Although very nutritious and high in vitamin C, grapefruit juice is high in acid. It is best to drink small amounts or to dilute grapefruit with water or other juice. The younger and more active the person are the higher metabolism and body’s ability to breakdown acid. For older, less active people grapefruit juice should be drunk in moderation.

Grapefruit should be juiced by hand, rather than using an electric juicer, to prevent any of the white pitch or the peel from being squeezed along with the juice. The pitch and peel can give the juice an unpleasant, bitter flavor. While white grapefruit usually make the best flavored juice, pink or red grapefruit may also be used.
Grapefruit Juice