Unsaturated vs Saturated Fats: How Do Specific Dietary Fats Affect Mortality?

Different dietary fats affect all-cause and cause-specific mortality in different ways, with saturated and trans-fat associated with increased mortality risk and unsaturated fats associated with reduced mortality risk, according to the results of a recent study.

While previous research has drawn connections between specific dietary fat types and cardiovascular disease (CVD), research remains limited on the link between specific dietary fats and mortality.

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To investigate this further, the researchers examined data from 83,349 women from the Nurses’ Health Study from July 1, 1980, to June 30, 2012, and 42,884 men from the Health Professionals Follow-up Study from February 1, 1986, to January 31, 2012. All participants were free of CVD, cancer, and diabetes at baseline.

The researchers assessed dietary fat intake at baseline and for every 2 to 4 years and tracked mortality via vital records of states and the National Death Index.

Overall, 33,304 deaths occurred during the study period.

The researchers found that dietary total fat compared with total carbohydrates was inversely associated with total mortality. High saturated fat intake was associated with an 8% increase in total mortality, and high trans-fat intake was associated with a 13% increase in mortality.

However, high intake of polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) reduced mortality risk by 19% and 11%, respectively. Also, replacing 5% of energy from saturated fats with equivalent energy from PUFA and MUFA reduced mortality risk by 27% and 13%, respectively.

“Different types of dietary fats have divergent associations with total and cause-specific mortality,” the researchers concluded. “These findings support current dietary recommendations to replace saturated fat and trans-fat with unsaturated fats.”

—Amanda Balbi


Wang DD, Li Y, Chiuve SE, et al. Association of specific dietary fats with total and cause-specific mortality [published online July 5, 2016]. JAMA Intern Med. doi:10.1001/jamainternmed.2016.2417.