"you can make these delicious by adding a fresh grapefruit." - ldsfireguy
Every part of the grapefruit is remarkable for its health giving qualities; including the white part of the rind and extract of its seeds. Most pharmaceuticals for heart conditions are voided in the presence of grapefruit; confirming the power of that fruit. Because of that I would beware of eating grapefruit without consulting with the pharmacist about the drugs being taken. Just in case.
...but you are very correct in that the green drink is so much better with added grapefruit.