Fish four times a week? What about the mercury?
It depends greatly on the type and source of the fish. For example, a premium fresh tuna steak will generally have much more mercury than cheap canned chunk light tuna. Domestic farmed catfish will have lower levels than some expensive wild fish.
Deep sea fish doesn't have it. I eat tuna 4-5 times a week. LOL, I had a test for mercury and on a scale of 0-15, I was a 2. So....
Maybe why it's only 4X per week instead of daily? That's what popped into my mind as I read it.