Ascorbic Acid in Lemons

Ascorbic acid, or vitamin C, is an essential vitamin, which means that your body needs it but lacks the metabolic machinery to produce it on its own. Ascorbic acid functions in a variety of roles including collagen synthesis and neurotransmitter synthesis; it's also an antioxidant. You can obtain ascorbic acid from many different foods, but citrus fruits are an excellent source. Lemons in particular provide ascorbic acid with relatively few calories.

Lemon Juice

The USDA Nutrient Database shows the juice from one lemon will provide you with about 19 mg of ascorbic acid, or about one quarter of your daily recommended value, and 11 calories. This means that if your sole source of ascorbic acid was derived from lemons, you would need to consume the juice of four to five lemons to meet your recommended intake. Alternatively, the juice of one orange will provide you with 43 mg ascorbic acid and 39 calories.

Flesh of Lemons

Ascorbic acid is not entirely contained in the juice portion of lemons. You also obtain ascorbic acid from the entire lemon. According to the USDA Nutrient Database, a lemon without the peel or seeds contains about 31 mg ascorbic acid and 17 calories. This means that you get an additional 12 mg ascorbic acid by consuming the flesh and juice of a lemon compared with just drinking the juice.

Lemon Peel

The last source of ascorbic acid in lemons comes from the peel. Since you do not generally consume the peel of the lemon with the juice and flesh, this does not account for a lot of dietary ascorbic acid. According to the USDA Nutrient Database, one tablespoon of the peel of a lemon contains 8 mg ascorbic acid and 3 calories. You will commonly consume lemon peel, or lemon zest, in baked goods, such as lemon meringue pie.

Other Sources of Vitamin C

Other sources of ascorbic acid are peaches, strawberries and red sweet peppers. One large peach contains 12 mg ascorbic acid. One cup of whole strawberries contains 85 mg ascorbic acid. One large sweet red pepper contains a whopping 210 mg ascorbic acid and only 51 calories.