It is wise to be prudent and ATM avoid grain free foods as a whole..HOWEVER since the studies have been VERY limited to date, avoiding an entire line from any manufacturer, is not warranted (due to that study(s)) imo. That limits choices to the Big 4, and removes many other quality foods from consideration. The study(s) bear watching, but were tiny compared to what is needed, and the jury's still out. Otherwise companies like Blue Buffalo (most of their line is grain free these days) would have jumped off the grain free bandwagon a long time ago. In fact if you shop for dog food at a pet store, or Big Box Store, you will be hard pressed to locate anything but grain free (in Nevada, USA anyway)
Any "fads" in dog food should be looked at very carefully, (I avoid fads like the plague, like I did grain free) and no one should just go with the flow.
Do your own research and consult with your vet and anyone else that you personally know; with a Golden or any dog breed for that matter....There are always hidden interests when scouring the net for this type of information.....Too much money at stake for some to play fairly!
As a side note..water from the tap can also be a problem for our dogs. (I use RO only)