Everything you need to know about vitamin C

Does it really prevent colds?
By Jessica Leeder
Vitamin C Image, Roberto Caruso

What it does C is arguably the most well-known vitamin — the one many of us have been taught to reach for when a cold is coming on. It plays an important role in the maintenance of cartilage, teeth and bones. The body also uses it to produce collagen and promote tissue growth and repair. “It’s an antioxidant," says Kelly Anne Erdman, a registered dietician in Calgary. "It limits the effects of free radicals — which are produced by our bodies and can have damaging effects at the cellular level." Researchers are also exploring whether vitamin C’s antioxidant properties play a role in preventing cancer, cardiovascular disease, macular degeneration and cataracts. And yet, science has not been able to back up its reputed role in cold prevention.

Are you getting enough? Health Canada’s recommended daily allowance is surprisingly low: infants should have 50 milligrams, while 75 mg are recommended for women aged 19 to 70 and adult males need at least 90 mg. (Lactating women and smokers may require more than the minimum dose.) Considering “an orange could have 70 mg of vitamin C or a glass of juice could have 100 mg,” says Erdman, “this one is easy to get from the food supply.” Other sources include mango, papaya, pineapple, brussels sprouts, broccoli, cantaloupe, cabbage, spinach, cauliflower, strawberries, tomatoes, sweet potatoes and white potatoes.

Before you binge, be aware that vitamin C is water soluble, meaning the body is not able to hold on to reserves. Too much can cause diarrhea, nausea and headaches. Health Canada puts the upper limit for both men and women at 2,000 mg per day. Most people absorb about 500 mg of vitamin C at a time, says Lauren Baker, a registered dietician in Mississauga, Ont. “If you are taking large doses of vitamin C, you might be losing half of what you’re taking. You literally pee it out.” To get the benefits of consuming more, people need to eat a consistent amount of C throughout the day.

When to supplement Most people, says Baker, get enough vitamin C from their diet to avoid taking an off-the-shelf supplement. But those with limited intake of fruits and vegetables or concerns about malabsorption due to chronic diseases (including inflammatory bowel syndrome and kidney disease) should talk to their doctor about a supplement regime.


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