Vitamin C, also known as ascorbic acid is a basic essential nutrient that has numerous functions in the human body including acting as an antioxidant, collagen formation, cofactor required both in catecholamine biosynthesis and in adrenal steroidogenesis, the immune system, repair of tissue and wound healing.
It always pains me to see people rushing out to mega-dose massive doses of synthetic ascorbic acid supplements, especially when there are so many healthy natural Vitamin C rich foods, herbs and botanicals to choose from.
Natural food and herbal sources of Vitamin C such as Acerola, Amla Berry and Rosehips for example also tend to be more stable than synthetic ascorbic acid supplements.
Part of the reason why natural food sources of Vitamin C tend to be more stable than synthetic Vitamin C supplements is because herbs and whole-foods contain many supportive bioflavonoids and other antioxidants such as tannins, which basically help to keep the Vitamin C stable by preventing oxidation.
This is part of the benefit to consuming natural whole-food and herbal sources, as you also obtain many other highly valuable syngeristic nutrients and phyto-chemicals in the process.
The current recommended dietary allowance (RDA) for vitamin C for adult nonsmoking men and women is 60 mg/d, which is based on a mean requirement of 46 mg/d to prevent the deficiency disease scurvy. 
The optimal RDA for Vitamin C for optimum reduction of chronic disease risk in nonsmoking men and women, however is much larger and previous research indicates it to be in the region of 90-100mg/d. With a suggest RDA in the region of 120 mg vitamin C/d.
Here are five of my favorite natural dietary sources of Vitamin C.
1. Acerola Cherry
The ripe red cherry like fruit is an extremely rich source of Vitamin C and other nutrients such as Vitamin A, B-complex Vitamins, aswell as phyto-nutrients such as carotenoids and bioflavonoids.
Acerola cherry contains about 1677 mg of vitamin C per 100 g of fruit.
It is for this reason Acerola Cherry Extracts have become a very cheap and popular supplement to get well over 100% of the RDA for natural Vitamin C in a single capsule.
2. Amla Berry
Whilst Amla is not as rich a source of Vitamin C as the likes of Acerola and Camu Camu. The research has found that the Vitamin C in amla fruit is 12 times stronger than synthetic ascorbic acid and more stable once again due to being bonded with tannins, which help protect the Vitamin C from degradation from heat and light.
Studies have also found that Amla may have other potential health benefits including antioxidant, anti-bacterial, anti-inflammatory, antidiabetic, antiulcerogenic, hepatoprotective, hypolipidemic, gastroprotective and chemopreventive benefits.
3. Kiwi Fruit
One single medium kiwi fruit contains around 70.5mg of Vitamin C, which is around 117% of the recommended daily value(DV).
Kiwis are not just packed with Vitamin C, they are also a good source of dietary Fiber, Vitamin E (Alpha Tocopherol), Potassium, Copper and Vitamin K.
4. Bell Peppers
Bell Peppers are chock full of Vitamin C and one medium red bell pepper contains around 152mg of Vitamin C, which is 253% of the DV(Daily Value).
Research has found Bell Peppers to contain a variety of bioactive phyto-nutrients that have high antioxidant capacity including carotenoids and flavonoids such as quercetin, luteolin, and capsaicinoids.
Rosehip is known as having a high content of vitamin C (300-4000 mg/100 g) in relation to the other fruits and vegetables. 
In addition, Rosehip contains other vitamins, minerals, carotenoids, tocopherols, bioflavonoids, tannins, pectin, sugars, organic acids, amino acids and essential oils.
Traditionally the consumption of rosehip fruits, flowers, leaves and buds has been said to prevent and treat cardiovascular and gastrointestinal diseases.
 Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans
 Influence of Processing on Vitamin C Content of Rosehip Fruits
The information in this article has not been evaluated by the FDA and should not be used to diagnose, cure or treat any disease, implied or otherwise.