Background: Studies regarding monounsaturated fatty acid(MUFA) intake and mortality have reported inconsistent findings.Dietary MUFAs can come from both plant and animal sources with divergent nutrient components that potentially obscure the associations for total MUFAs.
Hypothesis: We hypothesized that MUFA from plant sources(MUFA-P) is more likely to be inversely associated with mortality than MUFA from animal sources (MUFA-A).Replacing saturated fatty acids(SFA),trans fat,or refined carbohydrates by MUFA-P would be associated with a lower risk.
Methods: We included 63,412 women from the Nurses’ Health Study(1990-2012) and 29,966 men from Health Professionals Follow-up Study(1990-2010). MUFA-Ps and MUFA-As were calculated based on validated food frequency questionnaires collected every 4-y and food composition databases that capture changes in composition over time.
Results: During 1,896,864 person-years of follow-up, 20,672 total and 4,588 cardiovascular deaths occurred.MUFA-P was inversely associated with total mortality after adjusting for potential confounders [HR:0.84(95%CI:0.79,0.89)P<0.01], whereas MUFA-A was associated with higher risk [1.21(1.07,1.37),P<0.01].Isocalorically replacing SFAs (5% of total energy), refined carbohydrates (5% energy),or trans fat (2% energy) with MUFA-Ps was associated with 15%, 14%, and 10% lower risk of total mortality, respectively. Mortality risk was 24% lower when MUFA-Ps were modelled to replace MUFA-As(5% energy),and 20% lower when the sum of SFAs and MUFA-As(5% energy) was replaced.Similar results were observed for cardiovascular mortality for the same substitutions:HR(95%CI) were 0.74 (0.64, 0.85; P<0.01) for replacing MUFA-A and 0.83 (0.76, 0.92;P<0.01) for replacing SFA+MUFA-A.
Conclusions: Higher MUFA-P intake was associated with lower total mortality and MUFA-A was associated with higher mortality.Significantly lower mortality was observed when SFAs, trans fats,or refined carbohydrates were replaced by MUFA-P, but not MUFA-A.