#20 - Newspaper article: People who take vitamin C

[afinelli]

Why does D win over B in this question? I had it down to these D and B, and went for B because I thought the fact that other dietary changes can cause reduction in risk of heart disease would mean Vitamin C takers aren't necessarily healthier than average.
Thanks for any help!

[Nikki Siclunov]

You are correct in that (B) and (D) are the strongest contenders. However, notice the conclusion (first sentence): people who take vitamin C tend to be healthier than average. The study, however, only investigated the relationship between vitamin C and heart disease. Since our overall health depends on a number of factors other than heart disease, there is a logical gap between the premise and the conclusion. By presenting a downside to the consumption of vitamin C supplements, answer choice (D) shows that people who take vitamin C supplements would not necessarily be healthier than average (even if they have a lower average risk of heart disease).

By contrast, answer choice (B) suggests that there may be other dietary changes that can reduce the risk of heart disease just as much as the consumption of vitamin C can. That does not necessarily mean that the consumption of vitamin C supplements would be ineffective. Remember - the author never argued that vitamin C supplements are the only way to reduce the risk of heart disease; just because there are other means of achieving the same goal does not invalidate the article's recommendation.

[afinelli]

Very helpful (and now seems so obvious!). Thanks much.

[Basia W]

Good evening,

Does this answer demonstrate causal reasoning? I chose answer B in hopes of providing an alternate cause (the possibility that Vitamin C is equal to other dietary changes) for the effect of lowering heart disease. However the stimulus does state that these supplements "tend" to make people healthier so is this not strong enough for "causing" something to happen?
Answer D also stated "reduce slightly" but I may have overlooked the fact that the correct answer only has to weaken the argument not destroy it...

Thank you for your time and explanations,

best,

Basia

[Lucas Moreau]

Hello, Basia,

For Weaken questions, you are not just trying to weaken the conclusion itself, you are weakening the link between premises and conclusion. You're trying to show that the premises do not lead to the conclusion, even if they're all accepted as true.

In this case, the conclusion is that people who take vitamin C tend to be healthier on average. The premise in support of this showed that people who took vitamin C supplements had a lower risk of heart disease.

B doesn't show that vitamin C does not make people healthier, it just asserts that the healthful effects of vitamin C aren't any better than some others. That doesn't weaken the link between premises and conclusion, so much as it offers a possibly superior answer to the problem. But that's not how LSAT questions are solved!

D, meanwhile, shows that vitamin C may be a net loss - though a person might be healthier for a lower risk of heart disease through vitamin C, if his resistance to infectious diseases is also reduced, then his overall level of health may be lowered, rather than raised, by the vitamin C. Even if you have a slightly reduced risk of heart disease, you're not "healthier" if you have colds and flu all the time, lol!

Hope that helps,
Lucas Moreau

[Basia W]

Hello,

Thank you for clarifying that! That makes more sense. I will focus on the link between the premises and the conclusions and the conclusion not necessarily following.

Best,

Basia