Consumption of trans fats and estimated effects on coronary heart disease in Iran.
OBJECTIVE
To investigate the consumption of industrial trans-fatty acids (TFAs) in Iranian homes and the proportion of coronary heart disease (CHD) events in Iran attributable to such intake.


METHODS
The consumption of industrial TFAs was determined using (1) detailed in-home assessments of dietary intake among 7158 urban and rural households containing 35 924 individuals and (2) gas chromatography to determine TFA contents of the most commonly consumed partially hydrogenated oils. The population-attributable risk for CHD owing to TFA consumption was calculated on the basis of (1) documented effects of TFAs on total:high-density lipoprotein (HDL) cholesterol in randomized controlled dietary trials and (2) relationships of TFA intake with incidence of CHD in prospective observational studies.


RESULTS
Partially hydrogenated oils were used extensively for cooking in Iranian homes with average per-person intake of 14 g/1000 kcal. TFAs accounted for 33% of fatty acids in these products, or 4.2% of all calories consumed (12.3 g/day). On the basis of total:HDL cholesterol effects alone, 9% of CHD events would be prevented by replacement of TFA in Iranian homes with cis-unsaturated fats (8% by replacement with saturated fats). On the basis of relationships of TFA intake with CHD incidence in prospective studies, 39% of CHD events would be prevented by replacement of TFA with cis-unsaturated fats (31% by replacement with saturated fats). These population-attributable risks may be overestimates owing to competing risks and because not all the fat used for cooking might actually be consumed. If actual TFA consumption were only half as large, the estimated proportion of CHD events prevented by TFA elimination would be 5% on the basis of total:HDL cholesterol effects and replacement with cis-unsaturated (4% for replacement with saturated fats), and 22% on the basis of prospective studies and replacement with cis-unsaturated fats (17% for replacement with saturated fats). These estimates do not include possible additional benefits derived from replacing TFAs with vegetable oils containing n-3 fatty acids.


CONCLUSIONS
Intake of TFAs is high in Iranian homes and contributes to a sizeable proportion of CHD events. Replacement of partially hydrogenated oils with unhydrogenated oils would likely produce substantial reductions in CHD incidence.


BACKGROUND
National Heart, Lung and Blood Institute, National Institutes of Health, USA. National Nutrition & Food Technology Research Institute, Tehran, Iran.
Mozaffarian
D
D
The Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. dmozaffa@hsph.harvard.edu
Abdollahi
M
M
Campos
H
H
Houshiarrad
A
A
Willett
W C
WC
D000293:Adolescent; D000328:Adult; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D004034:Diet Surveys; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006865:Hydrogenation; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D012307:Risk Factors; D044242:Trans Fatty Acids / Q000008:administration & dosage* / Q000009:adverse effects
D008076:Cholesterol, HDL; D004042:Dietary Fats, Unsaturated; D044242:Trans Fatty Acids; D002784:Cholesterol