Abstract
IMPORTANCE The impact of dietary fat intake on long-term human health has attracted substantial research interest, and the health effects of diverse dietary fats depend on available food sources. Yet there is a paucity of data elucidating the links between dietary fats from specific food sources and health. OBJECTIVE To study associations of dietary plant and animal fat intake with overall mortality and cardiovascular disease (CVD) mortality. DESIGN, SETTING, AND PARTICIPANTS This large prospective cohort study took place in the US from 1995 to 2019. The analysis of men and women was conducted in the National Institutes of Health-AARP Diet and Health Study. Data were analyzed from February 2021 to May 2024. EXPOSURES Specific food sources of dietary fats and other dietary information were collected at baseline, using a validated food frequency questionnaire. MAIN OUTCOMES AND MEASURES Hazard ratios (HRs) and 24-year adjusted absolute risk differences (ARDs) were estimated using multivariable-adjusted Cox proportional hazards regression. RESULTS The analysis included 407 531 men and women (231 881 [56.9%] male; the mean [SD] age of the cohort was 61.2 [5.4] years). During 8 107 711 person-years of follow-up, 185 111 deaths were ascertained, including 58 526 CVD deaths. After multivariable adjustment (including adjustment for the relevant food sources), a greater 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 for trend < .001) and vegetable oils (HRs, 0.88 and 0.85; adjusted ARDs, -1.40% and -0.71%; P for trend < .001), was associated with a lower risk for overall and CVD mortality, respectively, comparing the highest to the lowest quintile. In contrast, a higher intake of total animal fat (HRs, 1.16 and 1.14; adjusted ARDs, 0.78% and 0.32%; P for trend < .001), dairy fat (HRs, 1.09 and 1.07; adjusted ARDS, 0.86% and 0.24%; P for trend < .001), or egg fat (HRs, 1.13 and 1.16; adjusted ARDs, 1.40% and 0.82%; P for trend < .001) was associated with an increased risk for mortality for overall and CVD mortality, respectively, comparing the highest to the lowest quintile. Replacement of 5% energy from animal fat with 5% energy from plant fat, particularly fat from grains or vegetable oils, was associated with a lower risk for mortality: 4% to 24% reduction in overall mortality, and 5% to 30% reduction in CVD mortality. CONCLUSIONS AND RELEVANCE The findings from this prospective cohort study demonstrated consistent but small inverse associations between a higher intake of plant fat, particularly fat from grains and vegetable oils, and a lower risk for both overall and CVD mortality. A diet with a high intake of animal-based fat, including fat from dairy foods and eggs, was also shown to be associated with an elevated risk for both overall and CVD mortality.
Generated Summary
This study, published in JAMA Internal Medicine, investigates the associations between dietary fat intake from plant and animal sources and the risks of overall mortality and cardiovascular disease (CVD) mortality. The research is based on a large prospective cohort study that followed over 400,000 men and women in the US for up to 24 years, from 1995 to 2019, utilizing data from the National Institutes of Health-AARP Diet and Health Study. The study’s primary goal was to analyze the links between specific food sources of dietary fats and their impact on health outcomes. The researchers collected dietary information at baseline, using a validated food frequency questionnaire. They used multivariable-adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and adjusted absolute risk differences (ARDs) for the associations between different types of dietary fats and the outcomes of overall mortality and CVD mortality. The findings emphasize the importance of dietary fat sources, particularly highlighting how plant-based fats relate to health and mortality compared to animal-based fats.
Key Findings & Statistics
- The analysis included 407,531 men and women.
- During 8,107,711 person-years of follow-up, 185,111 deaths were recorded, including 58,526 CVD deaths.
- Greater intake of plant fat was associated with lower risk for overall and CVD mortality.
- HRs for overall mortality: Plant fat, 0.91 and 0.86; adjusted ARDs, -1.10% and -0.73%.
- HRs for CVD mortality: Plant fat, 0.91 and 0.86; adjusted ARDs, -1.10% and -0.73%.
- Higher intake of total animal fat was associated with increased risk for overall and CVD mortality.
- HRs for overall mortality: Animal fat, 1.16 and 1.14; adjusted ARDs, 0.78% and 0.32%.
- HRs for CVD mortality: Animal fat, 1.16 and 1.14; adjusted ARDs, 0.78% and 0.32%.
- Replacement of 5% energy from animal fat with 5% energy from plant fat was associated with a lower risk for mortality: 4% to 24% reduction in overall mortality, and 5% to 30% reduction in CVD mortality.
- Plant fat from grains: HRs for overall mortality, 0.92 and 0.86; adjusted ARDs, -0.98% and -0.71%.
- Plant fat from grains: HRs for CVD mortality, 0.92 and 0.86; adjusted ARDs, -0.98% and -0.71%.
- Plant fat from vegetable oils: HRs for overall mortality, 0.88 and 0.85; adjusted ARDs, -1.40% and -0.71%.
- Plant fat from vegetable oils: HRs for CVD mortality, 0.88 and 0.85; adjusted ARDs, -1.40% and -0.71%.
- Dairy fat: HRs for overall mortality, 1.09 and 1.07; adjusted ARDs, 0.86% and 0.24%.
- Dairy fat: HRs for CVD mortality, 1.09 and 1.07; adjusted ARDs, 0.86% and 0.24%.
- Egg fat: HRs for overall mortality, 1.13 and 1.16; adjusted ARDs, 1.40% and 0.82%.
- Egg fat: HRs for CVD mortality, 1.13 and 1.16; adjusted ARDs, 1.40% and 0.82%.
- During up to 24 years of observation and 8,107,711 person-years, 185,111 deaths were recorded, including 58,526 from CVD.
- In models 1 and 2, higher plant fat intake was associated with a reduced risk for overall and CVD mortality.
- After additional adjustment for relevant food sources (model 3), the inverse associations of plant fat intake remained statistically significant, with the HRs for overall mortality being 0.95 (95% CI, 0.94-0.97), 0.93 (95% CI, 0.91-0.95), 0.91 (95% CI, 0.90-0.93), and 0.91 (95% CI, 0.89-0.93) for quintiles 2 through 5, compared with quintile 1 (P for trend < .001; Table 2; eTable 3 in Supplement 1).
- Corresponding adjusted ARDs of overall mortality comparing the highest vs the lowest quintile was -1.10% (95% CI, -1.60% to -0.64%; Table 2).
- The HRs of CVD mortality were 0.93 (95% CI, 0.90-0.96), 0.90 (95% CI, 0.87-0.93), 0.87 (95% CI, 0.84-0.90), and 0.86 (95% CI, 0.82-0.89) for quintiles 2 through 5, compared with quintile 1 (P for trend < .001; Table 2; eTable 3 in Supplement 1).
- Corresponding adjusted ARDs of CVD mortality comparing the highest vs the lowest quintile of intake was -0.73% (95% CI, -1.10% to -0.40%; Table 2; eTable 3 in Supplement 1).
- In model 3, a higher intake of plant fat from grains or vegetable oils was associated with a reduced risk for overall mortality (quintile 5 vs 1: HR, 0.92 and adjusted ARD, -0.98% for fat from grains; HR, 0.88 and ARD, -1.40% for vegetable oils) and CVD mortality (HR, 0.86 and adjusted ARD, -0.71% for fat from grains; and HR, 0.85 and adjusted ARD, -0.71% for vegetable oils) (all P for trend < .001; Table 3; eTables 5 and 6 in Supplement 1).
Other Important Findings
- The findings suggest a consistent, albeit small, inverse relationship between plant fat intake, particularly from grains and vegetable oils, and a reduced risk of both overall and CVD mortality.
- A diet with a high intake of animal-based fats, including those from dairy and eggs, was shown to be associated with an increased risk of both overall and CVD mortality.
- The inverse association of plant fat intake with overall mortality was significant among younger participants (</=60 years at baseline) and those who consumed 1 to 3 alcoholic drinks per day.
- The positive animal fat-mortality association was greater for men, those aged 60 to 65 years, or with lower BMI (</=25), or consuming 1 to 3 alcoholic drinks per day, and during the first 5 years of follow-up, for which all interactions were statistically significant.
- The association of animal fat intake with CVD mortality was stronger among younger participants and during the 5 to 10 years of follow-up.
- Replacing 5% energy from total animal fat, red meat fat, dairy fat, or egg fat with an equivalent amount of total plant fat, fat from grains, or vegetable oils was associated with a 4% to 24% lower risk for overall mortality and a 5% to 30% lower risk for CVD mortality (P < .001).
- In model 3, a higher intake of plant fat from grains or vegetable oils was associated with a reduced risk for overall mortality (quintile 5 vs 1: HR, 0.92 and adjusted ARD, -0.98% for fat from grains; HR, 0.88 and ARD, -1.40% for vegetable oils) and CVD mortality (HR, 0.86 and adjusted ARD, -0.71% for fat from grains; and HR, 0.85 and adjusted ARD, -0.71% for vegetable oils) (all P for trend < .001; Table 3; eTables 5 and 6 in Supplement 1).
- In model 3, higher intakes of fat from dairy products and eggs were associated with increased risks of overall mortality (quintile 5 vs 1: HR, 1.09 and adjusted ARD, 0.86% for dairy fat; and HR, 1.13 and adjusted ARD, 1.40% for egg fat, respectively; P for trend < .001; Table 3; eTable 5 in Supplement 1), CVD mortality (quintile 5 vs 1: HR, 1.07 and adjusted ARD, 0.24% for dairy fat; HR, 1.16 and adjusted ARD, 0.82% for egg fat, respectively; P for trend < .001; Table 3; eTable 6 in Supplement 1), and heart disease mortality (quintile 5 vs 1: HRs, 1.09 and 1.14 for dairy and egg fat, respectively; P for trend < .001; eTable 7 in Supplement 1).
- Greater intake of fat from white meat was associated with a lower risk for overall mortality (quintile 5 vs 1: HR, 0.95 and adjusted ARD, −0.75%; P for trend < .001; Table 3; eTable 5 in Supplement 1), but not CVD (HR, 0.97 and adjusted ARD −0.04%; P for trend = .47; Table 3; eTable 6 in Supplement 1), heart disease (HR, 0.96; P for trend = .26; eTable 7 in Supplement 1), or stroke mortality (HR, 1.06; P for trend = .21; eTable 8 in Supplement 1).
- In model 2, a higher intake of red meat fat was associated with an increased risk for overall mortality, CVD mortality, and heart disease mortality (quintile 5 vs 1: HRs, 1.11 [95% CI, 1.09-1.14], 1.09 [95% CI, 1.05-1.14] and 1.11 [95% CI, 1.06-1.17], respectively; all P for trend < .001; eTables 5-7 in Supplement 1).
Limitations Noted in the Document
- The study’s observational design might not account for all potential confounding factors.
- Dietary data collection relied on food frequency questionnaires, which could be subject to measurement errors, potentially leading to biased estimates.
- Dietary intake was calculated based on baseline data, and may not reflect dietary modifications during the follow-up period.
- The study population was primarily non-Hispanic White, which limits the generalizability of the findings to other racial and ethnic groups.
Conclusion
The findings from this extensive cohort study indicate a significant association between dietary fat sources and mortality risks. The data strongly support the idea that increased consumption of plant fat, especially from grains and vegetable oils, is linked to a reduced risk of both overall mortality and CVD mortality. This is in contrast to the observed risks associated with animal-based fats, including those from dairy and eggs, which were associated with increased mortality risks. The study’s outcomes align with the broader context of nutritional science, underscoring the advantages of plant-based diets for human health. The study highlights that substituting animal fats with plant-based fats could lower the risk of mortality. As noted in the findings: “greater intake of plant fat, particularly fat from grains or vegetable oils, was associated with a decreased risk for overall mortality and CVD mortality.” The association between animal fat intake and increased risks also aligns with other research. The key takeaway from this research is that the source of dietary fat matters, and a shift toward plant-based fats could substantially benefit public health. The study’s findings offer detailed, relevant insights for dietary guidelines and underscore the need for policies that promote plant-based eating for better health outcomes, as the study details that “Replacement of animal fat with an equivalent amount of plant fat, particularly fat from grains or vegetable oils, was associated with a lower risk of mortality.”