Switch from saturated to unsaturated FA lowers mortality risk

Replacing saturated fatty acid (SFA) with unsaturated fatty acids, particularly from plant sources, and eliminating dietary trans fatty acid (TFA) can help prevent premature death, according to a study.

A total of 20,571 deaths were recorded through 2020 among 65,179 adults from the Nurses’ Health Study and Health Professionals Follow-up Study who were free from cardiovascular disease, cancer, and diabetes at baseline in 1994.

The authors assessed diets every 4 years through validated questionnaires and calculated hazard ratios (HRs) with 95 percent confidence intervals (CIs) using Cox proportional hazards models.

An energy increment of 5 percent in total fat intake resulted in 5-percent lower all-cause mortality risk (HR, 0.95, 95 percent CI, 0.93‒0.96; isocaloric comparison was total carbohydrate).

A 5-percent increment in energy intake from polyunsaturated (PUFA) and monounsaturated fatty acid (MUFA) reduced all-cause mortality by 17 percent (HR, 0.83, 95 percent CI, 0.78‒0.89) and 9 percent (HR, 0.91, 95 percent CI, 0.87‒0.94), respectively.

On the other hand, a 1-percent increase in energy intake from TFA led to a 10-percent higher risk of all-cause mortality (HR, 1.10, 95 percent CI, 1.04‒1.17; p_trend≤0.001). Changes in SFA, however, showed no association with all-cause mortality.

Of note, “[i]ncreases in intakes of linoleic acid, marine n–3 PUFA, and MUFA from plant sources were each significantly associated with lower all-cause mortality,” the authors said.

Substitution analyses revealed a 19-percent reduced all-cause mortality when replacing 5-percent energy from SFA with PUFA (HR, 0.81, 95 percent CI, 0.75‒0.87), as well as an 11-percent lower all-cause mortality when replacing 0.3-percent energy from SFA with marine n‒3 PUDA (HR, 0.89, 95 percent CI, 0.84‒0.93).

“Isocaloric substitution of SFA by PUFA, particularly marine n–3 PUFA, was associated with lower mortality due to cardiovascular, neurodegenerative, and respiratory diseases,” the authors said.