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Vitamin C – Better from Food or Supplements?


Because vitamin C is necessary for a healthy immune system, some begin taking supplements to prevent the risk of getting a cold or to shorten the duration of symptoms. But would eating food be a better option instead of popping pills? A new study from the University of Otago studied the bioavailability of vitamin C in foods versus dietary supplements.

Vitamin C is a water-soluble vitamin that is necessary for normal growth and development. It also acts as an antioxidant, blocking damage that is caused by free radicals (which play a role in cancer, heart disease and conditions like arthritis.)

For many years, vitamin C has been a popular remedy for the common cold. However, research shows that for most people, the vitamin does not reduce the risk of colds, though it may help slightly reduce the length of a cold or may lead to somewhat milder symptoms.

Foods rich in vitamin C include cantaloupe, citrus fruits and juices (orange, grapefruit), kiwi fruit, mango, papaya, pineapple, berries (strawberries, raspberries, blueberries, cranberries), watermelon, broccoli, Brussels sprouts, cauliflower, green and red bell peppers, leafy greens, sweet and white potatoes, tomatoes, and winter squash.

Vitamin C was first chemically synthesized in the early 1930s as a way to introduce the necessary vitamin to those without access to vitamin c-rich foods.

Anitra C. Carr and Margreet CM Vissers of the Center for Free Radical Research at the University of Otago (New Zealand) compiled data from both human and animal studies to find if the synthetic version of vitamin C is just as bioavailable to the body as natural vitamin C found in food.

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The team determined that synthetic and food-derived vitamin C is chemically identical. However, fruits and vegetables provide a number of other micronutrients, dietary fiber, and phytochemicals that are not a part of vitamin C supplements.

For example, some fruit (kiwi is an example) also contain vitamin E. This vitamin is known to help preserve vitamin C in vivo. Plant-derived flavonoids may also help the body “spare” vitamin c and therefore increase its bioavailablilty.

There is of course a benefit to taking vitamin C in a pill versus food. Supplemental vitamin C typically takes about two hours to reach maximal plasma levels following ingestion. Some animal studies indicate that vitamin C from food takes much longer to provide the same benefit. However, this effect is most beneficial to those suffering a deficiency in vitamin C (ie Scurvy) or for those who need additional vitamin C above the RDI due to a condition such as wound healing.

Doses of vitamin C up to 200 mg/day are considered safe for general consumption. However, if you do choose to go the dietary supplement route for your vitamin C needs, keep in mind that single doses of vitamin C greater than 200 mg have a lower relative bioavailability, indicating it is much preferable to get the vitamin over several small doses rather than a single large dose.

Overall, the researchers find that getting vitamin C from food is preferable over supplements for most individuals. Food-derived vitamin C (ie fruits and vegetables) is associated with decreased incidence of stroke, coronary heart disease, and cancers at various sites.

Carr AC, Vissers MCM. Synthetic or Food-Derived Vitamin C – Are They Equally Bioavailable? Nutrients 2013, 5, 4284-4304;doi:10.3390/nu5114284

Additional Resources:
National Institutes of Health: Vitamin C