Critical Reasoning Question 23: Heart Attack

According to a recent study, a diet that is free of meat and dairy products greatly reduces the risk of suffering a heart attack.  The study cites the fact that only 10% of those who consume such a diet suffer a heart attack at some point in their lives.

Which of the following would  most seriously weaken the argument above?

A.       Diets free of meat and dairy are low in calcium, which can lead to bone density decreases.

B.        Those who consume only dairy but not meat are twice as likely to suffer a heart attack as those who consume neither meat nor dairy.

C.      Some people who consume neither dairy nor meat suffer two or more heart attacks over the course of a lifetime.

D.      Meat and dairy products are high in low-density cholesterol, which is known to harden arteries and cause other heart problems.

E.       7% of those who consume dairy and meat regularly suffer heart attacks over the course of their lifetime.

Think you know the answer?

The correct answer is E.

The conclusion here is that a diet free of meat and dairy products greatly reduces the risk of heart attack, based on the evidence that only 10% of those who omit meat and dairy from their diets suffer heart attacks.  The assumption is that more than ten percent of those who do eat dairy and meat suffer from heart attacks.  If we knew that those who eat meant and dairy are less likely to suffer heart attacks, the assumption would be contradicted and the argument weakened.

(A)   is out of scope.  (B) nearly strengthens the argument.  (C) does little to affect the argument in either direction.  (D) strengthens the argument and (E) matches our prediction exactly.