Vitamin C, also called ascorbic acid, is a readily available nutrient that humans should consume daily. Fresh fruits and vegetables are the best sources of natural vitamin C, though small amounts can also be found in some fish and dairy products. Though vitamin C is available in pill form, the nutrient is more easily absorbed through natural sources.
Doctors recommend consuming 40-125 milligrams of ascorbic acid each day. When natural vitamin C is obtained from whole foods, there is almost no risk of toxicity through over-consumption. The human body cannot store ascorbic acid, and supplies must be replenished daily.
Many fruits and vegetables provide an entire day’s worth of natural vitamin C in a single serving. Oranges and other citrus fruits are readily available throughout most of the world and are considered to be excellent sources of vitamin C. An average orange contains about 70 milligrams of the vitamin, and an average grapefruit contains 170 milligrams. There are a number of fruits that contain even higher levels, such as the kiwifruit, with 180 milligrams, and the tiny kakadu plum, which grows to only a half-inch (1.3 cm) long but contains 60 milligrams of vitamin C per fruit. A handful of kakadu could easily provide 600 milligrams or more of ascorbic acid.
Some of the best sources of vitamin C are difficult to cultivate and thus can be found only in their natural environment. Such fruits include acerola, camu camu and baobab. In their native habitats, these fruits are collected and eaten when they are available. Some tropical fruits, such as the papaya, guava and persimmon, are easily farmed and are available at markets in regions in which they normally would not grow. These three fruits are excellent sources of ascorbic acid, each one containing more than 150 milligrams per fruit.
Natural vitamin C can also be obtained through extracts from many plants. Jujubes, which contain about 130 milligrams per ounce (30 g), might be difficult to find in most parts of the world, but their extract is readily available. Rose hips — the dry, sugarless fruit of the rose bush — are another excellent source of vitamin C and can be dried and made into a tea.
Fruits are not the only foods that contain natural vitamin C. Brussels sprouts, broccoli and collard greens each contain more than 40 milligrams per half-cup (0.1-L) serving. Chestnuts, one of the only nuts that contain ascorbic acid, have 21.8 milligrams per serving of 10 nuts. Perch, goat milk and lowfat yogurt also contain small amounts of the vitamin.