Ascorbate

Ascorbate is the metabolite of vitamin C actually used within the body and thus the preferable form of vitamin C. 

Ascorbate (vitamin C) is a vital antioxidant molecule in the brain. However, it also has a number of other important functions, participating as a co-factor in several enzyme reactions including catecholamine synthesis, collagen production and regulation of HIF-1α.

Ascorbate is the superior form of vitamin C for several reasons:

• Ascorbate is the physiological form of vitamin C used by the body.

• Ascorbate is the form of vitamin C that serves as the most powerful water-soluble antioxidant.

Ascorbate can have different qualities. First, it can be “fully reduced," which means its electrons are all in place and ready to be donated for full antioxidant activity.  “Fully reduced” means that it is not already oxidized, even partially. To be “fully reduced” the ascorbate must be processed without exposure to oxygen, light or excess heat.

Second, ascorbate can also be “fully buffered.” A “fully buffered” ascorbate is one that has been combined with small amounts of selected minerals (for example, calcium, magnesium, zinc, potassium). “Fully buffered” ascorbate reduces metabolic acidity and contributes to a life-supporting, slightly alkaline tissue pH.

Ascorbate is transported into the brain and neurons via the Sodium-dependent Vitamin C Transporter-2 (SVCT2), which causes accumulation of ascorbate within cells against a concentration gradient. Dehydroascorbic acid, the oxidized form of ascorbate, is transported via glucose transporters of the GLUT family. Once in cells, it is rapidly reduced to ascorbate. The highest concentrations of ascorbate in the body are found in the brain and neuroendocrine tissues such as adrenal, although the brain is the most difficult organ to deplete of ascorbate. Combined with regional asymmetry in ascorbate distribution within different brain areas, these facts suggest an important role for ascorbate in the brain. Ascorbate is proposed as a neuromodulator of glutamatergic, dopaminergic, cholinergic and GABAergic transmission and related behaviors. Neurodegenerative diseases typically involve high levels of oxidative stress and thus ascorbate has been posited to have potential therapeutic roles against ischemic stroke, Alzheimer's disease, Parkinson's disease and Huntingdon's disease.