RESUMEN
BACKGROUND: Linseed oil has cardio-protective effects. However, its antihypertensive action has not yet been well characterised. AIM: The primary purpose of the study was to evaluate the effect of short-term dietary supplementation with linseed oil on blood pressure (BP) and lipid metabolism in patients with mild hypercholesterolaemia. The secondary aim was to assess the effect of linseed oil on nitric oxide pathway and selected serum trace metals. METHODS: 150 volunteers: 43 men (49.9 ± 11.5 years) and 107 women (53.2 ± 10.3 years), diagnosed with mild hyper-cholesterolaemia, were assessed prospectively for BP and lipid levels, before and after lipid-lowering diet plus linseed oil supplementation at a dose of 15 mL daily for four weeks (study groups) or four-weekly lipid-lowering diet (control group). Multivariate logistic regression analysis was used to determine the effect of linseed oil on BP after adjustment for age, sex, height, body weight, body mass index, smoking status, and alcohol consumption. RESULTS: Supplementation with linseed oil significantly decreased low-density lipoprotein (LDL)- and non-high-density lipo-protein (HDL) cholesterol, and increased HDL- and HDL3- cholesterol levels. Additionally, linseed oil decreased diastolic BP in men (95% confidence interval [CI]: -6.0 to -1.1, p < 0.006), whereas in women linseed oil reduced (p < 0.001) systolic BP (-3.6 mmHg; 95% CI: -5.8 to -1.5) as well as diastolic BP (-4 mmHg; 95% CI: -5.8 to -2.1). Women with higher BP displayed an increase in serum L-arginine level (p < 0.01). In the logistic regression model oil consumption was associated with a decrease in mean BP (adjusted odds ratio 3.85; 95% CI 1.32-11.33). CONCLUSIONS: Our findings confirm the benefit of short-term linseed oil use in mild hypercholesterolaemia, particularly in patients with increased blood pressure.