R.A. Stallones: A Balanced View of the Diet-Heart Controversy in 1980

[ed. This editorial by a leading epidemiologist of our times, R.A. Stallones, represents one of the more thoughtful, rational, and scientific dissections of the Diet-Heart situation around 1980. This does not make it the truth. It is historic, nevertheless, because of its different interpretation than most cardiovascular epidemiologists placed on the evidence. It is also, to an extent, based on some misapprehensions about the design of studies, including the Seven Countries Study which was not based on a choice of high and low incidence countries but rather on a choice of high and low fat intake.]

A number of other exceptions could be taken concerning the reality of threatened “large economic dislocations” of recommendations for diet changes. Nevertheless, its conclusions and the tone and analysis were unusual for its time and place, balance and perspective.

Stallones was particularly hard on such official recommendations as “suggested but not unequivocal reduction,” as a syntactical swinging door, so that one may slip in or out depending on how matters shape up.” And he quotes the pontifications of George Mann: “No diet therapy has been shown effective for the prevention of coronary disease,” commenting: “One may, perhaps should, disagree with George Mann’s conclusion, but as an exercise in declarative English expression his statement is far superior to a suggestive, but not unequivocal, reduction.”

Finally, we quote Stallones’s conclusions:

“Epidemiological research has produced consistently strong associations between serum cholesterol and ischemic heart disease, but contradictory findings for the relations between diet and serum cholesterol and between diet and ischemic heart disease. For the latter two, the dietary hypothesis is generally not supported in comparisons of individuals.”

“The discrepancy can be resolved totally if the argument is accepted that the problem arises because of the variability in measurement of diet, serum cholesterol, and disease…Debate on this issue could be brought to abrupt closure by establishing the efficacy of dietary modification in controlled experiments.”

“In the best of all possible worlds, we could now look back over this trail of research findings and assessments, make due allowance for the biases that may have crept into this presentation, and plucked the flower of truth from the nettle of confusion. However, in this instance truth is not readily apparent, and we must instead accept a better appreciation of the reasons for widely divergent perceptions of whatever truth may lie beneath the welter of data. Judgments on matters such as this are made in three spheres – personal, scientific, and public – and they need not agree.”

Personal position…”one of the problems at present is that a person may not be able to make well-informed choices when the messages from scientists and policy makers are conflicting and uncertain.”

Scientific posture…”consensus among scientists is uncommon, but that we are now far from consensus is testimony to the ambiguity of the information base.”

Public policy…”in this situation, the public policy issue is whether or not to promote large-scale changes in the diet of the population of the United States. To fail to promote dietary change is as firmly a public policy decision as to promote a change, for a primary characteristic of public policy is that a neutral position, such as deciding to wait for scientific clarification, is not truly neutral.”

“Since the evidence leaves a significant number of experts unconvinced, public policy arguments tend to revolve around other issues, such as whether dietary change is likely to be harmful. Although the prudent diet that is widely recommended is probably innocuous, concerns are expressed with respect to possibly deleterious effects of low serum cholesterol, and about the wisdom of imposing a restricted diet in infancy. Furthermore, massive change in the national diet calls for aggressive promotion and large economic dislocations. Whether this is an important issue depends, of course, on the side of the economic fence one occupies. As long as the scientific questions are unresolved, the public policy debate must continue.”

The truly bright spot in all of this is that while the debate goes on, the mortality rates for ischemic heart disease continue to decline as a log-linear function. This trend, which dates back to the mid 1960’s, gives us assurance that while we may not be right, we cannot be distressingly wrong if we hesitate before taking aggressive action to alter the dietary customs of the nation.” (Henry Blackburn)

Reference

Stallones, R.A. 1983. Ischemic heart disease and lipids in blood and diet. Annual Review of Nutrition 3: 155-85.