Associations between nut and seed intake and non-traditional lipid indices: a cross-sectional study from the isfahan cohort study 2

Emerging evidence suggests that novel lipid indices may enhance cardiovascular risk prediction beyond conventional measures; however, their associations with dietary factors such as nut and seed consumption remain understudied. This cross-sectional study investigated associations between nut and seed intake and novel lipid indices among Iranian adults. Using baseline data from 2514 participants in the Isfahan Cohort Study 2, nut and seed intake were assessed using a validated food frequency questionnaire. Novel lipid indices, including Atherogenic Index of Plasma (AIP), Castelli’s Risk Indices (CRI-I/II), Atherogenic Coefficient (AC), Atherogenic Combined Index (ACI), Remnant Lipoprotein Cholesterol (RLPC), Triglycerides to High-density lipoprotein Cholesterol ratio (TG/HDL-C), Lipoprotein Combined Index (LCI), and Non-High-density lipoprotein Cholesterol (NHC) were calculated from fasting blood samples. Multivariable adjusted linear and logistic regression models evaluated relationships across nut and seed intake quartiles. Participants in the highest quartile of nut and seed intake had significantly lower odds of elevated AIP (odds ratio (OR) = 0.58, 95% confidence interval (CI): 0.37–0.92), ACI (OR = 0.67, 95% CI: 0.50–0.91), CRI-I (OR = 0.46, 95% CI: 0.28–0.75), NHC (OR = 0.75, 95% CI: 0.54–1.03), LCI (OR = 0.72, 95% CI: 0.53–0.97), and TG/HDL-C (OR = 0.70, 95% CI: 0.51–0.95) compared to the lowest quartile after adjustment for potential confounders. The risk reductions for RLPC, AC, and CRI-II did not consistently reach statistical significance. This cross-sectional analysis indicated that higher nut and seed intake was associated with favorable lipid profiles. These findings support the potential role of nuts and seeds in cardiovascular health. However, due to the study’s observational design, causal relationships cannot be established. Further prospective studies and randomized controlled trials are needed to confirm these associations and explain the underlying mechanisms.