Royal Canin is being sued for poisoning dogs with an overdose of vitamin B. 

• http://www.cbc.ca/canada/british-columbia/story/2007/03/20/pet-food-lawsuit.html
  
• http://www.cnw.ca/fr/releases/archive/March2007/20/c4739.html

Effects of Vitamin D overdose in people http://www.cnw.ca/fr/releases/archive/March2007/20/c4739.html

Caution here it's wikipedia http://en.wikipedia.org/wiki/Hypervitaminosis_D  I find it OK for information, but since anybody can edit wikipedia, sometimes folks with agendas (perhaps the a vitamin D maker) can change and do anything they want.  Never fully trust ANYTHING on Wikipedia.  Verify for yourself.

OK, but a veterinary web site says newer rat poisons actually use vitamin D as an active to trigger hypercalcimia http://www.marvistavet.com/html/body_hypercalcemia.html, and specifically mentions dogs getting into it.

OK, I'm not YET going to jump all over Royal Canin too much because it seems like a long-shot that these folks have a case to me.  However, I've noticed all kinds of "gimmicks" in dog food lately.  Purina is putting out dog food made of and marketed as you know, the four food groups.  (Those are for PEOPLE; dogs are different.)  They put fish oil and yogurt in ONE.  Both Eukanuba and Purina ONE have "natural" (or is it organic) variations.

This has to come from the marketing departments.  The best reason to feed yogurt, for instance, is the live cultures (critters, really) that MIGHT help with digestion in a dog.  (The only reason I say might is Amanda says it does, but I'm not buying it.  As a lactose intolerant man, I can't buy into putting lactose on top of a rumbling tummy, or that yogurt cultures can survive a human or dog stomach.)  Of course, you couldn't have a dry dog food that would survive at room temperatures if you had live cultures in it, so I can't tell you what it's for.

If Royal Canin did have excessive Vitamin D, I'd bet it was a side effect of trying to get some other ingredient into the food.  Like the "natural" food preservatives.

80% of the dogs out there would do just fine on a "normal" food for "normal" dogs.  Why do we have so many flavors and formulas?