Vitamin C is essential to good health, boosting the immune system, and supporting our overall wellbeing.

A sneeze, a cough, or a scratchy throat might send you running to the drugstore for extra vitamin C. But do we really need extra vitamin C to keep a cold at bay? Is there such a thing as too much vitamin C?

In our “How Much is Too Much?” mini-series, we’ll explore the nutrients that we most often lack—and the ones we run the risk of taking too much and overcompensating.

Why is vitamin C important?

Vitamin C (ascorbic acid) is a nutrient that plays a variety of vital functions. Vitamin C is perhaps most famous for its ability to boost our immune systems. We need vitamin C to help with tissue growth, development, and repair, and to help form blood vessels, cartilage, muscle and collagen.

Vitamin C is also an antioxidant vital to the healing process and helps protect cells from free radicals, the unstable molecules that play a role in heart disease, cancer, and other diseases. Vitamin C also boosts the body’s ability to absorb and store iron, another essential nutrient for good health.

What’s the recommended amount of vitamin C?

The recommended vitamin C dosage per day for healthy women is 75 mg per day and for men it’s 90 mg per day.

Our bodies cannot produce vitamin C without proper nutrition or supplements, so make sure you include these vitamin C–rich foods in your diet:

• citrus fruits
• berries
• broccoli
• cabbage
• peppers
• potatoes
• tomatoes

Should we take extra vitamin C?

You probably do not need to spend extra money on vitamin C tablets or powders. According to the Mayo Clinic, most people get enough vitamin C from a healthy diet that includes fruits and vegetables. Vitamin C deficiency is more likely in people who:

• smoke or are exposed to secondhand smoking
• have certain gastrointestinal conditions or certain types of cancer
• have a limited diet that doesn’t regularly include fruits and vegetables

Even if I am sick?

Taking oral vitamin C supplements won’t prevent the common cold. Evidence shows minimal benefits to taking vitamin C supplements to shorten your cold or reduce cold symptoms.

But check with your doctor about your specific health concerns. Studies have shown that taking oral vitamin C supplements in combination with other vitamins and minerals seems to prevent age-related macular degeneration from worsening. Other research shows that people who have higher levels of vitamin C in their diets may have a lower risk of developing cataracts.

Can we have too much vitamin C?

You are probably not at risk of overdoing vitamin C, especially if you are eating a balanced diet and following your doctor’s directions on vitamin C supplements. But if you have been taking more vitamin C than usual, you could notice some stomach upset—nausea, vomiting, cramps, diarrhea—headaches or skin flushing. And in some people, high doses of oral vitamin C supplements can cause kidney stones.

Finally, tell your doctor if you’re taking vitamin C supplements before having any medical tests. High levels of vitamin C might interfere with the results of certain tests, such as stool tests for occult blood or glucose screening tests.

More to come…

Stay tuned for additional entries to our “How Much is Too Much?” mini-series!