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On August 14, 2024, we reported on findings from a study published in JAMA Internal Medicine that examined the associations of dietary plant and animal fat intake with overall mortality and cardiovascular disease (CVD) mortality.
The study
Investigators examined dietary and health data from 1995 to 2019 as part of the NIH’s AARP Diet and Health Study Cohort. A total of 407 531 individuals (56.9% men; mean age, 61.2 years) were included in the current study.
Dietary fat intake was assessed using a validated food frequency questionnaire (FFQ) that collected information on specific food sources of dietary fats. The FFQ included 124 dietary items and portion sizes, based on the US Department of Agriculture’s Continuing Survey of Food Intakes by Individuals. Total dietary fat intake included both plant sources (ie, grains, nuts, legumes, and vegetable oils) and animal sources (ie, red and white meat, dairy foods, and eggs).
Participants were divided into 5 quintiles, where each quintile represented 20% of the study population, ranked from the lowest (quintile 1) to the highest (quintile 5) intake of dietary fats. The primary outcomes of interest were estimated 24-year adjusted absolute risk differences (ARDs) for the association between dietary fat intake and mortality.
The findings
After multivariable adjustment (including adjustment for relevant food sources), when researchers compared the highest quintile to the lowest quintile, they observed that a diet with a higher intake of plant fat (HRs 0.91 and 0.86; adjusted ARDs, −1.10% and −0.73%; P for trend < .001), particularly fat from grains (HRs, 0.92 and 0.86; adjusted ARDs, −0.98% and −0.71%; P < .001) and vegetable oils (HRs, 0.88 and 0.85; adjusted ARDs, −1.40% and −0.71%; P < .001), was associated with a lower risk for overall and CVD mortality, respectively.
In contrast, after comparing the highest quintile to the lowest quintile, investigators reported that higher consumption of total animal fat (HRs, 1.16 and 1.14; adjusted ARDs, 0.78% and 0.32%; P < .001), dairy fat (HRs, 1.09 and 1.07; adjusted ARDs, 0.86% and 0.24%; P < .001), or egg fat (HRs, 1.13 and 1.16; adjusted ARDs, 1.40% and 0.82%; P < .001) was associated with an increased risk for mortality for overall and CVD mortality, respectively.
In addition, results showed that replacing 5% of energy from animal fats with an equivalent amount of plant fats was associated with a 4% to 24% lower risk for overall mortality and a 5% to 30% lower risk for CVD mortality (P < .001), highlighting the potential benefits of replacing unhealthy dietary fats.
Authors' comment
"These findings provide detailed information about how increased intake of dietary fat from plant sources may help improve human health and related mortality outcomes."