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Title: Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European prospective investigation into cancer and nutrition study

Authors: P Guallar-Castillón, F Ridr?guez-Artalejo, E Lopez-Garcia, L Leon-Munoz, et al

Reference: BMJ 2012; published online 24 January 2012
http://bit.ly/ABwD3M

Reviewer: Robert Goldberg, PhD, Contributing editor, ProCor; Professor of Medicine and Epidemiology, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA

Reviewer comments: There is some controversy about the role in which inherently healthy foods may be prepared in an unhealthful manner that can lead to the development of coronary heart disease (CHD), though there are limited data in this area. Frying may be one such negative method of food preparation, though few studies have examined this biologically plausible, albeit complex, association.

The results of the present analysis, using data from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition, fail to convincingly demonstrate an association between fried food consumption and the risk of developing CHD or dying from any cause of death. The authors highlight the possible underlying mechanisms that might be involved for a putative association between the intake of fried foods and its effects on the underlying pathology leading to the eventual development of CHD.

The results of this large prospective study provide "encouraging" findings that the consumption of fried foods may not be associated with an increased risk for CHD. These results need to be tempered, however, since they were based in a Mediterranean country (Spain) where olive and sunflower oils are commonly used for cooking and eating and a single determination of dietary intake was carried out at the time of original study enrollment. This association should be examined in other datasets in different population settings to provide more definitive evidence about the possible adverse health effects on CVD associated with the consumption of fried foods.

Until more proof can be provided, however, it is prudent for individuals to limit their intake of fried foods and follow a heart healthy diet of whole grains, nuts, fruits and vegetables, and lean portions of fish, chicken, and turkey. In addition, participation in a program of regular physical activity and maintenance of optimal weight remain cornerstones of heart healthy lifestyle practices and proven modalities to reduce the risk of CHD.

Purpose of study: To examine, in a longitudinal manner, the association between the consumption of fried foods and the risk of CHD in a Mediterranean country

Location of study: Madrid, Spain

Study design: Longitudinal cohort

Results: The authors used data from the Spanish cohort enrolled in the European Prospective Investigation into Cancer and Nutrition (EPIC). This cohort included more than 41,000 healthy adults age 29-69 years at the time of enrollment into this longitudinal investigation in the early to mid-1990s.

Participating men and women were recruited from different regions throughout Spain in order to maximize variability in diet and nutrient intake. Food consumption was assessed through use of an extensive food frequency dietary questionnaire with more than 500 different foods assessed. Information on the type of cooking methods utilized was collected including the type of oil used for cooking and frying. Information was also collected about a variety of socio-demographic factors, prior medical history, height and weight, and other lifestyle practices that may affect the risk of CHD.

The present analyses were restricted to patients without a history of CHD at the time of baseline enrollment. Other exclusion criteria were applied to the study sample, resulting in a final analytic sample of 40,757 men and women. The average age of this population was approximately 50 years, two-thirds were women, approximately one-quarter were current smokers, and one-fifth were classified as sedentary.

On average, nearly 140 grams of fried food were consumed on a daily basis, or 7% of the total amount of food consumed. Men were more likely to consume fried foods than women and approximately three in every five participants used olive oil for frying.

Over a median follow-up of 11 years, a total of 606 definite CHD events occurred in the study sample: there were an additional 712 possible or probable CHD events and 1135 deaths from all causes.

In examining the association between quartiles of fried food consumption and risk of a definite CHD event, no statistically significant multivariable adjusted association was observed. The multivariable adjusted hazard ratio of CHD for the highest versus lowest quartile of fried food consumption was 0.94. Fried food consumption was also not associated with the risk of definite, possible, or probable CHD events (HRs ranged from 1.04 to 1.08) nor with all-cause mortality. Compared with individuals in the lowest quartile of fried food consumption, persons in the highest quartile of fried food intake had a hazard ratio of 0.93 with regards to total mortality. Similarly, specific fried food groupings, such as fried fish, meat, or potatoes, were not associated with an increased risk of CHD or all-cause mortality.