Can Vitamin C Help You Fight a Cold?

Not only can it strengthen your immune system, but vitamin C can do a whole lot more, too

The immune-boosting powers of vitamin C border on being legendary. But if that’s the only health benefit that you associate with vitamin C … well, you’re definitely shortchanging the nutrient.

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The “do-good” list attached to vitamin C is lengthy — particularly when it comes to the health and development of children. And it may help you avoid taking a sick day.

Let’s take a closer look with pediatric immunologist John McDonnell, MD.

How vitamin C helps you

Let’s start with vitamin C’s big claim to fame as a warrior against sickness. “As an immunologist, I love vitamin C because it’s very important for the proper functioning of your immune system,” says Dr. McDonnell.

Vitamin C is an antioxidant that works to reduce damage to cells caused by free radicals roaming around your body. That’s why vitamin C — also known as ascorbic acid — is touted as a way to limit cold and flu symptoms. (More on that in a bit.)

“It helps your immune cells get to the site of an infection and then helps those immune cells eliminate whatever’s infecting your body,” explains Dr. McDonnell.

But vitamin C also is important so your body can form:

  • Collagen, blood vessels, cartilage and muscle. This helps to maintain many body tissues, including your skin. It also aids with connective tissue repair and wound healing according to one study
  • Neurotransmitters, the chemicals that are important for signaling in the nervous system.
  • Carnitine, a chemical that supports the transport and breakdown of fatty acids to generate energy.
  • Healthy bones and teeth, which are super important during your child’s formative years.

Can vitamin C actually prevent a cold?

There’s been a lot of debate regarding whether vitamin C can help prevent the common cold.

“Some research suggests that vitamin C does help decrease the severity of a cold, while other research contradicts that,” says Dr. McDonnell. “The truth probably falls somewhere in between.”

Bottom line? Sipping a glass of orange juice or eating a handful of berries won’t hurt if you start feeling a cold coming on. An illness-fighting vitamin C supplement might be worth trying, too.

“Just don’t expect too much,” cautions Dr. McDonnell.

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How much vitamin C do you need?

It’s pretty clear vitamin C is important. The next question, of course, is how much do you need? The U.S. Department of Health and Human Services offers these daily recommendations, by age.

  • 0–6 months: 40 mg.
  • 7–12 months: 50 mg.
  • 1–3 years: 15 mg.
  • 4–8 years: 25 mg.
  • 9–13 years: 45 mg.
  • 14–18 years: 65 to 75 mg.
  • 19+ years: 75 to 90 mg.

The good news? Most people who eat a healthy diet consume enough vitamin C without having to really focus on it.

But global studies indicate there are regions where vitamin C deficiencies are common given limited access to food. Certain health conditions — including autism — also can lead to a vitamin C deficiency.

In addition, smoking reduces the amount of vitamin C your body absorbs from food, which can lead to deficiencies.

The best sources of vitamin C

Your body can’t produce vitamin C on its own. But luckily, getting enough of the nutrient is as simple as eating a healthy diet featuring a variety of colorful fruits and vegetables, says Dr. McDonnell.

Vitamin C is commonly found in foods such as:

  • Citrus fruits, with oranges holding a starring role.
  • Apples.
  • Berries.
  • Broccoli.
  • Peppers.
  • Potatoes.
  • Tomatoes.

Vitamin supplements also can add some vitamin C to your system, says Dr. McDonnell. It’s always best to talk to a healthcare provider before beginning a dietary supplement.

Signs of vitamin C deficiency

The main condition caused by a vitamin C deficiency is scurvy, which can be fatal.

The disease was once the scourge of the seas. Scurvy sickened and killed millions of sailors between the 16th and 18th centuries, given long voyages that restricted access to fresh fruits and vegetables.

Symptoms of scurvy include:

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  • Anemia.
  • Swollen, bleeding gums that may become purple and spongy.
  • Loosened teeth that may fall out.
  • Bleeding under your skin (skin hemorrhages) that appear as a rash of brown, red or blue spots.
  • Rough, scaly skin that easily bruises.
  • Dry, brittle hair that coils like a corkscrew.
  • Weakness and discomfort.

Diagnosing scurvy requires blood tests to find your vitamin C levels.

Can you get too much vitamin C?

As fabulous as vitamin C may be, it’s possible to get too much of a good thing.

There’s a whole host of issues that can come from overdoing it and taking too much vitamin C, notes Dr. McDonnell. (FYI: Your body gets rid of excess vitamin C through your kidneys.)

Symptoms of too much vitamin C could include:

This isn’t something you’re going to experience eating an extra orange at lunch, though. But it could become an issue if you’re taking in extremely high levels of vitamin C through dietary supplements.

The bottom line on vitamin C

Vitamin C is essential to your body functioning at its best. Odds are you get enough vitamin C through your diet. A supplement may help if you feel a cold coming on … but don’t expect any miracles.

“There’s not a huge benefit of taking more vitamin C than what’s recommended,” says Dr. McDonnell. “Your body just needs what it needs — nothing more and nothing less.”

To hear more from Dr. McDonnell on this topic, listen to the Health Essentials Podcast episode “The Power of Vitamin C.” New episodes of the Health Essentials Podcast are available every Wednesday.

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