Plain language summary
Flaxseed appears to be a valuable source of polyunsaturated fatty acids, phytosterols and fibre, which lower lipids and have anti-atherogenic activity. The aim of this study was to determine the effects of 10 weeks of supplementation with the flaxseed (28g/day) on endothelial cells function, serum lipids and proinflammatory mediators in patients with mild and severe dyslipidaemia. This study is a prospective study of two groups of patients. The first group (n=14) was composed of lean (n=6), and obese (n=8) outpatients receiving therapy of lipoprotein apheresis (once every two weeks) for severe hyperlipidaemia. The second group was composed of 11 obese outpatients with dyslipidaemia receiving a diet at home. In both groups, flaxseed was given blindly. Results show that patients diagnosed with dyslipidaemia who took 28g daily of flaxseed showed a significant reduction in serum lipids but exhibited a slight beneficial effect on endothelial cells. However, it only shows that flaxseed might have the potential ability to improve endothelial function but, in obese patients, it does not have the potency to reverse endothelial ultrastructural changes observed in electron microscopy. Authors conclude that flaxseed supplementation produced consistent lipid-lowering effects and can modulate VEGF (endothelial cell marker) concentration depending on the severity of dyslipidaemia.
Abstract
CONTEXT Flaxseed has a characteristic fatty acids composition and unique phytonutrient profile that may have health-promoting properties. OBJECTIVE This study aimed to determine the effects of 10 weeks of supplementation with the flaxseed (28 g/day) on endothelial cells (EC) function, serum lipids and proinflammatory mediators in patients with mild and severe dyslipidaemia. MATERIALS AND METHODS Eleven lean patients with severe dyslipidaemia treated with apheresis (group 1; 10 weeks treated in four phases: (i) ordinary diet, (ii) ordinary diet + flaxseed, (iii) ordinary diet (wash out), (iv) ordinary diet + placebo) and eleven obese patients with mild dyslipidaemia-not treated with apheresis (group 2; 10 weeks treated in two phases: (i) ordinary diet, (ii) low fat diet + flaxseed). Flaxseed was given blindly. Serum was collected at the end of each phase of the study. ECs were exposed in vitro to the medium supplemented with pooled serum taken from patients from both groups to detect their morphological changes using light and electron microscopy. ECs proliferation was also measured at the end of each study phase. RESULTS Serum vascular endothelial growth factor was decreased after flaxseed supplementation but only in group 1. ECs proliferation was increased after flaxseed supplementation only in obese patients. ECs exposed to medium supplemented with obese patients' serum revealed the following cellular abnormalities: accumulation of lipid droplets, changes of rough endoplasmic reticulum and mitochondria, and flaxseed did not reverse observed changes. At the same time, flaxseed supplementation decreases total cholesterol in both tested groups, low-density lipoprotein cholesterol in group 1 and triglycerides in group 2. CONCLUSIONS Our findings support the potential role of flaxseed in treating dyslipidaemia but indicate only a slight impact on endothelial cell function.
Methodological quality
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