Food processing businesses often add sodium to foods being canned or frozen. Potassium is the only mineral that helps to prevent sodium's malign effects. Fresh fruits and vegetables contain more potassium than do canned or frozen ones. Fresh fruits and vegetables contain more potassium than sodium.
Dietitian: High consumption of sodium increases some people' s chances of developing heart disease. To maintain cardiac health without lowering sodium consumption, ttherefore, these people should eat fresh, rather than canned or frozen, fruit and vegetables, since the potassium in plant foods helps to prevent sodium' s malign effects.
Which one of the following is an assumption required by the dietitian's argument?