We get it: You want to protect your body from disease, and chugging a ton of orange juice or Emergen-C seems like a tasty and easy way to do it. But can you consume too much vitamin C? The short answer is “yes.”
Here’s what you need to know:
What Is Vitamin C and Where Is It Found?
Citrus Getty 2/26/20
Credit: twomeows/Getty Images
twomeows/Getty Images
Vitamin C, also known as ascorbic acid, is an essential nutrient.
Common food sources of vitamin C are citrus fruits, broccoli, kale, sweet potatoes, tomatoes, kiwifruit, cantaloupe, papaya, and peppers.
It’s also often sold as a dietary supplement in pill or tablet forms. Some vitamin C supplements are marketed as immune system-supporting, like Emergen-C and Airborne.
Vitamin C Benefits
When consumed in appropriate amounts, vitamin C:
- Supports a healthy immune system. Vitamin C is known as an immune-boosting superstar because it encourages white blood cell production and helps these blood cells function more effectively by protecting them against harmful molecules. So why is this so important? White blood cells are essential in protecting your body against infection.
- Helps prevent iron deficiency. Vitamin C can help your body more effectively absorb iron, which is essential for transporting oxygen throughout the body. This benefit is especially important for people who don’t eat meat or who are prone to anemia.
- Can reduce your risk of heart disease. Heart disease, the leading cause of death in the U.S., is often caused by high blood pressure and/or high cholesterol. Studies have shown that adequate vitamin C consumption may be helpful in reducing those risk factors, thereby reducing your risk of heart disease.
How Much Vitamin C Do You Need?
Emergen-C Getty 3/13/20
Credit: Chelsea Lauren/Getty Images
Chelsea Lauren/Getty Images
Most adults should consume 65 to 90 milligrams (mg) of vitamin C per day, according to the Mayo Clinic. You can meet this daily quota with about two oranges. The Office of Dietary Supplements says the upper limit for vitamin C intake is about 2,000 mg for men and women over 19 years old. It would be hard to reach this amount with food alone, but you may accidentally take too much if you rely on supplements for your vitamin C needs—especially chewables or effervescent tablets that taste good.
Too Much Vitamin C Side Effects
Digestive Upset Getty 3/17/20
Credit: Varangkana Petchson / EyeEm/Getty Images
Varangkana Petchson / EyeEm/Getty Images
While taking megadoses of vitamin C is unlikely to be harmful in the long run, it can cause some pretty unpleasant side effects. Common side effects of too much vitamin C include:
- Diarrhea
- Nausea
- Vomiting
- Bloating
- Heartburn
- Headache
- Insomnia
While these issues are generally more uncomfortable than harmful, more severe side effects can occur. For instance, taking too much vitamin C can cause your body to produce too much iron. This can lead to serious damage to your heart, central nervous system, and liver. This damage is unlikely unless you have a condition that affects iron absorption, however.
Overconsumption of vitamin C can also cause kidney stones. Excess vitamin C is excreted via urine as a waste product known as oxalate, which can bind to minerals and form stones.
- If you take more than 2,000mg of vitamin C, it can lead to negative side effects like abdominal pain, nausea, and headaches.
- Doctors say it's nearly impossible to get too much vitamin C from food sources, though you should be more careful with vitamin C supplements.
- The daily recommended amount of vitamin C you should ingest is 65 to 90 mg — however, this may vary depending on your lifestyle and pre-existing conditions, so it's best to ask your doctor first.
Vitamin C (ascorbic acid) is an essential nutrient your body needs to heal and grow, however, you can take too much of it.
Generally, you can't take too much vitamin C by eating food that is high in it, such as in citrus fruits like oranges. However, taking too many vitamin C supplements can result in significant side effects such as an upset stomach.
Because your body doesn't produce vitamin C naturally, it's important to include it in your diet. For the average adult, the daily recommended amount of vitamin C is 65 to 90 milligrams (mg) per day.
However, this dose may be different during pregnancy or while breastfeeding, so make sure to consult your doctor before making any changes to your diet.
Here are the benefits of vitamin C, how much vitamin C is too much, and who's at risk for serious complications due to an excess of vitamin C.
How does vitamin C affect the body?
Vitamin C is a powerhouse nutrient the body shouldn't go without. It has the ability to repair tissue, stimulate the production of white blood cells, and reduce inflammation and other physical effects of stress. Vitamin C can also lower your risk of stroke and help with iron absorption.
"Vitamin C is a critical antioxidant that is involved in the structure and function of nearly every part of the body," says Beverly Goode-Kanawati, DO, and director and founder of Beverly Medical Center in Raleigh, NC. "For example, vitamin C is needed to create collagen which is the underpinning of structures for everything from the skin to bones."
Since the body doesn't create vitamin C on its own, you need to get it in your diet or in supplemental form vitamin C is found in a variety of foods, including:
- Citrus fruits
- Strawberries
- Brussel sprouts
- Potatoes
- Broccoli
- Peppers
What happens if you take too much vitamin C?
Though vitamin c is an essential nutrient for your body, you can ingest too much of it. Although you cannot technically "overdose" on vitamin C, taking more than the maximum recommended amount of 2,000mg of vitamin C per day may cause uncomfortable side effects, including:
- Diarrhea
- Abdominal pain
- Heartburn (or acid reflux)
- Hemolysis (G6PD deficiency is present)
- Nausea (or vomiting)
- Headaches
- Rebound scurvy (in infants born to women taking high doses of vitamin C)
- Sleeping problems (insomnia)
- Skin irritation and the formation of blackheads
Because vitamin C is a water-soluble vitamin, you're less likely to experience vitamin toxicity than you would with potassium, for example. This is because water-soluble vitamins dissolve in water and are absorbed in the small intestine. In other words, your body uses what it needs from the vitamin and discards the rest through your urine.
"Vitamin C is a water-soluble vitamin and if you take large doses of it, your body will safely excrete it through the urine," says Dimitar Marinov, MD, Assistant Professor at the Department of Hygiene and Epidemiology, Medical University of Varna, Bulgaria. "However, taking large doses for long periods can lead to health problems such as hyperoxaluria and kidney stones. If you have a history of kidney stones, avoid vitamin C supplementation."
Both Marinov and Goode-Kanawati claim negative side effects only occur when you take too much vitamin C in supplemental form and that it's nearly impossible to consume an excessive dosage of vitamin C in food form.
"The reason is that many supplements contain four to 20 times higher doses than the recommended daily intake," Marinov says.
How much vitamin C should you take?
So, what's the right amount of vitamin C to take? The right dosage can vary depending on your age, gender, and lifestyle. Listed below are the daily recommended amounts of vitamin C according to the National Institutes of Health:
Ingesting large doses of a vitamin C supplement or a cold-fighting product like Emergen-C, however, may cause more serious effects. "The same effects from excess vitamin C ingestion can occur with Emergen-C but because this formula also contains large amounts of potassium, side effects can also include more serious symptoms and signs such as weakness, low blood pressure, and heart arrhythmias," says Rand McClain, DO, and chief medical officer of Live Cell Research.
What are some long-term effects of taking too much vitamin C?
Vitamin C is water-soluble, so it's difficult to keep it in your system.
According to the National Institutes of Health, consuming vitamin C in large doses overtime could cause a reduced amount of vitamin B12 and copper, an accelerated metabolism, allergic responses, and the erosion of dental enamel. In addition, Vitamin C may negatively interact with other medications, including, but not limited to, chemotherapy drugs and cholesterol-reducing medications (statins).
For people with hemochromatosis, for example, too much vitamin C could be harmful and even life-threatening. Hemochromatosis is a condition in which the body produces too much iron, which can be toxic and cause damage to the heart, liver, and pancreas.
"Vitamin C is not likely to cause hemochromatosis in healthy people, but those who have a higher risk of iron build up should avoid supplementation," says Marinov.
Insider's takeaway
Vitamin C has several important functions, including maintaining healthy blood vessels, bones, and cartilage. Even so, taking too much vitamin C may cause digestive problems or more serious side effects for those with preexisting conditions such as kidney disease or hemochromatosis.
"Unless your diet is completely deprived of fresh plant foods vitamin C supplementation is typically not necessary," says Marinov.
Related articles from Health Reference:
- 5 science-backed benefits of vitamin B12 and how to get enough of it
- What is vitamin E good for?
- The best vitamins to help your hair's growth, thickness, and overall health.
- 5 science-proven benefits of vitamin A
- 6 healthy foods rich in vitamin D
Tabitha Britt is a New York-based freelance writer and editor. When she's not glued to her computer screen, she can be found walking her beloved pooch, Biscuit. Aside from writing for INSIDER, Tabitha is also the founding editor-in-chief of DO YOU ENDO — the first no-BS endometriosis magazine (by individuals with endometriosis, for individuals with endometriosis) in America. She earned her Master's degree in Creative Publishing and Critical Journalism from The New School of Social Research.
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