(HealthDay News) – Substitution of dietary saturated fatty acids with linoleic acid seems to be associated with increased risks of all-cause mortality, coronary heart disease, and cardiovascular disease, according to research published online Feb. 5 in BMJ.

Christopher E. Ramsden, MD, from the National Institutes of Health in Bethesda, MD, and colleagues evaluated recovered data from the Sydney Diet Heart Study, conducted in 1966–1973, and an updated meta-analysis including these data to assess the effectiveness of replacing dietary saturated fat with omega 6 linoleic acid. Participants included 458 men aged 30–59 years with a recent coronary event who were randomized to the intervention (221 men; replacement of dietary saturated fat with omega 6 linoleic acid) or control (237 men; no specific dietary instruction or study foods).

The researchers found that the death rate was significantly higher in the intervention group than among controls (hazard ratios [HRs]: all cause death, 1.62; cardiovascular disease, 1.70; coronary heart disease, 1.74). In a meta-analysis of trials of linoleic acid including these recovered data, there was a non-significant trend toward increased risk of death from coronary heart disease (HR, 1.33; P = 0.06) and cardiovascular disease (HR, 1.27; P = 0.07).

“Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established,” the authors write. “These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.”

The Life Insurance Medical Research Fund of Australia and New Zealand provided grant support for the Sydney Diet Heart Study.

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