Linking Flaxseed Intake to Lipid and Metabolic Health: Associations with Metabolic Dysfunction Indices and LDL-Subfractions in Slovak Menopausal Women

Background/Objectives: The aim of the present study was to investigate the effects of flaxseed consumption on selected metabolic health indicators in menopausal women following an eight-week dietary intervention. Methods: The study cohort comprised 34 menopausal women aged 45–55 years who were voluntarily recruited from the general population. The intervention lasted for eight weeks, during which participants received 40 g of ground flaxseed daily. Biochemical blood parameters were measured using a BioLis 24i Premium automatic analyser. Body composition was assessed using an InBody 720 device. Lipoprotein subfraction analysis was performed using the LipoPrint® LDL System. Metabolic indices were calculated according to established equations. Results: Overall, the present findings suggest that the most pronounced changes following flaxseed supplementation occurred in selected lipid parameters, particularly LDL-C, total cholesterol, VLDL, IDL-A, and IDL-B. In contrast, HDL-C, TG, glucose, liver enzymes after multiple-testing correction, anthropometric measurements, and the investigated surrogate indices of adiposity and metabolic dysfunction did not show statistically significant changes. The calculated metabolic indices (C-I, BRI, HSI, LAP, TyG-I, TyG-BMI, TyG-WC, TyG-WHtR) suggest preferential visceral fat deposition and an alteration in adipose tissue distribution. Conclusions: Flaxseed supplementation produced a heterogeneous lipid response, with decreased LDL-C but increased total cholesterol, VLDL, and IDL. No significant changes were observed in other lipid, glycemic, anthropometric, or calculated metabolic parameters after correction for multiple comparisons. These findings do not support a uniformly favorable cardiometabolic effect and warrant further investigation.