Vitamin C, also known as ascorbic acid, is a water-soluble compound that serves as an indispensable nutrient for human health. The human body cannot produce vitamin C on its own, so it must be obtained through diet or supplements. This nutrient is involved in various biological processes, supporting overall well-being and cellular health.
Natural Sources of Vitamin C
Fruits and vegetables are excellent natural sources of vitamin C. Citrus fruits like oranges, grapefruits, and lemons are well-known for their vitamin C content, with a medium orange offering about 70 milligrams. Strawberries and kiwi fruit also contain substantial amounts, with a single kiwi delivering approximately 132 milligrams.
Many vegetables are also rich in this nutrient. Bell peppers, particularly red and yellow varieties, are notable sources, with a cup of chopped red peppers containing around 190 milligrams. Broccoli and Brussels sprouts are other vegetables that provide significant vitamin C, with a cup of chopped broccoli offering about 81 milligrams. Including a variety of these foods in your diet helps ensure adequate vitamin C intake.
Key Roles of Vitamin C in the Body
Vitamin C performs several key functions within the human body. It is a cofactor in collagen biosynthesis, a protein that provides structural integrity to skin, bones, cartilage, tendons, ligaments, and blood vessels. This role is important for tissue repair and wound healing, as vitamin C helps convert amino acids into stable collagen fibers.
The nutrient also acts as a strong antioxidant, protecting cells from damage caused by unstable molecules called free radicals. This antioxidant activity helps mitigate oxidative stress, which is linked to various chronic health conditions. Vitamin C also contributes to immune system function by supporting the production and effectiveness of white blood cells, which defend the body against infections.
Natural Versus Synthetic Vitamin C
A common question is whether natural vitamin C from foods is superior to synthetic versions, typically ascorbic acid. Chemically, natural L-ascorbic acid found in foods and synthetic L-ascorbic acid are identical. Their molecular structure and biological activity are the same.
Research comparing the bioavailability of natural and synthetic vitamin C in humans shows no significant differences in how the body absorbs and utilizes them. Studies have found that ascorbic acid from sources like orange juice, cooked broccoli, orange slices, or synthetic tablets are equally bioavailable. While some natural sources contain compounds like bioflavonoids, research indicates these do not significantly enhance or impair ascorbic acid’s bioavailability.
Optimal Intake and Considerations
For most adults, the recommended daily intake of vitamin C ranges from 75 mg for women to 90 mg for men. These amounts can typically be met through a balanced diet rich in fruits and vegetables. The body does not store vitamin C in large quantities because it is water-soluble, meaning any excess is excreted in urine.
Cooking methods can affect the vitamin C content in foods. Since ascorbic acid is water-soluble and sensitive to heat, prolonged cooking times or high temperatures can reduce its nutritional benefits. Steaming or microwaving may help preserve more of the vitamin C content compared to boiling. Consuming fruits and vegetables raw whenever possible is an effective way to maximize vitamin C intake. While generally safe, extremely high doses of vitamin C from supplements, exceeding 2,000 mg daily, may lead to gastrointestinal discomfort like stomach pain or diarrhea.