Vitamin C, also known as ascorbic acid, acts as an antioxidant in the body, removing free radicals and stimulating the immune system. The body cannot produce or store vitamin C, so people must consume foods or supplements to get this nutrient into the body. Adult males over 19 should consume at least 90 mg of vitamin C daily and females should have 75 mg or more each day, although the requirements for a given individual may vary. It is difficult to overdose on vitamin C, but Medline Plus recommends not consuming more than 2,000 mg daily since larger amounts may cause diarrhea and nausea.
Orange juice is the most well-known vitamin C powerhouse, but many other juices contain some of this vitamin as well. Apple juice, cranberry juice and white grape juice all contain vitamin C as well. Nonetheless, orange and grapefruit juice remain two of the best juice sources of vitamin C. Orange juice has 10 times the amount of vitamin C as found in apple juice. Some juices are also fortified with vitamin C to add more of this nutrient than would naturally be present or to replace vitamin C lost during processing. Fresh-squeezed juice contains more vitamin C than canned or packaged juices. Juice should be consumed as soon as possible and unused portions should be refrigerated in a sealed container since vitamin C deteriorates upon exposure to air.
One papaya contains 188 mg of vitamin C, 313 percent of the daily value. A single wedge of cantaloupe has 25 mg of vitamin C, over 40 percent of the recommended daily intake for most adults, while half of a grapefruit contains 47 mg. Other fruits high in vitamin C include kiwi, raspberries, strawberries, lemon, cranberries, mango, blueberries and watermelon. Fruit should be eaten soon after cutting or stored in the refrigerator after being cut. The vitamin C content of mango, watermelon and strawberries drops by about 5 percent in the six days after being cut and refrigerated and the vitamin C in cut cantaloupe falls by about 25 percent in the same amount of time.
Many vegetables contain vitamin C, including broccoli, cauliflower, kale, cabbage, Romaine lettuce, Brussels sprouts, Swiss chard, collard greens, spinach, asparagus, snow peas, bell pepper, mustard greens, turnip greens and tomatoes. Raw, red bell pepper is one of the best sources of vitamin C from vegetables, containing 175 mg of vitamin C in a cup of bell pepper slices, 291 percent of the recommended daily intake. Cooking can rapidly lower the vitamin C content of vegetables, so eating these foods raw is a better idea if you're using them to get more of this vital nutrient. According to World's Healthiest Foods, cooking vegetables for 10 to 20 minutes can reduce the vitamin C content by up to 50 percent and even a few minutes of steaming or boiling can cut the vitamin C content by about 25 percent.