Vitamin C, also known as ascorbic acid, is typically obtained from the diet. Small amounts of water-soluble vitamin C are needed to maintain normal body functions (1-3). Vitamin C has been broadly recognized as the most important hydrophilic antioxidant and is a specific cofactor for many enzymatic reactions. Most plants and animals can synthesize vitamin C from D-glucose and D-galactose. However, due to the absence of the enzyme L-gulonolactone oxidase (GLO) in humans and some animal species such as monkeys, guinea pigs, bats, and birds, they are unable to generate endogenous forms of vitamin C (2, 4). For that reason, humans must obtain vitamin C from their diet or take supplements because a total deficiency of vitamin C in humans can result in spongy swollen bleeding gums, dry skin, open sores on the skin, fatigue, impaired wound healing, and depression. Scurvy can occur when healthy individuals consume <10 mg of vitamin C per day. Additionally, some cancers, anemias, and infections have been linked to a vitamin C deficiency (3,5,6). Ascorbic acid is sensitive to air, light, and heat, thus can be destroyed by overcooking and storing food for prolonged periods. In addition, vitamin C is not stored in the body, which is the reason why it must be regularly consumed.The highest levels of vitamin C can be found in the brain and neuroendocrine tissues (7). Ascorbic acid is essential for the maintenance of collagen, which represents almost one-third of the body's total proteins. Collagen is a constituent protein of bones, cartilages, ligaments, cornea and eye lenses, skin, intervertebral discs, teeth, tendons, gums, blood vessels, and heart valves. Ascorbic acid is also essential for the synthesis of muscle carnitine (β-hydroxybutyric acid), which is necessary for the transport of fatty acids in mitochondria for energy production. Ascorbic acid is needed to synthesize catecholamines and ensure optimal functions of oxytocin, vasopressin, cholecystokinin, and alpha-melanotropin (8). Small amounts of ascorbic acid can prevent against the development of scurvy, and the accumulation of high levels of ascorbate in the plasma and tissues has been found to protect against oxidative damage and limit inflammation (8, 9). As previously mentioned, vitamin C concentration is higher in the brain compared to other organs; therefore, it is likely to contribute to maintaining cognitive functions (10). In newborns, vitamin C deficiency leads to memory impairments due to the decreased neurons in the hippocampus (11). In the elderly, optimum vitamin C levels can help reduce the intensity of many degenerative diseases such as Parkinson's disease, perhaps by manipulating dopamine regulation (12,13). Vitamin C deficiency also contributes to a higher risk of stroke and associated complications in the elderly (10,11). It has also been found that smokers are at a higher risk of developing a vitamin C deficiency and may require an additional 35 mg/day of vitamin C to be able to maintain proper vitamin C functions (13).Another clinically import...