Dietary fat is not the villain

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http://bmj.bmjjournals.com/cgi/content/full/331/7521/906-b

 

BMJ 2005;331:906-907 (15 October), doi:10.1136/bmj.331.7521.906-b

 

 

Europe in transition

Dietary fat is not the villain

 

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

 

Uffe Ravnskov, independent researcher

 

Magle Stora Kyrkogata 9, 22350 Lund, Sweden ravnskov

 

Competing interests: None declared.

 

References

 

1. Zatonski WA, Willett W. Changes in dietary fat and declining

coronary heart disease in Poland: population based study. BMJ

2005;331: 187-8. (23 July.)[Free Full Text]

2. Ravnskov U. The questionable role of saturated and

poly-unsaturated fatty acids in cardiovascular disease. J Clin

Epidemiol 1998;51: 443-60.[CrossRef][iSI][Medline]

3. 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:

153-65.[CrossRef][iSI][Medline]

4. 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:

757-63[Abstract/Free Full Text]

5. Ravnskov U. Diet-heart disease hypothesis is wishful thinking.

BMJ 2002;324: 238.[Free Full Text]

 

 

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