I don't think it's totally benefit-less, but certainly no where near as "brainboosting" as it's purported.

But many other natural substances DO have some ground to stand on. To use your examples, Acai berries are very high in antioxidant compounds. Now, how effective these are is certainly up for debate, but they are in fact full of them. And damned tasty. Shark cartilage has exactly what's in YOUR cartilage. No, it won't cure your osteoarthritis or any nonsense like that...but it IS a legit treatment for symptoms. You can't even say "oh it's just placebo effect", because horses and dogs aren't exactly prone to placebo effect I have personally seen it have good effects in our dressage horses. Cure? No. Treatment? Yes. Just like you wouldn't use tylenol to "cure" a fever, it'd be erroneous to think cartilage supplements (from sharks or otherwise) would "cure" arthritis...but just like tylenol, it will help alleviate symptoms.

I'm not saying all natural additives hold such ground, but many do have legitimate applications and to entirely disregard them out of hand is just as ignorant as accepting them without question.