There are several fruits and vegetables with high vitamin C content including strawberries, orange, grapefruit, sweet red pepper, and broccoli.

Natural and synthetic L-ascorbic acid are chemically identical and there are no known differences in their biological activities or bioavailability (44).

In supplements, vitamin C (L-ascorbic acid) is available in many forms but there is little scientific evidence that any one form is better absorbed or more effective than another.

Mineral salts of ascorbic acid, such as sodium ascorbate and calcium ascorbate, are buffered and therefore less acidic than ascorbic acid. Some people find them less irritating to the gastrointestinal tract than ascorbic acid.

Sodium ascorbate generally provides 131 mg sodium per 1,000 mg ascorbic acid and pure calcium ascorbate provides 114 mg calcium per 1,000 mg ascorbic acid.

Bioflavonoids are a class of water-soluble plant pigments that are often found in vitamin C-rich fruits and vegetables, especially citrus fruits. Although many bioflavonoids are thought to function as antioxidants, there is little evidence that the bioflavonoids in most commercial preparations increase the bioavailability or efficacy of vitamin C (45).