on teeth C
Pneumonia (prevention) C
Pregnancy C
Prostate cancer C
Skin damage caused by the sun (UVA-induced) C
Skin pigmentation disorders (perifollicular pigmentation) C
Stroke prevention C
Vaginitis (redness or swelling of the vagina) C
Cataracts (prevention/progression) D
Common cold prevention (general) D
Common cold treatment D
Heart disease prevention D
Premature infants D
*Key to grades: A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).

Safety:
Avoid if allergic or sensitive to vitamin C product ingredients. Vitamin C is generally considered safe in amounts found in foods. Vitamin C supplements are also generally considered safe in most individuals if taken in recommended doses. Avoid high doses of vitamin C with glucose 6-phosphate dehydrogenase deficiency, kidney disorders or stones, cirrhosis (inflammation of the liver), gout, or paroxysmal nocturnal hemoglobinuria (bleeding disorder). Vitamin C intake from food is generally considered safe if pregnant or breastfeeding. It is not clear if vitamin C supplements in doses higher than Dietary Reference Intake recommendations are safe for pregnant or breastfeeding women. Vitamin C is naturally found in breast milk.

Possible side effects:
Abdominal cramps, dental erosion, dizziness, faintness, fatigue, flushing, gastritis, headache, heartburn, hemolysis (red blood cell destruction), injection site discomfort, kidney stones, nausea, renal insufficiency (kidney function problems), scurvy, severe diarrhea, vomiting.

Possible interactions:
Acetaminophen, aluminum-containing antacids such as aluminum hydroxide (Maalox®, Gaviscon®), aspirin, barbiturates including phenobarbital (Luminal®, Donnatal®), pentobarbital (Nembutal®), or secobarbital (Seconal®), blood thinners (warfarin), drugs that may damage the kidneys, ethinyl estradiol, fluphenazine, levodopa therapy, nicotine products such as cigarettes, cigars, chewing tobacco, or nicotine patches, oral estrogens (birth control pills), tetracycline antibiotics such as doxycycline (Vibramycin®), minocycline (Minocin®), or tetracycline (Sumycin®), and herbs and supplements with similar effects.

Dosing:

Adults (18 years and older):
Dietary Reference Intakes (DRIs): Recommended daily intake by the U.S. Food and Nutrition Board of the Institute of Medicine for men older than 18 years old is 90 milligrams per day; for women older than 18 years old is 75 milligrams per day; for pregnant women older than 18 years old is 85 milligrams per day; for breastfeeding women older than 18 years old is 120 milligrams per day.

Children (younger than 18 years):
Adequate Intakes (AIs) and U.S. Dietary Reference Intakes (DRIs): Adequate Intakes (AIs) and U.S. Dietary Reference Intakes (DRIs) for infants ages 0-6 months old is 40 milligrams per day, and for infants 7-12 months old is 50 milligrams per day. The DRI for children 1-3 years old is 15 milligrams per day; for 4-8 years old is 25 milligrams per day; for 9-13 years old is 45 milligrams per day; for 14-18 year old males is 75 milligrams per day; for 14-18 year-old females is 65 milligrams per day; for 14-18 year-old pregnant females is 80 milligrams per day; for 14-18 year-old breastfeeding females is 115 milligrams per day.
Other dosing recommendations vary based on the cause. Please check with a doctor and pharmacist.
Natural Standard Monograph (www.naturalstandard.com)
Copyright © 2008 Natural Standard Inc. Commercial distribution or reproduction prohibited.
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.