You probably already know a little bit about vitamin C. It’s in oranges, right? (Yes.) And it can help you get over a cold, right? (Kind of.) You’re on the right track, but there’s so much more to vitamin C than that.
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Registered dietitian Devon Peart, RD, MHSc, explains what vitamin C really does for your body and why it’s so important to get enough of it.
What is vitamin C?
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that plays a critical role in your health. “It’s what’s known as an essential nutrient, meaning that your body doesn’t make it,” Peart says, “so you have to get it from your diet.”
And of course, the word “essential” means that your body really needs it. But what for? Well, all kinds of things, including healthy skin, bones, eyes and more.
Vitamin C is a powerful antioxidant, helping to defend your body against cell damage. It also plays an important role in growing and developing tissues, healing wounds and keeping your immune system strong.
Health benefits of vitamin C
What does vitamin C actually do for your body? Peart delves deeper into some of the proven ways that it supports your health, plus a few possibilities that are still being researched.
1. Fights cell damage and disease
Vitamin C is an antioxidant, a natural chemical found in certain foods. You can think of antioxidants like invisible superheroes inside your body. Their main job is to protect you from free radicals, or unstable molecules that can damage your cells, cause oxidative stress, increase signs of aging and more.
“A buildup of free radicals is associated with a risk of diseases like cancer, heart disease and arthritis,” Peart explains. Eating antioxidant-rich foods, like those high in vitamin C, can help protect your body from free radical-related damage.
2. Protects your eyes
Vitamin “see” indeed: This antioxidant is thought to help ward off cataracts (a clouding of the lens of your eye) and slow the progression of age-related macular degeneration (AMD), a condition that causes people to lose their central vision.
“Studies have shown mixed results,” Peart notes, “but we know that vitamin C acts as an antioxidant for cells in the retina and macular region of the eye.”
3. Improves iron absorption
Some plant foods, including beans and spinach, have iron in them (a type called non-heme iron), but they also have properties that make it hard for your body to access that iron. Enter vitamin C, which acts as iron’s wingman.
“Consuming foods that are high in vitamin C in the same meal with iron-rich plant foods boosts the bioavailability of the iron, meaning that you absorb more of it,” Peart explains.
Let’s say you make a spinach salad with strawberries on top. Spinach has non-heme iron, while strawberries are rich in vitamin C. They’re both healthy on their own, but when you eat them together, the vitamin C in the strawberries helps your body access and absorb more iron from the spinach than it could if you just ate the spinach alone.
4. Helps with wound healing
Vitamin C encourages collagen growth, which is an important part of your body’s healing process. “Collagen is a protein that keeps our skin looking young,” Peart adds.
It’s one of the keys to properly healing wounds, including cuts, scrapes and surgical incisions. And people who don’t get enough vitamin C have been shown to heal more slowly than those who get the recommended amount.
5. Promotes healthy skin
We’re mostly talking about the kind of vitamin C that you find in foods, but it’s worth noting that topical creams and serums made with vitamin C can do all kinds of good things for your skin. They help slow signs of aging, reduce dark under-eye circles and even bolster the effects of sunscreen. (Psst: You are wearing sunscreen, aren’t you? Hint, hint.)
Other possible benefits
Science never stops! There are always studies in progress to uncover new health information, including the many roles vitamin C plays in our bodies. Here are a few other possible benefits of vitamin C, though more research is needed on all of them:
- May help you recover quickly: Contrary to what you might’ve heard, vitamin C can’t prevent you from getting sick (sorry). But it can still be of help. “Some studies suggest that it can help lessen the severity and duration of colds and the flu and potentially reduce your risk of further complications,” Peart says.
- May improve heart health: Vitamin C may help prevent and treat cardiovascular disease (CVD), including strokes. Studies so far have been conflicting, though, so researchers still can’t say for certain how effective it might be.
- May play a role in cancer treatments: As researchers continue to learn about cancer, genetics, vitamin C absorption and metabolism, Peart says they’re exploring the role vitamin C might play in treating some types of cancers. “There is some promising evidence so far, as an adjunct to conventional cancer treatment,” she says. This means it could play a role in — but not replace — treatment.
How much vitamin C you need each day
When it comes to vitamin C, a little bit goes a long way — which is to say, it’s not all that difficult to get your recommended daily amount. For example, one medium orange has about 80 milligrams of vitamin C, which accounts for much of your daily intake.
For adults ages 18 and over, here’s how the National Institutes of Health (NIH) breaks down its vitamin C recommendations:
- Men: 90 mg
- Women: 75 mg
- People who are pregnant: 85 mg
- People who are lactating: 120 mg
“Keep in mind that these recommendations are a minimum to prevent deficiency,” Peart says, “and some experts believe the recommendations should be higher.”
These recommendations also don’t take into account bodily differences like weight, height, sex assigned at birth, overall health, etc. Plus, if you smoke, you’ll need about 35 mg more per day because smoking is toxic to cells, causing your body to use up its vitamin C more quickly.
If you’re not sure how much vitamin C you should be getting, talk to a healthcare provider for personalized guidance.
Signs of a vitamin C deficiency
Most people who live in North America get enough vitamin C in their daily diet. But malnourishment, alcohol use disorder, smoking and eating disorders can all lead to low levels of vitamin C.
“Not getting enough vitamin C is fairly uncommon,” Peart states, “but in some cases, people can become deficient in it.” That can lead to scurvy, a more serious form of deficiency that, though rare in North America, is most commonly seen in people who live in extreme poverty and/or those who are under-housed.
Risks of too much vitamin C
If you’re getting vitamin C from the foods you eat, it’s typically not a big deal to get more of it than you need. “The body doesn’t store it,” Peart explains. “In essence, you pee out the excess.”
But too much of a good thing is, well, too much. The upper limit of vitamin C supplements is 2,000 mg per day; at doses higher than that, you may experience side effects like:
- Flushed skin.
- Cramps and/or an upset stomach.
“At very high levels of supplementation, you’re putting an extra burden on your kidneys,” Peart warns. “This can lead to the formation of kidney stones and, in extreme cases, kidney failure.”
Should you take vitamin C supplements?
If you eat a healthy diet, you’re likely already getting enough vitamin C. “You can’t get too much vitamin C from food sources,” Peart says, “so if you eat plenty of vegetables and fruit every day, you will get the recommended amount and more.”
But if you fear you’re not getting enough vitamin C (like if you smoke or if you don’t eat many fruit and veggies), talk to your healthcare provider about whether supplements are safe for you. The usual supplement dosage is 500 mg per day, but they may recommend a different amount.
There are also times when you may want to take extra vitamin C, like if you’re not feeling well.
“If you feel like you’re coming down with a cold or the flu, or if you’re in a period of acute stress and feeling run-down, most people can take up to 1,000 mg vitamin C per day (or temporarily increase your current supplement to that amount),” Peart says. “This helps maintain healthy levels of vitamin C, which get depleted in times of physical stress.”