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PAPERS: Witold A Zatonski and Walter Willett Changes in dietary fat and declining coronary heart disease in Poland: population based study BMJ 2005; 331: 187-188 [Full text]

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Dietary fat is not the villain

Uffe Ravnskov   (26 July 2005)

Dietary fat is not the villain 26 July 2005
Uffe Ravnskov, MD, PhD, independent researcher Magle Stora Kyrkogata 9, 22350 Lund, Sweden Send response to journal: Re: Dietary fat is not the villain	Dr. Zatonski and Professor 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 prey 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 heart 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 coronary 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 6 case-control studies no difference was found.2 No cohort or case control study has found that coronary patients have eaten less polyunsaturated fats either; on the contrary, three cohort studies found that they had eaten more than had their heart-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 autopsy.2 Most important, two meta-analyses of all controlled, randomised dietary trials, in which the only type of intervention was a lowering of dietary saturated fats and/or an increase of dietary polyunsaturated fats found that the total number of deaths was identical in the treatment and the control groups.2,4,5 As usual, epidemiological studies are bad as proof, but excellent for falsification.  Zatonski WA, Willett W. Changes in dietary fat and declining coronary heart disease in Poland: population based study. BMJ 2005; 331:187-188 Ravnskov U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease. J Clin Epidemiol 1998;51: 443-460.  Leosdottir M, Nilsson PM, Nilssson JÅ, Månsson H, Berglund G. Dietary fat intake and early mortality patterns – data from The Malmö Diet and Cancer Study. J Intern Med 2005; 258: 153–165. Hooper L, Summerbell CD, Higgins JPT, Thompson R, Capps NE, Davey Smith G, et al. Dietary fat intake and prevention of cardiovascular disease: systematic review. BMJ 2001; 322: 757-763 Ravnskov U. Diet-heart disease hypothesis is wishful thinking. BMJ 2002; 324: 238. Competing interests: None declared