I think that is bullshit. Why would doctors, dietitians and nutritionalists recommend it then? So what, it just by passes the digestion tract all together?! Does that mean my breakfast shake packed full of extra protein doesn't get absorbed? Or my Zoloft? Or the asprin I take for headaches? Or that apple I just ate? Does that mean I am just pissing out the iron pill I took? Think about it, that is the most ridiculous claim I have ever heard. Brands don't even matter. There is no difference between taking a generic no name Vitamin, vs. A to Zinc for example. Vitamins and other nutrients are initially absorbed through the stomach wall, but other organs take what they need as well. Any waste that exists the body is simply excess stuff your body doesn't need. Anything that goes into your stomach will be absorbed just the same as food or alcohol. Look it up.
Also I might add, if things are bypassing your stomach and digestive tract, then you need to see a doctor because you could gastrointestinal (I think that's the right word) dumping disorder or a thyroid problem.