Europe in transition: Dietary fat is not the villainBMJ 2005; 331 doi: https://doi.org/10.1136/bmj.331.7521.906-b (Published 13 October 2005) Cite this as: BMJ 2005;331:906
EDITOR—Zatonski and Willett claim that a decrease of saturated fat and an increase of polyunsaturated fat consumption explain the decrease of coronary heart disease in Poland.1 However, ecological data are prone to bias because they are rarely, if ever, adjusted for confounders. In this case they are even contradicted by similar studies in the past. In a review including 103 time periods in 35 countries, I found that in 30 time periods an increased intake of saturated fat was followed by increased coronary mortality, but after 29 other periods with increased saturated fat consumption heart mortality was unchanged in six and decreased in 23.2
Zatonski's and Willett's statement that their finding is supported by epidemiological and clinical evidence is not true either. In a review of all cohort and case-control studies, heart patients had eaten more saturated fat than had healthy controls in three cohorts, but in one cohort they had eaten less, and in 22 cohorts and in six case-control studies no difference was found.2 No cohort study or case-control study has found that coronary patients have eaten fewer polyunsaturated fats either; on the contrary, three cohort studies found that they had eaten more than the healthy controls, and in 29 studies no difference was found.2
The absence of an association between fat intake and coronary disease was recently confirmed in a large Swedish population study.3 No association has been found either between intake of dietary fats and degree of atherosclerosis at necrotopsy.2 Most importantly, two meta-analyses of all controlled, randomised dietary trials, in which the only type of intervention was a lowering of dietary saturated fats and an increase of dietary polyunsaturated fats, found that the total number of deaths was identical in the treatment and the control groups.2–5
Competing interests None declared.