Present in high levels in red peppers, broccoli and grapefruit juice, it is also known as ascorbic acid.  
Studies have connected low levels of this substance to increased lead retention in the blood, while it also may convert cholesterol into bile acids.  Its primary functions are to synthesize carnitine and the neurotransmitter, norepinephrine.  Deficiency of this vitamin leads to the loss of teeth and easy bruising, while it has been shown to reduce the duration of the common cold.  Present in high levels in red peppers, broccoli and grapefruit juice, it is also known as ascorbic acid.  For 10 points, name this vitamin that prevents scurvy and is present in orange juice.
Studies have connected low levels of this substance to increased lead retention in the blood, while it also may convert cholesterol into bile acids.  
Vitamin C (or Ascorbic Acid)