Here's some of the product info for the protein drink they had me on. I'm not promoting it or anything, but it gives info on why it's used...which looks to also back up what Russ mentioned. The product is UltraClear Plus by Metagenics. Myself, I'm using a Whey protein drink now.

Provides the same great macro- and micronutrient base formula and benefits as UltraClear, but with added support for those who are "imbalanced detoxifiers"—people with low Phase II activities.

Imbalanced detoxification may be due to genetic predisposition, a history of chronic nutrient insufficiency, and/or toxin overload, which can result in a buildup of reactive oxygen intermediates and a subsequent increase in symptoms and/or tissue damage.

Features added glycine, taurine, sodium sulfate, and catechins from decaffeinated green tea to better support Phase II activities.

Safe for long term use in individuals with chronic exposure to toxins.