Vitamin B6 (pyridoxine) is required for the synthesis of the neurotransmitters serotonin and norepinephrine and for myelin formation. It is not clear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. Vitamin B6 is a water-soluble vitamin. Water-soluble vitamins dissolve in water. The body cannot store them. Leftover amounts of the vitamin leave the body through the urine.
Vitamin C is purely the L-enantiomer of ascorbate; the opposite D-enantiomer has no physiological significance. Both forms are mirror images of the same molecular structure. This discrepancy constitutes much of the basis of the controversy on current recommended dietary allowances. It is countered by arguments that humans are very good at conserving dietary vitamin C, and are able to maintain blood levels of Vitamin C comparable with other simians, on a far smaller dietary intake.
Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols. Vitamin E does not decrease mortality, even at large doses, It does not improve blood sugar control in an unselected group of people with diabetes mellitus or decrease the risk of stroke. Vitamin E has many biological functions. The antioxidant function is considered to be the most important function of vitamin E and is the one it is best known for.
Ascorbic acid is a mild reducing agent. For this reason, it degrades upon exposure to oxygen, especially in the presence of metal ions and light. It can be oxidized by one electron to a radical state or doubly oxidized to the stable form called dehydroascorbic acid. Ascorbic Acid usually acts as an antioxidant. It typically reacts with oxidants of the reactive oxygen species, such as the hydroxyl radical formed from hydrogen peroxide.
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