Compare Diets -- One Lowers Blood Pressure -- Other Extends Life
BestSyndication.com just ran an article with this title authored by Dan Wilson. Wilson argues that the proper test of a dietary intervention is not its affect on an intermediate factor like blood pressure, but whether the dietary change has been shown to extend life.
We agree.
Unfortunately, Wilson makes a few errors and omissions that undermine the argument. He compares a low-calorie diet to the DASH Diet. The only tests of the DASH Diet are for blood pressure; longevity was not measured -- it was, after all, a 30-day trial of a special population (e.g. 60% African American). He states that a "goal (of the DASH Diet) was to reuce sodium intake." This is an error. The DASH Diet held sodium constant -- a major distinguishing feature of this from other interventions. Thus, he concludes in puzzlement asking why advocates of a purportedly low-sodium DASH Diet would continue to recommend sodum reduction in the face of evidence "that showed people who said they limited their salt intake were 37% more likely to die from coronary heart disease or stroke when compared with those who ate more than the US recommended daily allowance of 2,300 milligrams a day (of sodium, he forgot to add)."
We have no quarrel with advocates of calorie restriction. But let's not set up straw men. And let's play square with the facts. The facts are: the DASH Diet is not sodium restricted and the DASH Diet never claimed to reduce mortality (although some of its advocates would have you believe that).
Bottom line: The headline is correct: Aim at extending life, not any intermediate risk factor like blood pressure (or insulin resistance, plasma renin activity, etc.).
