PrepTest 127, Section 2, Question 6
Dietitian: High consumption of sodium increases some people's(39 more words not shown)
Which one of the following(8 more words not shown)
- AFresh fruits and(6 more words not shown)
- BFood processing businesses(9 more words not shown)
- CPotassium is the(9 more words not shown)
- DPotassium in fruits(7 more words not shown)
- EFresh fruits and(10 more words not shown)
Reading the argument
The dietitian says high sodium consumption raises some people's risk of heart disease. My first reaction is to wonder why those people wouldn't simply reduce their sodium intake. But the recommendation has a particular aim: maintaining cardiac health without doing that. We need to evaluate it on those terms.
Potassium apparently helps prevent sodium's harmful effects. The dietitian therefore recommends fresh fruits and vegetables instead of canned or frozen ones. Still, where else could someone get potassium? Could a supplement provide it? If potassium is doing the useful work, I want to understand why this particular source is recommended.
What we’re looking for
The stem asks for an assumption the argument requires. Keep the proposed benefit in view: potassium. We need a fact that makes the recommendation follow from that benefit, while remembering that an assumption required for this argument need not rule out every other way to stay healthy.
Working the answers
- A
We aren't told that potassium must outnumber sodium to help. Imagine, purely as a hypothetical, that one unit of potassium could counteract the harmful effect of a million units of sodium. That would leave the proposed benefit intact even if fresh produce contained more sodium than potassium. The argument doesn't establish the ratio A requires.
- B
Processing businesses might add sodium, but that isn't required by the argument. The dietitian bases the recommendation on potassium's benefit while holding sodium consumption steady. There could be a relevant potassium difference even if no sodium were added during processing.
- C
Potassium need not be the only helpful mineral. Another mineral could also help prevent sodium's harmful effects without undermining the reason for getting potassium. A recommendation based on one benefit doesn't require that no other substance offer that benefit.
- D
The claim is about cardiac health, not the absence of other side effects. Potassium could have some unwanted effects and still help prevent the particular harm under discussion. We are not given a general claim that potassium has few negative effects.
- ECorrect
This identifies the comparison that matters: fresh produce versus canned or frozen produce. If they contained equal amounts of potassium, why would potassium's benefit be a reason to prefer fresh produce? The dietitian's stated basis for that preference requires fresh fruits and vegetables to provide more potassium. My initial question concerned other sources; E pinpoints the missing advantage of the recommended source over the alternatives actually named.
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