Tunnel vision is described as the loss of peripheral vision resulting in a constricted circular tunnel-like field of vision. This week has seen a rash of newspaper articles on salt and hypertension in children that precisely reflects that idea. Stemming from the work of MacGregor and He of St. George's University of London and published in the November issue of Hypertension, a number of journalists have parroted the view that reducing salt intake is the single most important path to the future health of all people. Their research, found that a significant reduction of salt intake in children will bring down their systolic and diastolic blood pressures by as much as 1 millimeter of mercury each.
Dr. MacGregor has long espoused salt reduction as the silver bullet for hypertension and has published a number of books: The salt-free diet book; The Low-salt Diet Book; and Salt, Diet and Health: Neptune's Poisoned Chalice, on this issue. Like other researchers focused on reduction of salt consumption as the one answer to hypertension, he believes that research results contrary to his own are tainted by industry or the international salt conspiracy. Since the drop in blood pressure in this study was found to be small, the authors rationalized it by speculating that if it was extended into adulthood, it would have major public health implications in preventing cardiovascular disease in the future. Speculation comes easy to those with committed views, however, as Samuel Johnson once said, "When speculation has done its worst, two and two still make four."
No one doubts the lifelong health benefits of eating more fruits and vegetables as recommended in the government's 5 a Day program or following the principles of the DASH diet for those concerned with hypertension. Rather than extolling the virtues of consuming more fruits and vegetables as the most effective and enduring path to improved health and reduced hypertension for people of all ages - MacGregor and company cannot get away from their singular focus on salt - a constricted, tunnel-like point of view. Could it be because a small amount of salt makes bitter vegetables so much more palatable for everyone, particularly youngsters and would result in far greater benefits (see, And Now For Something Completely Different.. .)? That might contradict everything they stand for.
And herein lies the problem. Scientists who are committed to a single idea can be very damaging. Francis Bacon, the father of modern science insisted that knowledge had to derive from dispassionate scientific experimentation, rather than the musings and speculations of philosophers. Zealots committed to a single idea are, almost by definition, incapable of objective science - neither in the design of proper experiments nor in the interpretation of results. The danger is that they parade around under the mantle of science and will never recognize their own bias. We see this everywhere - advocacy groups proclaiming to pursue science in the public's interests, yet subjectively pick and choose selective bits and pieces of data to serve the objects of their advocacy. Believing in science means practicing science and that means being objective. It leaves no room for individuals committed to a single idea and any information or advice that they develop must be treated with the intellectual reserve and caution it deserves - particularly when it come to the health of our children. Journalists should understand this before they serve as a vehicle for the dissemination of myth-information.
