Macro partitioning
A higher proportion of saturated fatty acids relative to total fat intake (SFA/TFAT) is associated with a 23% increased risk of all-cause mortality, whereas a higher proportion of polyunsaturated fatty acids relative to total fat (PUFA/TFAT) is associated with a 14% reduced risk, mediated partially by the neutrophil percentage-to-albumin ratio (NPAR).
To support longevity, focus on the ratio of fats in your diet rather than just cutting total fat. Ensure that polyunsaturated fats (found in fish, nuts, seeds, vegetable oils) make up a larger proportion of your total fat intake, while saturated fats (found in red meat, butter, cheese) make up a smaller proportion. This shift is associated with lower mortality risk, potentially by reducing systemic inflammation.
In multivariable-adjusted Cox models, the highest tertile of SFA/TFAT ratio was significantly associated with elevated mortality risk (HR = 1.23, p for trend < 0.01). Conversely, the highest PUFA/TFAT tertile demonstrated a protective association (HR = 0.86, p for trend < 0.01)... Mediation analysis revealed that NPAR mediated 9.8% and 11.8% of SFA/TFAT and PUFA/TFAT effects on mortality risk, suggesting partial mediation through a shared inflammatory pathway.
Why this rating
Large prospective cohort (n=21,823), rigorous adjustment for confounders, but observational design limits causal inference.
Source
Association between saturated and polyunsaturated fatty acid proportions in total fat intake and mortality risk: mediation by the neutrophil percentage-to-albumin ratio
Yanyan Liu et al. · Lipids in Health and Disease · 2025
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →