Side Effects of Too Much Vitamin C and Dosage

Vitamin C: It's essential.

Too much vitamin C proves it's indeed possible to get too much of a good thing. While toxicity is rare, an excess of the vitamin could lead to side effects such as indigestion and iron overload. To avoid such problems, it's best to monitor your vitamin C intake, especially if you have a pre-existing health condition.

Essential Vitamin C

Vitamin C (ascorbic acid) is a water-soluble essential vitamin needed for normal growth and development. Since the body is unable to produce the nutrient on its own, it must be part of a daily diet. All fruits and vegetables contain vitamin C, with citrus fruits being the best known of the lot. However, there are many other excellent sources, including broccoli and red peppers.

Antioxidant Benefits

Vitamin C's antioxidant properties are said to defend the body from colds and infection as well as accelerate healing. To see vitamin C in action, consider an apple that's been peeled. Once exposed to the air, the apple begins to turn brown due to the oxidation process. However, squeeze some lemon juice over the apple and the browning slows. The antioxidant effect of vitamin C slows the oxidation process.

Your body uses vitamin C in a similar way to counteract free radicals. The vitamin's presence has been linked to the prevention of ulcers and even cancer. By fortifying the immune system, vitamin C helps strengthen the body against deterioration.

You can help your body in its quest for optimum health by maintaining the recommended daily allowance (RDA) for vitamin C. According to the National Academy of Sciences, the numbers are:

  • Men 19 and older: 90 milligrams/day
  • Women 19 and older: 75 mg/day
  • Pregnant women: 85 mg/day
  • Women who are breastfeeding: 120 mg/day
  • People who smoke: 100 mg/day (at least)
  • Children up to 13 years of age: 15-45 mg/day
  • Adolescents, 14-18 years: 65-75 mg/day

Yet too much of the vitamin could have adverse effects as well, although this generally depends on a person's individual health history. What are the risks of too much ascorbic acid?

Effects of Too Much Vitamin C

While it is rare for the body to overdose, side effects from megadoses of vitamin C are possible. For instance, vitamin C aids in the absorption of iron in the body. However, for people with hemochromatosis (an inherited condition of iron overload), supplemental vitamin C is not recommended as it can further complicate the condition.

Independent researchers who study the effects of vitamin C have divergent opinions on what is the proper daily intake. Promoting the nutrient's therapeutic effects, some groups recommend intakes far higher than the RDA. For instance, the Vitamin C Foundation recommends people get 3,000 mg/day. The Linus Pauling Institute sets the bar at 400 mg/day. Conflicting information such as this often confuses people as to what is too much.

Side Effects for Health

For most people, it's difficult to get too much vitamin C. The tolerable upper limit is 2,000 mg/day. Also, being water-soluble, the vitamin isn't stored in the body; any excess is usually flushed out through urine. However, some people may experience the following side effects:

  • Nausea
  • Diarrhea
  • Gastritis
  • Fatigue
  • Cramps
  • Kidney stones

As with hemochromatosis, research suggests some health conditions could be complicated by megadoses of vitamin C. Precautions for patients with gout, sickle-cell anemia, and cirrhosis should be taken.


Vitamin C is used in the treatment and prevention of scurvy. Other conditions where vitamin C may be considered include anemia, high cholesterol, and gingivitis.

Vitamin C Supplements

Vitamin C supplements are commonly available in doses of 500 mg and 1,000 mg. Given the nutrient's association with cold prevention, many people have chosen to supplement their diets with vitamin C pills.


However, it should be noted that the RDA for most adults can easily be met through consumption of whole foods like broccoli, Brussels sprouts, strawberries, and citrus fruit. The possible adverse effects of megadoses should also be factored into the equation.

For your consideration, the following foods equal 100 milligrams or more of vitamin C:

  • Broccoli (1 1/2 cup)
  • Cantaloupes (1/2 medium)
  • Currants (90g)
  • Guavas, canned (100g)
  • Grapefruit juice (1 cup)
  • Honeydew melon (1/2 medium)
  • Kiwifruit (2 medium)
  • Mandarin orange sections (2 cups)
  • Mangoes (2 medium)
  • Orange, navel (1 1/2 medium)
  • Red peppers (raw, 1 pod)
  • Strawberries (1 1/2 cup)
Trending on LoveToKnow
Side Effects of Too Much Vitamin C and Dosage