Citrus fruits (lime, lemon, orange, grapefruit), tomatoes, and potatoes are good common sources of vitamin C. Other foods that are good sources of vitamin C include papaya, broccoli, brussels sprouts, black currants, strawberries, cauliflower, spinach, cantaloupe, and kiwifruit. Also, cranberries and red peppers are good sources of the vitamin.

The amount of vitamin C in foods of plant origin depends on:

• the precise variety of the plant,
• the soil condition
• the climate in which it grew,
• the length of time since it was picked,
• the storage conditions,
• the method of preparation. Cooking in particular is often said to destroy vitamin C – but see the section on Food preparation.

Vitamin C or L-ascorbate is an essential nutrient required to allow a range of essential metabolic reactions in animals and plants, and widely known as the vitamin that prevents scurvy in humans. The pharmacophore of vitamin C is the ascorbate ion. In living organisms, ascorbate is an antioxidant, as it protects the body against oxidative stress, and a cofactor in several vital enzymatic reactions. As a nutrient, its uses and requirements are matters of on-going debate. The North American Dietary Reference Intake recommends 90 milligrams per day and no more than 2 grams per day (2000 milligrams per day). As a food additive, vitamin C is used as an antioxidant preservative and an acidity regulator. Several E numbers account for the vitamin, depending on its chemical structure: E300 as ascorbic acid, E301 as sodium ascorbate, E302 as calcium ascorbate, and E303 as potassium ascorbate.