In 2001, the Cochrane Collaboration published a review of “reduced or modified dietary fat for preventing cardiovascular disease.” The authors combed the literature for all possibly relevant studies and identified twenty-seven that were performed with sufficient controls and rigor to be considered meaningful.*26 These trials encompassed some ten thousand subjects followed for an average of three years each. The review concluded that the diets, whether low-fat or cholesterol-lowering, had no effect on longevity and not even a “significant effect on cardiovascular events.” There was only a “suggestion” of benefit from the trials lasting more than two years. In 2006, the Cochrane Collaboration published a review of multiple-risk-factor interventions—including lowering blood pressure and cholesterol—for the prevention of coronary heart disease. In this case, thirty-nine trials were identified of which ten (comprising over nine-hundred thousand patient years of observation) included sufficient data and were carried out with sufficient rigor to draw meaningful inferences. “The pooled effects suggest multiple risk factor intervention has no effect on mortality,” the authors concluded. Although, once again, a “small” benefit of treatment, perhaps “a 10 percent reduction in CHD mortality,” may have been missed, they added.

If we believe in Rose’s philosophy of preventive medicine, this suggestion of benefit or the possibility that even a “small” benefit was missed still constitutes sufficient motivation to advocate cholesterol-lowering diets to the entire population, as indeed the authors of the first Cochrane review suggested. We could also assume that if a suggestion of a benefit can be induced after two years on such a diet, we might do considerably better after ten or twenty years, although we would still need trials to test that assumption.