Vitamin C is one of the best-known nutrients, often associated with oranges and cold season. But its roles in the body go well beyond immunity. Here is what vitamin C does, how much you need and how to get enough.

What vitamin C does

• Supports the immune system: it helps immune cells function normally.
• Builds collagen: vitamin C is essential for making collagen, which supports skin, blood vessels, bones and wound healing.
• Improves iron absorption: eating vitamin C with plant sources of iron, such as beans or lentils, helps your body absorb more iron.
• Acts as an antioxidant: it helps protect cells from damage.

How much do you need?

Health Canada’s Dietary Reference Intakes set the recommended daily amount for adults at:

The tolerable upper intake level for adults is 2,000 mg per day. Very high doses can cause stomach upset and diarrhea.

The best food sources

• Red and yellow bell peppers (one of the richest sources)
• Kiwi fruit and oranges
• Strawberries
• Broccoli and Brussels sprouts
• Tomatoes and potatoes

One medium orange or half a red pepper can provide most of a day’s needs. Vitamin C is sensitive to heat, so raw or lightly cooked vegetables keep more of it.

Does vitamin C prevent colds?

For most people, taking vitamin C regularly does not prevent colds, although some studies suggest it may slightly shorten their duration. People under heavy physical stress, such as marathon runners, may see more benefit. A balanced diet is usually enough.

Who might need more?

• People who smoke
• People with very limited diets
• People with certain medical conditions affecting absorption

Vitamin C in skincare

Topical vitamin C serums are popular for brightening and protecting skin from environmental damage. They work differently from dietary vitamin C. See our guide to ingredients dermatologists recommend.

Supplements: when they make sense

Most Canadians can meet their needs through food. If you consider a supplement, choose a product with a Natural Product Number (NPN) from Health Canada and talk to your doctor or pharmacist, especially if you have kidney problems or take medications.

This article is for general information and is not medical advice.