Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Humans, unlike most animals, are unable to synthesize vitamin C endogenously, so it is an essential dietary component.
Vitamin C is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters; vitamin C is also involved in protein metabolism. Collagen is an essential component of connective tissue, which plays a vital role in wound healing. Vitamin C is also an important physiological antioxidant.
Vitamin C is one of the safest and most effective nutrients, experts say. A recent study published in Seminars in Preventive and Alternative Medicine that looked at over 100 studies over 10 years revealed a growing list of possible benefits of vitamin C. The benefits of vitamin C may include protection against immune system deficiencies, cardiovascular disease, prenatal health problems, eye disease, and even skin wrinkling. Higher blood levels of vitamin C is also an ideal nutrition marker for overall health.
What is the recommended vitamin C intake?
Intake recommendations for vitamin C and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) of the National Academies (formerly National Academy of Sciences) . DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and gender, include:
- Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
- Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
- Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
- Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
The table below lists the current RDAs for vitamin C . The RDAs for vitamin C are based on its known physiological and antioxidant functions in white blood cells and are much higher than the amount required for protection from deficiency . For infants from birth to 12 months, the FNB established an AI for vitamin C that is equivalent to the mean intake of vitamin C in healthy, breastfed infants.
Recommended Dietary Allowances (RDAs) for Vitamin C
|0–6 months||40 mg*||40 mg*|
|7–12 months||50 mg*||50 mg*|
|1–3 years||15 mg||15 mg|
|4–8 years||25 mg||25 mg|
|9–13 years||45 mg||45 mg|
|14–18 years||75 mg||65 mg||80 mg||115 mg|
|19+ years||90 mg||75 mg||85 mg||120 mg|
|Smokers||Individuals who smoke require 35 mg/day|
more vitamin C than nonsmokers.
* Adequate Intake (AI)
How much vitamin C is too much?
The tolerable upper intake level (or the maximum amount you can take in a day that likely won’t cause harm) is 2000 mg a day for adults.
Can you overdose on vitamin C?
Yes, you can overdose on vitamin C, high doses usually more than say, 2,000 or 3,000 mg per day can cause symptoms such as diarrhea, nausea, heartburn, gastritis, fatigue, flushing, headache, and insomnia. Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Sticking with the recommended dose of vitamin C will not only prevent unwanted side effects, it will also ensure that your body benefits maximally from the very many benefits of this super medication.
Vitamin C side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using vitamin C and call your doctor at once if you have:
- joint pain, weakness or tired feeling, weight loss, stomach pain;
- chills, fever, increased urge to urinate, painful or difficult urination; or
- severe pain in your side or lower back, blood in your urine.
Common side effects may include:
- heartburn, upset stomach; or
- nausea, diarrhea, stomach cramps.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.